Th400 in my car is toast. I'm torn between reman unit at $1000.00, used from salvage yard at $100.00, or buying an master rebuild kit for $100.00 and doing it myself. I've never rebuilt a tranny before, although I did recently remove and replace timing cover and two heads as well as install an electronic conversion kit on the distributor. I can do my own brakes and I replaced all the suspension components myself. So...now that you know my abilities, can I rebuild it myself? Any opinions? Otherwise, local salvage yard has 7-8 units for $100 w/90 day part warranty. Suggestions.
How do you know that your trans is toast? What symptoms does it show? This will let us know what kind of rebuild you may be looking at. I am in the process of doing a how-to/write up for V8buick on how to do a basic overhaul on a TH400. What are the areas/pieces to inspect, what tools you'll need etc. But that is still realistically 2 months away. Personally I wouldn't shy away from rebuilding it but auto transmissions are a different animal. I work with the new stuff pretty frequently and have gone through the odd stuff, 5spd NAG, 8spd and the basic TE/RLE or RFE transmissions. You'll want a large clean work surface to disassemble the transmission with good lighting and lots of time. You need to take your time if this is your first transmission, lay each piece out in the same direction/orientation that you removed it. Fan the pieces out like a deck of cards. Do you have a good camera to document the process for your own reference? Shops typically will want $400-600 to overhaul a TH400 out of the car. Even then, you have to trust that the shop overhauls all the components. Do you have a good dial indicator to measure endplay? The salvage yard price for a TH400 is pretty good but you'd have to consider that it is a core and you already have one of those. Best case scenario with the salvage yard trans is $100 for the trans, $75 in fluid, pan gasket and filter and it bolts in no problem. Remember you have to find either a BOP bellhousing bolt pattern or a multi bolt pattern bellhousing that has the chevy and BOP pattern.
You may have to fabricate or buy a couple unique tools for compressing clutch packs, but the rest is mostly typical tools and following the rule of ultimate cleanliness. For example, you won't be using shop rags or towels to clean parts prior to reassembly, only mineral spirits and compressed air. Between your Buick Chassis Service Manual and this book by Ron Sessions, you can do it if need be. Devon
Symptoms: all gears shift fine until about 30 minutes into the drive. Then I lose second gear. So when I start to move from stop I get 1.......then 3. No 2. I can get usually get it to go into 2 by shifting from D to 2, then I can go back into D and the car will shift back into 3. Otherwise, its 1....... then 3. Fluid is nice and red, doesn't smell burnt. It was replaced a year and a half ago...issue was present when I got the car. In addition to fluid change, I also replaced modulator. Fluid was normal color and didn't smell burnt when I first got it.
