BobK

I rebuilt my transmission (well actually just replaced bearings/seals) this spring, and just recently started to drive the car again. The trans had approx 220k miles on it and I found the input shaft bearing was missing some of the cage around the ***** but all of the bearings were intact, and I just re-used the factory shims.

On my first test highway test drive the car popped out of 5th gear 3 different times, didn’t have any problems in subsequent drives. My daughter was driving the car last week and told me it had been popping out of 5th while she was driving. Shifting is smooth and I've had no grinding or other noises.

I never had an issue with it coming out of gear prior to my rebuild so I'm wondering if I may have damaged a synchro during my rebuild (didn't remove gears or synchros) or if it's possible that the detent spring is too week. Are all of the detent *****/springs the same size? The all looked the same size so I don't remember if I kept them in the same places.

96ItaliaSE

iTrader: (3)

im gonna bump you up to get the answer you need im weak in this area....have you checked your motor and transmission mounts are not loose or broken? the engine and transmission may be jumping around, knocking the transmission out of gear.
Also, check linkage rod/linkage cables to make sure they are in adjustment.

good luck

JtzMax

iTrader: (5)

You re-used the factory shims? Any particular reason? Most (not all) of the problems with the 5spd reside in the shims. The shims are the wrong size from the factory and prone to fail. This is why so many 5spds need to be rebuilt.

As for the detent spring being week, that is possible but I'd be suprised. If the syncros were damaged, you'd notice on shifts, so they are probably good. The IPS cage .... do you mean the collar of the bearing was missing spaces?

If I had to give any guess at all, I'd say it's a shim issue. Under load and heat, the shims may be just thin enough to let 5th be loose. Does it tend to do it under accel or just normal driving?

BobK

I figured it was shimmed right from the factory since I got over 200k miles before having bearing problems. I also got advice on these boards and from others that the shims should be fine if it got that many miles without the need for a rebuild.

I'm not sure what they call it, but I'm talking about the "cage" that holds the individual ***** . I found a couple pieces of the cage on the bottom of the transmission when I dis-assembled.

Strangly enough it tends to do it when just cruising, at least that's when it did it to me. I even tried flooring it and letting completely off of the throttle at highway speeds tying to get it to pop out of gear but it did not.

I pulled the center cross member when I removed the transmission to make it easier to get to the bolts. The mounts looked suprisingly good, but it's pretty hard to tell much with no pressure on them, the other mounts looked good as well.

I tried searching these forums for "popping out of gear" but didn't find much. The reason I asked about the detent ball/spring was becuase when searching the web I came across discussion about other types of vehicles having TIBs to replace detent ball/springs to cure the transmission from popping out of gear. But mostly I asked about this possibility because it seems like it would be the easiest to fix, and I hate to think about pulling the transmission and opening it back up so soon.

JtzMax

iTrader: (5)

Well ... I have a better understanding of just what you meant by "cage". Thanks! About the shims ... I guess if you got 200k outta them, they were ok untill then anyway.

Nealoc187

iTrader: (23)

That's not how it works. The shim thickness is selected based upon the overall height of the assembled shaft, which could have changed when you changed the bearing because of tiny differences in individual bearing thickness (as well as the other parts of the gearset, but in this case you didn't change anything else). This could change the required shim thickness - but it's unlikely that it changed it enough to have an impact on anything. It's more of an issue when you are changing lots of items on the shaft.

That said, I wouldn't worry too much about it now that it's back together. It's not as if the bearings are at risk of imminent failure because your shim is not the correct thickness. It's safe to assume that your shim is not too far off of what would be the "ideal" thickness and that you'll still get many tens of thousands of miles before it causes a problem. I wouldn't go tearing into the transmission now that it's back in the car just to change the shim.

The popping out of gear usually happens when a sleeve and/or the engagement teeth on the gear are worn down, it wouldn't have anything to do with the synchronizer. It is possible that the difference in gear stack height now was just right so as to make an already worn sleeve and/or the engagement teeth on 5th gear not quite fully engage and create the scenario you describe under certain conditions of throttle position, rocking of the engine, etc. I suspect that if you took the transmission back apart, you'd find that 5th gear and the 5/R sleeve are worn down.

Another possibility would be a little bit of foreign matter in the shift rail bore underneath the 5/R rail, making it so the rail can't slide as far as it normally should, again causing a scenario of the engagement teeth not fully engaging.

All the detent ***** are the same size so there's no possibility of you having put them in the wrong place.

JtzMax

iTrader: (5)

Neal ... that is a great post mate! Lot's of info there that should be helpfull to many .org members, me being one of them! I didn't think it would have anything to do with the syncros either ... but the tube being worn makes perfect sense. You're not really in R long enough to have it pop out, so it's hard to tell for certain w/o tearing out the trany. The shim issue is a question too ... but again, your theory holds more water. I agree the shim issue is pretty much a mute point for the most part at this time ... maybe 40 or 50k down the road it'll wear the bearings but ... that's a while.

Good info - we should maybe update the sticky to include things like this ... dunno, you're the mod!

Cheers!

Jim

dgeesaman

iTrader: (10)

Your shim sizes should be fine. Bearings are mfr'd to within a couple .0001". Shims need to be accurate to .002" or so. As long as you just pulled bearings and put in new ones you should be fine.

Your issue with 5th popping loose is possibly due to misassembled detente *****. I'll bet you simply forgot the last ball that goes in against the 5/R shift rail, before the long spring. That can be fixed without removing the tranny from the car. The ***** are all the same size except for the one that goes in the 5/r resist spring assembly. (That's the goofy looking stuff that gets put in first near the tranny magnet)

Dave