GMC Suburban Tranny 1989 - Need a Rebuilt

I have a '89 suburban, 3/4 ton, 2WD, 350 engine that has the auto tranny, which is slipping and disengaging. It probably needs to be replaced. I called the garage that does my major repairs, and the guy made some calls and said that GM doesn't have those trannys available anymore. He gets the GM ones if he can. So it looks like I'll need to buy a rebuilt one somewhere else and have him install it. Any recommendations? I know there are some good rebuilders out there, and some bad ones too. I want a gearbox that will give me some trouble-free years, and I hope to avoid the Mr. Transmission places.

jasper rebulds motors and trannys most garages are hooked up with them then thres e bay good luck oh and u might get a transmissoin shop to rebuld yours none are cheep

Gm does have the transmission part#8663983, hth

Get a master kit & rebuild it.

Local guy here rebuilds 700R4 for $700. He recently did my 4L60E for $900.

Dave, Suburbans are Notorious here in Texas for eating 700R4s in short order!
First of All!!!...........
#1..Get the Radiator pulled out have have it Serviced if it hasn't been out before now, then it is time! I will bet a Big Red Sodeee Water that your Radiator is somewhat plugged up and the increase in operation temp has helped to the demise of the tranny. Plug the in-tank-cooler holes! I think 3/8 pipe plugs are the size!
#2.. Go buy the biggest aftermarket Tranny cooler you can find. And mount it up in front of the radiator behind the Grill. Get whatever hardware and mounting straps needed at your local Hardware Store. Rubber hose and clamps at your Auto parts
Store.
You will be running the Tranny cooling system totally separate from the engine cooling system. This has been the biggest problem with GMs for Yrs. They ran the both together, but a small engine temp change that is not even noticeable to most folks will start a tranny to cook!
I did that with a 88, Chevy Sub(350/700R4) @ 150K and got it to go to 240K before it finely quite for good.
When the subject of GM Trannys come up......Tempature is Not Your Friend!
Hope this Helps.
Later,
John A.

my tranny expert loathes Jasper rebuilt trannys. He believes their mechanics are careless, they don't hire good people, rush them too much & use poor quality parts & no quality control.

The tranny on my 95 Burb was doing the same thing. I got the identical advice on the tranny cooler, that;s in the works, and a fluid flush, filter and refill. In the meantime I used the Lucas Tranny additive and it stopped what ever was sticking from doing so. Same thing happened in my daughter Grand Cherokee and Lucas fixed that too. Good stuff IMO.