Important: If your clutch is dragging, stop driving the car immediately. Read Jack's transmissions Clutch Drag Kills Syncros.
Poor shifting is a hallmark of 1G cars. 2G owners have vastly improved transmissions, and do not generally suffer from bad shifting. If you have a 2G that has shifting problems, you must read about possible problems with crankwalk on the 2Gs.
For 1G cars, there are several fixes. There are also several TSBs on this problem, for various years. Check the NHTSA site for TSB information. Remember, TSBs are neither warranties nor recalls.
Solution #1 came up in 1992 when the first TSB called for adding a 'friction modifier' to the transmission fluid. The modifier increases the frictional coefficient of the fluid, so the synchronizer rings (synchros) match speeds faster. There have also been several synchro design updates throughout the various years, intended to improve the crunchy shifting. Of course, to take advantage of these requires a transmission rebuild.
Many DSMers recomment using Redline MT90 or Genuine Mitsubishi DIA Queen in place of the Redline MTL from years ago. Not many are left using BG Synchroshift or GM Synchromesh days due to claims of early syncro failure among the majority. All of these fluids have the same purpose - to increase friction, just as the Mitsu fluid modifier is intended to do. Most owners report at least some improvement with the new fluids, but most experience significantly better shifting. Opinions and experiences vary.
Recent experience suggests that Redline MTL gains in shifting performance by sacrificing synchro longevity. This is not exactly news, but more and more owners are reporting this problem with MTL now that there are alternative fluids available. Many owners considered the tradeoff to be well worth it. However, more people are now recommending a mix of Redline MTL with MT-90 gear oil, to combat both problems at once or just use straight MT-90.
Poor clutch disengagement has recently become a suspect for poor shifting in DSM cars. Refer to [[What are the symptoms of poor clutch disengagement?]] for more information. There is a great writeup on hotrod.com | How to Diagnose Your Own Clutch System Problems - Be Your Own Disc Doctor (or download archive PDF)
Problems have sometimes been found in the shift linkage as well, leading to the Tighter Shifter Page (90-94) (or download archive PDF) that describes how to rebuild the linkage in 1G DSMs for improved performance. Kyle Jones even found that an incorrect aftermarket lower radiator hose was interfering with his shift cables and causing crummy shifting; cutting the hose shorter did the trick.
The Last Word: Eric B. would like to add:
"On the topic of Redline gear oil eating away the syncronizers in your transmission, there is a reason for that. It is the wrong API service grade (GL-5). Chemically, GL-5 isn't friendly with brass and will deteriorate your syncros, which is why differentials and transfer cases seemingly only call for it. Almost all (if not all?) transaxles require a GL-4 service oil. This is most overlooked by everyone. I found out the hard way also from my other car's transmission. I verified this being the cause of failure from a handful of machinist and transmission specialists. By mixing it as stated on the page, it is merely being dilluted and the corrosive effect is still existing, but reduced."
Sean Costall: "Personally, my car has had MTL and Syncroshift in it since '96, and it still shifts fine on the original tranny. YMMV. [Thanks, Eric!]"
For those owning a new clutch, it is normal for the engagement point to drop low. The DSM clutch mechanisms are so constructed as to move the engagement point higher as the clutch wears.
Next try Jafromobile - Bleed your clutch.
Gary Selph, John Snodgrass and Kevin Fabec all found one of the connecting rods for the clutch mechanism was worn, causing the clutch to engage lower that it should. This may be a fairly common but easily overlooked problem, especially on older cars. A good test is to see if you can pull the clutch pedal up with your foot. If you can, the rod is likely worn.
Another commonly overlooked clutch problem is wear on the clutch fork or pivot ball. The clutch fork could also possibly be bent, especially if heavy-duty clutches have been used. The pivot ball and clutch fork have both been mentioned as 'wear items' and should be considered for replacement if a new clutch is going in anyway.
Of course, the problem may also be related to the clutch master cylinder. Replacing the cylinder and clutch lines can sometimes fix the problem. A few people have used stainless steel lines. It is far from required, but some people have found a steel line improved the clutch pedal feel quite a bit.
Poor clutch pedal feel can often be attributed to binding of moving mechanical parts. Alternatively, problems in the clutch hydraulic system may be to blame, or a combination of both.
Despite popular opinion, it is possible to have a DSM that has a 'good' feeling clutch pedal. The key points appear to be to grease all the moving parts - throwout bearing, clutch fork and pivot ball - with a high-quality grease, and to replace the old stock clutch line with a stainless steel line (or, at least, a new rubber line). These items combine to prevent mechanical friction and hydraulic problems that can contribute to a poor clutch pedal feel.
Stronger clutches such as Centerforce Dual-Friction and ACT 2600 clutches have long had the reputation of providing a very stiff pedal. In these cases is it even more important that the clutch installation pay particular attention to the above items. In some cases, owners have reported their 'heavier' clutches feel better than 'lighter' clutches in a different car.
If you have the money, you can look at Twin Disc Clutch System from ACT ($1400+)
Poor clutch disengagement can lead to the following problems:
In summary, here are most of the possible causes of clutch engagement/disengagement problems and their solutions. They are ranked in rough order of least difficult/expensive to most difficult/expensive. Most of these symptoms also apply to shifting problems that can manifest due to poor clutch disengagement.
|Air or water in clutch hydraulic fluid||Bleed clutch fluid and replace.|
|Master cylinder is leaking.||Replace master cylinder.|
|Slave cylinder is leaking.||Replace slave cylinder.|
|Clutch pedal rod is worn out.||Replace rod.|
|Master cylinder pushrod is incorrectly adjusted.||Readjust master cylinder rod.|
|Incorrect clutch pedal free play adjustment.||Readjust clutch pedal free play.|
|Transmission is loose, resulting in movement when clutch is depressed.||Tighten loose transmission bolt(s) by front engine mount.|
|Master cylinder rod too short for current clutch setup.||Lengthen master cylinder rod.|
|Master cylinder worn out.||Replace old master cylinder.|
|Slave cylinder worn out.||Replace old slave cylinder.|
|Poor lubrication on clutch fork and/or pivot ball.||Grease moving parts well.|
|Worn clutch fork pivot ball.||Shim pivot with one or two 3/8" washers to regain missing travel.|
|Poor lubrication on pilot shaft or throwout bearing.||Grease throwout bearing very well.|
|Worn or bent clutch release fork.||Replace fork.|
|Worn clutch pivot ball.||Replace ball.|
|Worn out or incorrectly installed clutch / flywheel.||Replace clutch / flywheel with new clutch and flywheel machined to correct specifications.|
Paying attention to the above items can make your next clutch swap a real success.
This is a symptom of a serious problem, at least on 1G DSMs. Shifter movement is not generally normal in DSMs. Having the shifter move around, especially in 5th gear, or popping out of gear (even once or twice) could be an indication of a loose retaining nut inside the transmission. Several 1G DSMers have had the rotten experience of having this nut come off completely, and consequently blasting a hole in their transmission. This problem only affects FIFTH gear - gears 1 through 4 and reverse do not appear to suffer from this difficulty.
Those who are uncertain must know that both by Paul Lyons and Ashok Babu had their transmissions fail on them. Don't take a chance on this one, since the inspection procedure is easy.
This problem does not appear as common on 2Gs, and at least one owner has reported that there was a loose nut in his shifting assembly that was causing the shifter to pop out of 5th. This is NOT the same nut that is involved in the 1G problem.
David Cox had a problem where the engine RPMs would jump and the car wouldn't accelerate. In his case, it was the torque converter. Dan Henderson also had this problem, but all that was required was to refill the transmission with the correct amount of fluid.
In the case where the automatic transmission works except for the overdrive (4th gear), Kurtis Bredda had the "end clutch" (Mitsubishi part # MD723508) fail. Please see http://www.plymouthlaser.com/ for information on end clutch replacement.
According to Terry Livermore in the July 8, 2000 Digest:
"Winding down or "coast down" whine or howl noises that go away when the accelerator is depressed are often caused by a loose or worn drive pinion bearing in the rear differential. These are usually loudest between 45 to 25 MPH. I once pulled the transfer case and driveshaft and drove a little to make sure before I decided where mine was coming from."
Transmission shaft spline wear can incorrectly be blamed on 'rusting'. It is usually the result of loose parts in the driveline setup that shift around, eventually grinding away the splines.
Read Jack's Transmissions page about output shaft spline wear
The shift knob is just screwed onto the shifter. Grab it tight and turn it counterclockwise. Use lots of force, it will begin to unscrew. Just screw the new one on, or mount it in place with lock bolts if that is required.
Many 1990-1992 owners find the 1993-1994 shift knob a nice replacement.
Thread pitch on 1G/2G shifter is M10 x 1.25mm
This thread pitch is shared with some mazdas Ex: Mazda 3 Miata MX3 MX5 MX6 Eunos Protégé 5 323 626 Mazdaspeed JDM
This is by far the best video series. Made by Jafromobile for a Clutch & Tranny in AWD 2G.
A clutch swap is not a simplistic procedure and should only be attempted after due experience, or when you have lots of time to learn.
Note that there are two possible replacement throwout bearings for DSMs. One is all-metal, one is lined with plastic. Many DSMers recommend using the plastic lined one. This is because the throwout bearing rides on an aluminum shaft, and the metal bearing can score this shaft over time.
Along with the clutch, the following items should be considered for replacement. Note that not all parts need be replaced each clutch swap; most can be retained unless you are having problems with poor clutch disengagement or poor pedal feel.
The master and slave cylinders will generally show signs of leaking if they require replacement. The pedal line will probably not, but won't help much beyond possibly improving the pedal feel. The release fork and pivot ball may not show any significant signs of wear, but might be worn nevertheless. The flywheel need only be replaced if you desire a lighter version, or if the present flywheel is damaged beyond the capacity of resurfacing to repair.
Lots of people. Opinions vary on driveability, but most racers seem to like them.
A popular option is the XACT Streetlite Flywheel.
Many people have, although few recommend doing so for street-driven cars. There are actually two different versions of this modification - one for FWD cars and one for AWD cars.
FWD vehicles often suffer from excessive wheelspin on one drive wheel. While the one wheel is spinning, the other wheel loses power and cannot drive the vehicle forward. Winter drivers may recognize this situation from experience, as many drivers have become stuck in icy conditions when one drive wheel starts to spin. Although the other wheel might be on solid ground, it cannot get power, and the vehicle goes nowhere.
In this case, welding the front axle differential forces both front tires to rotate at the same speed, so the lost power is recovered. It is no longer possible for one wheel to spin without the other also spinning.
Of course, you don't get something for nothing - the differential is there for a reason. The main reason is that, when cornering, the wheels at the inside of the corner must travel a shorter distance than the wheels on the outside. The differential allows the wheels to rotate at different speeds. Eliminate the differential, and cornering becomes a lot more difficult, causing unusual suspension and drivetrain stresses.
AWD vehicles have a different problem. Many AWD car owners would like to measure their engine output on a chassis dyno - a big set of stationary rollers that can measure the force imparted to the wheels. The problem is that there are almost no dynos capable of handling a four-wheel-drive vehicle.
The simple solution to this problem is to remove the AWD transfer case, which distributes power between the front and rear driveshafts, and temporarily convert the car to a FWD vehicle. Alas, it is not that simple. Most AWD DSMs have a limited-slip differential installed between the front and rear axles. This component is designed to allow the front and rear driveshafts to rotate at different speeds - up to a point. If the front and rear axles start to rotate at radically different speeds, the hydraulic mechanism in the differential 'lock' the driveshafts together and force the front and rear axles to rotate in sync.
So? Well, removing the transfer case creates a situation where the front and rear axles are out of sync, all the time. The limited-slip differential 'sees' no rotation from the front driveshaft (which is now disconnected), yet there is rotation of the rear driveshaft (which is being rotated as the car moves). The limited-slip mechanism promptly locks, and stays locked. The differential was never designed to operate in this permanently locked state, and serious damage will quickly result.
To get around this problem, the limited-slip differential in the AWD DSM can be welded to ensure it is mechanically, and not hydraulically, locked. This eliminates problems with removing the transfer case, and allows an AWD DSM to be converted to FWD operation for dyno runs. Converting back is as easy as replacing the transfer case, although this isn't really that easy.
Unfortunately, it also means that the front and rear axles must always operate perfectly in sync, which is not usually the case while cornering. One or more tires in this setup with inevitably slip, as they are pushed off their direction of travel; odd handling and strange driving behavior might result. The situation is similar to the operation of manually-locked 4WD vehicles (trucks & off-road vehicles) while making tight turns - wheels will drag, and the drivetrain will 'hitch' or 'catch' as the 4WD mechanisms try to keep all four wheels rotating at the same speed while they travel different distances.
The handling problems with welded differentials usually restrict them to drag racing applications only.
Micheal Hamilton has done this on an unspecified 1G FWD. It is complex procedure requiring an estimated at 9 hours, install only, plus additional time or cost for removing/acquiring the required transplant parts.
In addition to Micheal's work, you may read the [[What are the differences between a automatic tranny car and a manual tranny car?]] for an idea of what you may need in addition to the transmission components.
Here is a thread about what you need on DSMTunners - AWD Automatic To Manual Swap
Important: DSMs are cheap. Just buy what you want.
Most people who research this topic come to the conclusion that it is cheaper to sell the FWD and purchase an AWD DSM, rather than attempt to convert the FWD to AWD form. Road Race Engineering has done this; the cost is $6000.
With AWD DSMs running in the $1500 - $8,000 area, why would you want to do this? Do yourself a favor and just buy an existing AWD.
Important: DSMs are cheap. Just buy what you want.
Yes. Dave Buschur had what was perhaps the first-ever RWD DSM back in 1998. To do it, he rotated the engine ninety degrees in the engine bay and adapted it to a Powerglide racing transmission. For more details see Dave Buschur's biography.
While it is possible to do this type of conversion, the difficulty level is (to put it mildly) very high.
DSM transmissions come in two types with different output shafts. 1990 and some 1991 cars have 22-spline output shafts. Later 1991 through 1994 cars have 23-spline output shafts. Please note that 1991 cars that are 'later' (i.e. have later production or serial numbers) may still have the 22-spline shaft. The best way to check is to look, or to check part numbers with a dealership.
The number of splines on the transmission output shaft must match the number of splines on the transfer case input shaft, or else the transmission will not fit. Some people have found it possible to swap shafts between the transmissions in question to match the parts up correctly. Alternatively, the transfer case can also be changed to match up with the transmission, with an associated greater cost.
There have been several syncro changes over the years to try and combat problems with 1G cars not shifting well. It is generally accepted that later transmissions have superior syncro designs, so if all other things are equal a later version may be superior to an earlier version. Also, 2G transmissions can be put onto 1Gs with some simple modifications, and can provide superior performance. However, most people do not have free choice of transmissions due to economic reasons.
It must also be noted that the manual transmissions from turbo FWD and non-turbo FWD cars are different. Non-turbo FWD 1Gs have a F5M22 transmission (manual) or F4A22 transmission (automatic). Non-turbo 2Gs have a F5MC1 transmission (manual) or F4AC1 transmission (automatic). Turbo FWD 1Gs and 2Gs have a F5M33 transmission (manual) or F4A33 transmission (automatic). These transmissions are not interchangeable, and they are geared differently.
This is a relatively easy swap since the engines in the cars are the same. The manual turbo is almost a bolt-on replacement for the automatic transmission TD04.
According to Kevin Watson, the oil and coolant lines are larger on the manual TD05 turbo. Also, the exhaust manifold is different and needs to be changed to a manual transmission manifold.
Yes, Greg Clayton successfully did so, as did Jeff Hanko (95 to 91 AWD) and Brad Degrazia (96 to 92 AWD).
More and more DSMers seem to be seriously considering this swap as worthwhile.
This information was added by Randy Gonzalez in August of 2000:
"ONE: If you have a 1990 or even a 1991 with a 22 spline transfer case, then you will need to swap the xfer case as well. This is just so that the xfer case will be able to mate with the 23 spline output shaft of the 2g tranny.
TWO: When you drill holes in the dust shield to mount the starter, this CAN be done with the flywheel/clutch disk/pressure plate intact. On the VERY TOP starter hole in the dust-shield (hole that is higher above the ground), drill downwards towards the other bolt. On the hole in the dust-shield that is lower to the ground, drill upwards towards the higher hole. It is very simple, this can be done with even a file if you wanted to.
THREE: the shifter cables mount to the tranny via shift cable giudes. The information given is kinda foggy. In short, just make the guides look identical to your 1g tranny. Do this by whatever means necessary. I just grabbed a pair of pliers and bent the guides until they looked decent enough to install. It didnt' look all great or anything, BUT it shifts great now. I think that is all that really needs to be mentioned to better the information already given to the archives... And to let DSMers know, the 2g tranny is such a BIG upgrade over my 91 tranny. It used to be SO damn notchy all the time no matter how well you pampered it into gear. Now with the 2g tranny, all the shifts are as smooth as a knife through butter. I haven't track tested it yet but I am sure it will hold to my expectations. I didn't cut off the ballast weight. Mainly because I figured that if Mitsu put it there, then it had to serve some sort of function other than to slow down shifts. If that IS the only reason, then my loss. but I just rather be on the safe side on this one; plus, I never hear about 2g DSMers cutting it off their tranny. So why should I? Hope this helps someone in the future of those that are pondering whether to do the install or not."
The engine control unit (ECU) only does the engine - there is a separate transmission control unit (TCU) that operates the automatic transmission. The ECU and TCU do not talk to each other. The TCU gets information regarding throttle position, RPM, etc. by sharing the same sensors used by the ECU.
Enjoy these retro videos!
If you want something a little less dry and covers only the rebuilding of the driveshaft, Jafromobile strikes again with a 5 part series.
This varies wildly. Ask on the forums for assitance in choosing the right clutch for your setup.
A beefed up version of the stock clutch with more clamping force and a sprung full-face friction disc. This clutch is recommended for a daily driver with stock or near stock power. Pedal pressure similar to stock. Torque rating 300 ft/lbs.
Stage 2 Daily:
Comes with a heavy-duty pressure plate with increased clamping force over stock. Friction disc is an organic disc with a high metal content that increases the co-efficient of friction to twice that of the stock disc. Pedal pressure similar to stock. Recommended for a daily driver that sees occasional track use. Torque rating 320 ft/lbs. (For comparison, this clutch would have similar performance to an ACT 2100 w/street disc.)
Stage 2 Endurance:
Comes with a heavy-duty pressure plate with increased clamping force over stock and with the fulcrum slightly altered for positive disengagement and quick shifts. The friction disc is of a hybrid design: full-face feramic (sintered iron) lining on the flywheel side and high metal content organic lining on the pressure plate side. Engagement is positive yet buffered due to the high graphite content unique to feramic facings. Pedal pressure similar to stock. Recommended for a daily driver that sees occasional drag use but with emphasis on rally or endurance racing. Torque rating 415 ft/lbs. (For comparison, this clutch would have performance characteristics somewhere between an ACT 2100 & 2600 with a lighter pedal.)
Stage 2 Drag:
Comes with a heavy-duty pressure plate with increased clamping force over stock and modified for a puck-style disc. The friction disc is of a 6-puck design which reduces rotational mass while increasing pressure on the surface of the friction material. Additionally, there is no cushion material between friction linings which helps keep clutch pedal travel short and quick. The friction material is graphite-impregnated ceramic. This compound exceeded all other friction materials when tested for durability, reduced chatter, heat transfer and torque capability. Pedal pressure slightly more than stock. While this clutch CAN be used on a street machine, it is designed and is generally recommended for drag racing. Torque rating 465 ft/lbs. (For comparison, this clutch would have similar performance to an ACT 2600 w/6-puck disc with a lighter pedal.)
Stage 3 Daily:
Comes with a heavy-duty pressure plate with significantly increased clamping force over stock. Friction disc is an organic disc with a high metal content that increases the co-efficient of friction to twice that of the stock disc. Pedal pressure about 25% stiffer than stock. Recommended for a daily driver that sees occasional track use. Torque rating 400 ft/lbs. (For comparison, this clutch would have similar performance to an ACT 2600 w/street disc with a lighter pedal.)
Stage 3 Endurance:
Comes with a heavy-duty pressure plate with significantly increased clamping force over stock and with the fulcrum slightly altered for positive disengagement and quick shifts. Friction disc is designed for the special needs of a vehicle with circuit racing in mind. Kevlar friction material is used for its unique static-to-dynamic co-efficient ratio at high energy levels which translates to a perfect transition from one gear to the next. Pedal pressure about 25% stiffer than stock. While this clutch CAN be used for spirited daily driving and occasional drag use, it is designed and is generally recommended for rally, endurance racing, clubsport and autocross. Torque rating 450 ft/lbs. (For comparison, this clutch would have similar performance to an ACT 2600 with a lighter pedal.)
Stage 3 Drag:
Comes with a heavy-duty pressure plate with significantly increased clamping force over stock and modified for a puck-style disc. The friction disc is of a 6-puck design which reduces rotational mass while increasing pressure on the surface of the friction material. Additionally, there is no cushion material between friction linings which helps keep clutch pedal travel short and quick. The friction material is graphite-impregnated ceramic. This compound exceeded all other friction materials when tested for durability, reduced chatter, heat transfer and torque capability. Pedal pressure about 25% stiffer than stock. While this clutch CAN be used on a street machine, it is designed and is generally recommended for drag racing. Torque rating 525 ft/lbs. (For comparison, this clutch would have similar performance to an ACT 2900 w/6-puck disc with a lighter pedal.)
Visit Jack's Transmissions DSM Clutch Selection page.
Two clutches that are gaining popularity are Southbend Clutch w/ XACT Streetlite Flywheel or an ACT Twin Clutch Setup.
Dog Box Transmissions
Dog engagement is normally used in racing applications where fast, precise shifting is needed. Dog gear engagement is facilitated by numerous large teeth (dogs) that mate into matching openings machined into the opposite surface of the drive gear. Unlike the synchro engagement, there is no synchronizing mechanism to assist in equalizing speed. Ideal gear selection—e.g. minimal clashing and wear of the dog rings—is achieved by quick shifts; the motto here is “the quicker the better”, so bang away.
Most modern cars are fitted with a synchronized engagement gearbox from the factory to deliver smooth, reliable, and quiet operation, which is paramount for a daily driven vehicle. Synchromesh transmissions operate using a collar that applies force to a cone-shaped clutch attached to the gear. The collar allows the shaft speed of the gearset and the input shaft to be matched or “synched” to the output shaft prior to the collar locking into place and initiating a shift.
Synchromesh gear engagement is best at lower engine speeds and requires a bit more time compared to a dog box, to facilitate shifts. Limitations of synchromesh gearboxes in high-performance applications include slow upshifting at very high engine speeds—e.g. 9,000 rpm—and slow downshifting, as well as the need to fully use the clutch.
Full article here: Gearbox Beatdown - Synchromesh vs. Dog Box
Get some tubing to put of the bleeder vavle on the slave cylinder. Put a little clutch fluid in a small jar and submerse the end of the tube into it.
Have your assistant pump clutch 3 times. Open valve, Close Valve when it's done pushing fluid out.
Rinse and repeat.
Every 3 times you crack the valve, check to make sure resevoir is not low on fluid or you will need to start all over again.
The fluid in the jar prevents air from being sucked back up into the system. Stop once you are confident there is no more air in the system.
Copyright DSMFAQ (Chuck Lavoie) / 1000AAQ (Sean Costall) 1989 - 2021
Site seen by 1031971 visitors