The transmission in my stock 66 Skylark, ST300, is definitely slipping. Did the recommended procedure to tighten up the shifting per the manual. No change! put it in gear, floor it and the engine revs up and slowly the car starts to move out. Seems like slippage to me. Here's the question, better to rebuild the old two speed original to car or to seek out a rebuilt unit. I am aware that any rebuilt can be a can of worms, but down here in area I'm in nobody speaks Buick or switch pitch. Thought about going with a 350, but then again I have to find a shop that can do the swap, and correctly source the control cables, plus hooking it up to my AFB carb. Plus the cost of sourcing either a good used unit or a rebuilt. Don't suggest a 200r4 as that is way above my comfort level not to mention a rear gear change to make it work right. Car is a cruiser and doesn't see a lot of use.. Thanks for any input.
Other than the pump and the converter, the transmission is no different to rebuild. They are not some mythical super complex design. But to hear some transmission shops, you would think it was an armed nuclear bomb. If it's slipping, it never gets better, and once you do the WOT in the driveway, the clutches are BBR (burnt beyond recognition). Are you east or west of Nawlins, sha?
Rebuild - Did you try C&O at 4305 Bienville St New Orleans, LA 70119? looks like a old school shop. If not, ask around. It was used in Olds and Pontiac too, so old school speak is more important than "Buick"!
My normal answer is rebuild. But after mating my 340 with a TH350, I'm not looking back. But it has a low gear set and higher stall convertor. Makes a good engine perform great. https://tsirace.com/shop/ols/categories/t-350-transmissions (where I got the th350)
A 350 is about as easy a swap as can be. The same drive shaft, same bolt pattern, mates to the same cross member. All you need is the detent cable hooked up and that is actually optional if you are competent to pull it into 2nd when you want to drop a gear. It isn't that hard. It will make that car drive like new.
Retro-fit in the gas pedal with the TH350 trans kickdown cable from the 70-72 Skylark. Works great! Put the TH350 in it and drive on. The only thing I missed about the switch pitch 2 spd was the 2nd gear upshift at about 70mph! Lol
