1984 700r4 transmission replacement

[Steve Hess]

My kids' 1984 automatic tranny gave up. I was told to replace it with a '87 -92 since they are less problem prone. Does anyone know if these are a direct replacement?
Also this car is an everyday driver not a collector so I would prefer to buy a good used one than to spend the big bucks for a total rebuild. Can anyone recommend a reputable salvage yard preferably on the left coast. We are located in Seattle. Thanks.

[Steve Hess]

Re: 1984 700r4 transmission replacement

BTW - The transmission operates OK except it makes a loud tap (knock) the faster you go. Like a card in the spokes of a bicycle. It doesn't do it while coasting, with no torque applied. Haven't been out of first gear either since this started. The noise is centered at about the tranny pan.
Anyone seen this before?

[Jim T.]

Re: 1984 700r4 transmission replacement

Check with GM parts about the availability of one of their GM rebuilts. I read somewhere once that their rebuilt transmissions are rebuilt with all the improvements made to that particular transmission in succesive years and you will have a better product than what you originally had.

[Joe L.]

Re: 1984 700r4 transmission replacement

Steve-----

I wouldn't even attempt to install a later transmission in an 84 without knowing for ABSOLUTE CERTAIN if there would be some compatibility problem. Unfortunately, I can't tell you, for sure, one way or the other.

If the later transmissions were compatible, then I would expect that GM would have, for SERVICE, superceded the earlier transmission with the later. They didn't though. However, they did supercede the 84 transmission with the 85-86. As Jim mentioned, GM rebuilt transmissions incorporate all possible later INTERNAL upgrades that can be incorporated into the original transmission. So, you "automatically" get an upgraded transmission that you KNOW will be 100% compatible with the vehicle that it's being installed in.

For the 1984 Corvette application, the current GM part number for a GM-rebuilt transmission is GM #24209718. This transmission carries a current GM LIST price of $1708.91 EXCHANGE ($250 core charge). However, this transmission can be purchased for about $1,100 EXCHANGE from competitive GM dealers.

I HIGHLY recommend going the above route rather than used. Just about the very last thing in the world that I would want is a USED Corvette automatic transmission. Who knows how it's been "thrashed" or how much life it has left in it? Plus, it's likely going to cost about $600-700, anyway. For the extra money you get a GM WARRANTY and a freshly remanufactured unit incorporating updates that you KNOW will work perfectly for your application. This is a "no brainer" in my opinion. Absolutely the ONLY WAY I would even consider going.

[Verle R.]

Re: 1984 700r4 transmission replacement

Steve,

I agree with Joe, under no circumstances buy a used transmission and install it. You likely will be pulling it soon. You would be better off getting your present transmission rebuilt by a good local shop...not one of the chain or cheap shops.

I also agree with Joe the best solution would be to get a GM rebuilt with warrantee. It costs more initially but you will be more satisfied over the long run.

I believe the transmissions are interchangable up to 92. As long as it has cable control it will work. The 91 and 92 transmissions are better than earlier 700s.

Pay attention to the tailshaft configuration and the speedomoter gears.

Verle

[steve Hess]

Good advice - Thanks everyone *NM* *NM*