I am looking to either rebuild or replace auto transmission in a 70 Cutlass S (4sp on the ctr console). I will probably outsource the transmission and am looking for a reputable shop in the central florida area preferably that deals with oldsmobiles. wondering a) does anyone have recommendations and b) for this transmission, are they typically rebuildable or is there a better swap that bolts up and makes more sense/reliable than a rebuild? the transmission in the car is original and shifted very smooth for at least 35 yrs so im inclined to stay with this transmission but wanted to get general concensus from the community.

 

I am looking to either rebuild or replace auto transmission in a 70 Cutlass S (4sp on the ctr console). I will probably outsource the transmission and am looking for a reputable shop in the central florida area preferably that deals with oldsmobiles. wondering a) does anyone have recommendations and b) for this transmission, are they typically rebuildable or is there a better swap that bolts up and makes more sense/reliable than a rebuild? the transmission in the car is original and shifted very smooth for at least 35 yrs so im inclined to stay with this transmission but wanted to get general concensus from the community. thanks for any input!

 

The origial automatic would have been a three speed TH350 trans. That's about the most common GM automatic ever made. Rebuilt units can be had for about $1000 or so.

 

I assume it is a T350 trans. very common, reliable and very rebuildable. When I lived in Central Florida, there was a place in Tampa that did pretty good work (not just swapped them out, but rebuilt yours), but that was 20 years ago...…….

 

Also you said 4 speed auto ? as the T350 are 3 speed.

 

Correction, 3 speed, i cant believe this is a 3sp but you are correct. Thanks for the clarification and thrilled to know this is a very common transmission. Im fine with the 3sp so sounds like a rebuilt t350 is the way to go. Im considering GM Muscle out of Hudson FL or RM garage out of Jacksonville. Transmission is the main issue but like to have some other items addressed as well.

 

If you remove/reinstall the transmission yourself and carry it over to any shop, it can be rebuilt for around $650+ the cost of a torque converter if you need it. Its not hard to R&R a transmission.

 

THM350 is a great transmission and I agree with the guys rebuild and keep or replace with equal.

THM400s are considered more reliable because they are stronger but they consume more power and are better suited to a big block. They are overkill on any stock Olds 350.

High performance G-Body 4 speed THM200-4R is the only alternative I would consider for a stock or stockish 350. But things need to be done to get it to work properly from what I understand, so not as easy as swapping in another THM350 but close. Probably worth the stretch if originality and minor tweaks don't bother you, as it gives a slightly quicker acceleration of the line as well as overdrive. Allowing you to put some relatively extreme gears in the rear end and still turn reasonable RPMs at highway speeds. But also more expensive to rebuild when the time comes from what I have heard...

The adage you have to pay to play is very much in our wheelhouse.