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popping out of 4th gear

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luv2rallye

DSM Wiseman
8,626
1,360
Jun 7, 2003
Minneapolis, Minnesota
4th has lately liked to pop out right after I shift into it unless I hold it in for a second, then after that its fine until the next shift into 4th. Or if I slam it into 4th from 3rd really hard then its fine until the next shift into 4th. When stopped I have to let up the clutch very slowly before it will pop into reverse also. All other gears shift fine and stay in.

I have searched and found causes of bad synchros, bent shifter fork, or worn hub & sleeve. Now I had this same identical problem 18 months ago (no problem before that since I bought it new) and had the tranny overhauled which fixed it (new forks, synchros, new 4th gear). I have been gentle on the shifts, always kept the fluid full of pennzoil synchromesh, and not put many miles on since then. How could this tranny be going bad already or could it be something else like worn motor mounts or the tranny's two 36mm nuts coming loose (link shows 1g but I assume 2g has same): http://www.geocities.com/qwik93awd/Vfaq/shifter.htm. Any ideas or comments?
 
What about shifter cable adjustment being the problem? That tranny shouldn't be causing you grief already. :confused: Shifter cable bracket bolts could be loose?

Also on a 1g when you shift into 4th, the linkage under the hood comes VERY close to the lower rad hose & water pipe. Maybe yours is hitting and wants to just spring back out of gear...
 
It really sounds like a bad syncro or bent fork, but i would definetely try torqing the 36mm nuts, and checking the wave spring. I know you said you have been babying it, but is there any chance you missed a hard shift into fourth? Also when going into reverse, bump 1st then go into reverse, and if your going into 1st, bump 2nd. This slows the syncros down and will allow the gears to mesh easier. Also if you havent already check to see if your linkage is making contact with your lower radiator hose. Let me know
 
Today I checked the linkage and it's not bumping into anything. Also the mounting bracket for the cables on the tranny is on solid. I disconnected the (2,4,R) cable from the tranny shift lever (I also have the skateboard bearing mod on here as well as the Symborski kit on the shifter so there's no play) to see if the lever is being pushed all the way forward. It is with lot's of shift cable left over. So that tells me the problem has to be in the tranny itself. :cry: No not again! :mad:

Seems the "have to let up the clutch very slowly before it will pop into reverse" should be a clue. This started happening before the 4th gear shift problem and it happened 18 months ago before the rebuild the same way also. Anyone on this?

I'll try checking those 36mm nuts next. Manual says 109 ft-lbs. How do you hold the shafts w/o damaging anything?
Also what should I check for on the wave spring? I see it in the manual but what is it for?
 
I'll try checking those 36mm nuts next. Manual says 109 ft-lbs. How do you hold the shafts w/o damaging anything?


I'm not sure what you're asking. This is what the link says:

Now you will need to go to the driver side splash shield behind the wheel and remove the round rubber grommet so you can get to the bolt that will secure the crank shaft so the engine doesn't rotate while you are torqueing down those 36 mm nuts. I used a socket and a large 1/2" drive breaker bar. Just put the socket on the bolt and have the breaker bar pointing toward the floor.

Go back to the passenger side. Now you will need that torque wrench and a 36 mm socket. If the nuts are real loose you can just torque them down. If they appear tight, loosen them first then torque them back down. Slowly start to tighten the top nut, you will notice your breaker bar on the other side of the car will start to turn until it is resting against the lower control arm on the suspension. Now you will be able to torque this nut to 108-110 ft lbs. (tight!). Do the same to the lower nut.


This method works for 2g's also. I've done it on my brothers GST and didn't have any problems.
 
ok yes that is what I was asking. I knew about holding the crank but wondered if the more direct holding of the shafts the nuts are on was possible and better (like wedging a screwdriver between the gear teeth). Also should I use lock tight on the nuts if they were loose as well as the dimples (so it maybe won't happen again)? And buy new nuts?
 
To me it sounds more like your detents. They are what holds the shift rail in place and keeps it from popping out of gear. We have 3 of them. Put the trans in neutral. There are 3 bolts that are on the passenger side of the trans facing the front of the car. Thats where the detents are. pull them and check the springs and balls. Most ppl think its bad synchros or this or that. Most of the time its as simple as a bad detent spring. If not fixed, then yes, your fork can be worn or the clutching teeth of the synchros can be worn too.
 
I cannot reply on the inner workings of the tranny.

I do know that the VFAQ for a 1g states that you can put a penny in between the teeth of those gears because it won't damage anything but will lock them in place when they try to turn as you tighten the 36mm nuts. I never tried it because mine were tight enough.
 
Honestly i think you may have a broken poppet spring or your syncronizer hub to sleeve spline clearance is out of spec. I would recommend using a rag to put between the gears to tighten the 36mm nuts. If you were to use a screwdriver id be worried about dingin up your gears. The smallest little nick in the gears will create an awful knock.Yes i would use locktight.;)
 
Wouldn't a rag just get torn to shreds and get mashed up in the gearing? The penny idea sounds interesting since it is a much softer metal than the gears and should just get flattened. What does anyone else say about the penny - would it damage the teeth?
I'm praying its just the poppet but I want to be prepared and hear other ideas also.
 
Those gears are machined with extremely close tolerances. Try the rag you will be surprised how it holds up.:thumb:
 
Those gears are machined with extremely close tolerances. Try the rag you will be surprised how it holds up. Just ball it up shove it in the gears and start torqing.

I would never in a million years put any kind of metal inbetween the gears. I've learned from my mistakes;)The copper penny sounds like it may work, but i still would never try it.
 
Problem found: I checked the poppet springs & balls and they were ok. The 36mm nuts are also extremely tight. I now have the tranny out and apart and I found the problem. The 3rd-4th shift fork width is extremely worn where it fits into the synchronizer sleeve such that it can move back and forth way too much and easily let it pop out of 4th. The part that fits into the sleeve is now at 0.315" width where it started out at 0.385". It wore down the entire radius of the fork. The synchronizer sleeve groove is 0.390" wide. I'm ordering new forks and nuts tomorrow from Satan. Perhaps the aftermarket one they put in 2 years ago was the problem (poor quality aluminum?). There was also a small piece torn out of an oil guide but I doubt it caused the problem since that is on the end of the other gear shaft (intermediate gear assembly). As far as reverse all I can find is the reverse idler gear teeth are somewhat rounded instead of pointed.

Oh and the penny/dime holding the gears link is here: Dre but we just put it into 2 gears at once (5th and one other) to hold it so the 36mm nuts can be removed/installed. To get it into 5th just remove the 5th fork's spring pin and manually push the synchronizer sleeve into 5th.
 

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Yep good catch... That looks alot like my 1-2 shift fork that came out of my trans. Is it all back together yet?

I finally got my last part I need for my rebuild (5th gear shift fork) and I should have mine done tomorrow. And back in the car sometime next week. Glad to hear you found your problem.
 
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