Transmission Swap

I'm thinking of putting an automatic behind my '71 CJ5 225 cu in engine. Question? Will I be able to use any Buick design automatic? Such as, the Buick 400 turbo hydromatic. I have access to two priced at give away. I understand there was a GM automatic mated to the 225 in the late 60's and early 70's but have no idea where to find one. I'm sure someone has made the swap. Please help me get going in the right direction. kb71

 

Yes, the TH400 was used by Jeep in all theor ehicles from 1965 through 1979. There was an automatic behind the V6 in the Jeepster Commando. These transmissions were actually the Buick Nailhead case with a ring adapter to the BOP pattern (Buick-Olds-Pontiac, Cadillac too) though a BOP pattern transmission is equivalent.

However, the TH400 is pretty long for the CJ5. The TH350 works better (is shorter), and is a more efficient design to boot. More info on the Novak site: http://www.novak-adapt.com/knowledge/th350.htm

 

either would be a tough fit in an early 5.. makes for a long driveline in a short jeep... If'n ya got a '6 or a commando you are good to go..

BUBBA

 

What Tim said. Use A TH350. You are gonna have a shorter rear shaft but doable because with a V6 can also move engine forward also.

 

Thanks for the input guys. The TH350 looks like the way to go but more money, the TH400's are free and one is completely rebuilt, lacking only the short shaft. This is my third jeep rebuild. The first two were a '72 and a '75, however both were straightforward take-a-part, rebuild, put it back and paint it. This idea is a "Wonder if I can" and I might just leave it stock, except for putting on power steering which my son and I have already finished. Right now I'm doing an engine rebuild on the 225. Noticed also, that the frame is almost broken in half where the front of the rear spring hanger is attached. Since I have a nearly bare frame, would it be a good idea to just box the entire frame or would that cause the frame to be too stiff and not allow it to flex enough. Or would it be better to beef up the frame where the hangers attach. Thanks again. kb71

 

I completly boxed the frame on my 71 almost ten years ago with no adverse effects. Haven't had to weld around the spring hangers since.

 

Box frame is alot stronger and if you go with an auto trans in a cj5 you will definately have drive shaft problems. Way too long with the turbo 400, the turbo 350 is doable, but not recommended due to very short driveshafts and high pinion angles.