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Small reverse gear only has a chip all the way around in the center from passing a chunk of tooth through the set as far as I can tell. The rest of the gears look fine.
What else do I need to check while I'm in here? I'm planning on replacing the large reverse gear and replacing the synchros.
No synchro in reverse. Dual disc clutches which people have a tough time getting to release properly. Thick gear oil, which makes the transmission keep spinning, internally, especially when cold. Drivers that don't understand any of the above, start the car and immediately shove the transmissions into reverse, without allowing time for the pieces to quit spinning.
All of these things cause chipped reverse gears.
Good luck finding a new reverse gear. I think it's been about 15 years since they were available....
"Synchros" are not the only problem and most (almost all) of these transmssions do not get "repaired" when the novice goes in and replaces only the synchros.
Study and understand that while the synchro does "absorb" roughly 65% of the wear, the slider that rubs against the synchro "absorbs" about 35% of the wear. Blindly replacing the synchros without understanding how the whole thing works and ignoring the wear on the slider is what backfires on almost every single "home" rebuild.....and many "professional" rebuilds.
There's some serious knowledge/tricks to these things, to make them work properly.
The "early" transmissions (up to about 1983) had a symetrical slider in 1st and reverse (pointy teeth on both sides), even though the teeth on reverse were never used (no synchro in reverse.)
Simply flipping the slider over and using the teeth that have never touched anything will give you brand new teeth for 1st gear! That's one of the "tricks".
2nd and 3rd gear almost always, at this point in time, need a new slider.
Frequently, 4th and 5th have such little wear on the slider, a new synchro will solve any problem they will have, for the next 80,000 miles.
There's another thread going with similar questions....let me see if I can figure out how to describe/take pictures of how to determine what is worn and needs to be replaced, versus what is worn and will last through another rebuild.
You never know, they buy parts from places going out of business and sometimes end up with NOS pieces. I wouldn't hold my breath.....if I knew they had one, I'd have snatched it up in a heartbeat. With-in the next year or two, I'll be making both of the reverse gears....getting good used ones has gotten very tough.
...and you're telling me this rebuild just got even more expensive with the sliders.
I am telling you that if you don't pay attention to the sliders, you will end up with the typical "rebuilt" early transmssion that either grinds when it is first done or grind after the high spots on the new synchros are worn away.
I'm also telling you that you can usually get a brand new slider surface on 1st gear about 95% of the time (because people are clueless that it can be flipped over), but the majority of the time 2nd and 3rd slider won't be adequate.
Does the shop manual have measurements for the sliders like it does for the synchros?
The shop manual doesn't mention checking the sliders for wear. Which is why almost everyone misses this important detail and ends up severely disappointed. It's been one of my little secrets, for years.
Any transmission that only needs syncros and a slider or two is a cheap rebuild. Get a price on that input bearing on 5th gear....or a new 1st and 2nd gear set (needed when those pointy teeth get worn too badly), if you really want to get an idea of what it can cost.
The main wear surfaces are the shift couplings/sliders and synchros, anything else to look for?
Any opinion on me just reusing the reverse gear I have? I haven't had any grinding out of it, however I've issues with the car wanting to slot into 2nd rather than reverse. I had attributed this to poor adjustment of the shifter after replacing bushings, but I might be wrong.
What else do need to check while the transmission is out? I'm planning on inspecting and replacing the CV join boots.
Any transmission that only needs syncros and a slider or two is a cheap rebuild. Get a price on that input bearing on 5th gear....or a new 1st and 2nd gear set (needed when those pointy teeth get worn too badly), if you really want to get an idea of what it can cost.
thats been my luck as well.
what is the technique the reverse gear gets engaged on the OBs? the slider just fits into the gear teeth itself.... thats why the side of the reverse gear gets chewed up?
i wouldnt worry about that reverse gear... if you wait a little longer or use another synchro to slow the drive shaft down to a stop.. the slider will mesh perfectly and those gears stilll can do the job. (as long as you got all the pieces out.
my first rebuild in 88 looked like that... it never was a problem
I don't know if the clutch master piston/spring modification was the actual cause of the improvement, but after the mod my GB rebuilt gearbox would go into reverse immediately after start or a stop of forward motion without ANY grinding at all.
Prior to the mod, I gave it a 5 second count before shifting to reverse to prevent any clashing.
12-06-2015, 06:49 PM
1982 5-speed Transmission Rebuild: Chewed Reverse Gear
