1982 transmission: local rebuild vs. send off to a remanufacturer

[Harris B.]

I could use some advice. My 1982 with 23,000 miles is beginning to have transmission troubles. It seems to slip or chatter once it gets into the highest gear (torque converter?). There is a slight transmission fluid leak as well. I suspect it is time to have the transmission rebuilt. However, my guess is these transmissions have not been around since the early 90's and I doubt many local transmission shops work on these. I also have the impression that these remanufacturing shops probably do a better job at rebuilding than a local shop simply because they do it all day long. The problem with the remanufacturing shops is that you still have to remove the transmission from the car, ship off the transmission for rebuilding, and then have it shipped back and reinstalled.

I would like to have my existing transmission rebuilt rather than purchasing a rebuilt one. One remanufacturer I spoke to told me that I would have to send my core to them as it would be difficult for them to locate a core for rebuilding. If I did that, they assured me none of the date codes or serial numbers would be removed.

So, here is my question: would you take the car to a local shop to have the transmission rebuilt or would you send it off to be rebuilt. Any suggestions or comments would be welcome.

[Richard G.]

Re: 1982 transmission: local rebuild vs. send off to a remanufacturer

Yes, the local shops do work on them!
I would trust most the shops in my area. Check the yelp reviews if it helps your confidence.
The old transmission are like old motors, easier to work on than the modern stuff.
Be adamant about keeping your old one and write down the tag numbers just to be sure.
(Always do this what ever you send out)

Could be the torque converter as the early lock-ups had issues with the converter clutch locking up smoothly..

If you have the TH350-C it was produced with the lockup torque converter late 1979 model year, and was produced through 1984

You can identify any converter issues from transmission internals issues by just stepping on the brake pedal enough to switch on the brake lights but not enough to slow the car down. Do this with your left foot while keeping your right foot on the gas (without moving the throttle)
If the shuddering quits it's in the converter. Their several methods to repair this issue. The transmission shop would be better at diagnosing the issue and the best fix.
Rick

[Tom R.]

Re: 1982 transmission: local rebuild vs. send off to a remanufacturer

I could use some advice. My 1982 with 23,000 miles is beginning to have transmission troubles. It seems to slip or chatter once it gets into the highest gear (torque converter?). There is a slight transmission fluid leak as well. I suspect it is time to have the transmission rebuilt. However, my guess is these transmissions have not been around since the early 90's and I doubt many local transmission shops work on these. I also have the impression that these remanufacturing shops probably do a better job at rebuilding than a local shop simply because they do it all day long. The problem with the remanufacturing shops is that you still have to remove the transmission from the car, ship off the transmission for rebuilding, and then have it shipped back and reinstalled.

I would like to have my existing transmission rebuilt rather than purchasing a rebuilt one. One remanufacturer I spoke to told me that I would have to send my core to them as it would be difficult for them to locate a core for rebuilding. If I did that, they assured me none of the date codes or serial numbers would be removed.

So, here is my question: would you take the car to a local shop to have the transmission rebuilt or would you send it off to be rebuilt. Any suggestions or comments would be welcome.

Richard offers some great tips and I would just add a few of my thoughts, owning a 78 THM 350 and one also sporting a leak, I believe and have assessed between the torque converter and engine. Your automatic is probably a THM model 700-R4, a four-speed automatic transmission. The 700 was installed in 82 Corvettes while the THM 350 (three-speed automatic) was equipped in 78-81 Corvettes. But as Richard points out, check and document the VIN derivative along with the tranny assembly code. They are stamped (bar coded?) in 82.

I have found that local shops, their transmission mechanics are old-school types who know their stuff but do your homework. Find some local shops that have been around awhile and go to the shop, asking about who does their work and whether they work on THMs. This is certainly a lot more convenient than shipping it out somewhere. But your point is well taken...dedicated transmission shops, old school, do a lot of the same thing, have parts or parts access and know the drill. If I were to take this on, I would removed and drag to a Corvette event like BG or Carlisle, or even a local regional event where the vendor mechanic has a presence. In effect, hand delivering the unit and picking it up the same way.

So I'm looking at the seal that is leaking up by the torque converter and my plan is to take it to the local shop who will replace the seal, not necessarily a total THM rebuild, I trust the shop who do quite a bit of work for me on other vehicles. They would then be simple removing the THM, removing the torque converter, replacing the seal and reinstalling.

Hope this helps.

[Edward J.]

Re: 1982 transmission: local rebuild vs. send off to a remanufacturer

Harris, I was a GM tech back in that era and can tell from memory the 700R4 transmissions were troublesome at times with so many updated parts. There was a O-ring style seal on the end of the input shaft the when it does not seal caused a chatter with the lock up, that along with a fluid change would be were I would start. it still requires the transmission removal and its one of the easier transmissions to remove on corvettes. after all these years if the trans has operated and shifted through the gears why mess with a good thing, all great info above, and if your testing does show its the lock up portion go with this repair, maybe someone has a Tech service bulletin on this problem. You are correct about just letting anyone rebuilding these transmissions.

[Richard G.]

Re: 1982 transmission: local rebuild vs. send off to a remanufacturer

Tom is correct, you likely have the 4L60 or what was know back when as the 700R4.
I believe this was the only transmission for 1982.
1982 is the first year for this transmission and in its early years was not very reliable. That may be an understatement.
Proof is your car doesn't have many miles and the transmission requires work.
The torque converter seal rarely leaks unless the pump bushing has lost its fit in the pump.
Just a caution not to jump to conclusions.
There are many other seals in this area so its an difficult one to identify because of access. I have observed torque converters hubs crack and leak.
Replacing the converter isn't necessarily the shutter fix. There is a valve that controls the lock-up that has wear issues.

I like to keep my cars all stock and I understand your quest to do so. Is it a driver or mostly a show car?
If it's a 1982 driver and the transmission required rebuilding, I would replace it with one from a 1987-1992 Corvette.
GM made major upgrades to this transmission in 1987 and they are a way better transmission.
The book, with the changes made to this transmission, is almost as large as the original rebuilding manual.
Keep the old one if you are interested in returning it to stock some day.
Cheers
Rick

[Harris B.]

Re: 1982 transmission: local rebuild vs. send off to a remanufacturer

Everyone, thank you for your excellent comments. Extremely helpful.

Harris