My transmission is kaput. I have a mechanic friend with a shop/lift who is helping me out with this project because it is beyond the scope of what I'm capable of and comfortable doing. In the past I had a slipping problem that was resolved by changing the fluid, filter, and repairing a leaking line to the cooler/radiator. I have strong reverse, but the forward gears are not doing much. This time the filter-fluid-flush didn't fix the problem and my mechanic says it's time for a new transmission.

We've been unable to locate any identifying information on the existing transmission that has been useful to a GM dealer in order to order a transmission that has some sort of warranty. Mechanic friend says I should buy a TH400 from TCI. I see that some folks have talked about swapping to heavy duty transmissions like the 4l80e, but I don't think the 4th gear/OD is worth the added cost. Any suggestions other than the TCI TH400? Very fast and reputable rebuild shops?

Got a guy here in Iowa that will rebuild the TH400 for about $800 does not do you much good, he rebuilt one on my old winne and it was fine That was with he pull and replace.

I used Suncoast Converters and Webb Transmissions in FT. Walton Beach to rebuild/uprate my 4L80E, and they did an exceptional job.

Sometimes it's worth crating something up and shipping it to an outside shop.

But there surely must be reputable shops in NY.

Monster transmissions in Florida. Free shipping, upgraded shift kits, stronger clutches. Check on web. Warranty.

I went with a Jasper reman swap.....never had a minutes problem with it and thought I received good value vs cost.
On the flip side,there’s also horror stories out there.

what part of New York are you from?

I put a reman TCI TH400 and torque converter in my 86. Very happy with both. Less slip in torque converter about 50 rpm less at same cruise speed. Good solid shift points too