The Stovebolt Site Forums The Shop Area Driveline Transmission measurements

Working on mocking and fitting the transmission in my ‘62 C-10. I have a TH350 but would like a 700R4. Could someone give me the overall measurement from the bell housing to the end of the tailshaft on:

TH350 (various lengths?)
TH400
700R4

The 350 core I have seems a bit short but I don’t have it completely in place yet. I would like the longest one I can get to help with the driveshaft fitment. Help appreciated. Thanks

Martin,
The 700r4 I believe is 3 1/2 inches longer than a short 350 turbo. The 350 turbo came in 3 lengths, 6, 9 12 inches . I don't remember the length of a 400 but it is longer than a short 350. I will look for a transmission bok I have and see if I can find the exact sizes.

So the TH350 with a 12 inch tailshaft would be the longest option?

Yes, They usually came in Big station wagons. If you go looking for one, some have a multi bolt pattern ( BOP) buick, oldsmobile, pontiac. some have the chevy pattern also. May want to watch for the lock up torque converter also, it will have a electric plug on the driver side near the gear selector shaft, above the oil pan. If you find a 400 turbo, get the driveshaft yoke also as it is different than the others.

400 is not really on the table. Will the long tailshaft fit a TH350 that currently has the 9 inch shaft? If so is it a easy DIY project? I haven’t checked with the rebuilders in OKC yet to see what’s available.

To get the long shaft, the transmission will have to be taken apart and the shaft will have to be changed to the long one. It's not really complicated, but the transmission needs to be completely disassembled to change the tail
shaft.

Thanks Tommy, I kind of knew it wouldn't be user friendly. I'll just look for a long shaft already built.

Martin,
You need to be careful with the angles on the drive shaft and the rear end . Just adding or subtracting length could become a problem. What was the length of what you removed? I just measured 700R4 31 3/4, short 350 28 1/2 end of tail shaft housing to front of case . I would try to stay as close to what you removed in length. Don't think 3 inches would be much but 9 inches really make a difference with angles on the u joints.

Tommy, the problem is within the X-frame on the ‘62. The yoke originally sat almost completely up inside the X, thus, the new transmission has to come far enough through the frame hole so that the driveshaft when installed does not rub on the frame. My brother has a 700R4 in his ‘62 and does not have a clearance issue. I like that option because of the OD. I’ve got to get the engine mocked up so I can do some serious measurements. Thanks for your help.

Oh yes the old X frame, fought with that on my 62 impala. Seems like it was GMs flavor for the early 60s

You could also consider a more modern 4L60E from a newer pickup or G van. They are a newer version
of a 4 speed O/D with lockup converter. Much easier to find now than a older 700R4.
The recycle yards are full of them.
They were made with a one piece case or a two piece with a removable bell housing to fit different engines.
There is also three series of them.

The other 4 speed O/D GM that most folk ignore is called a 200 4R. they are a direct swap for a Powerglide.
Some think they are weak but they were used in Grand National Buicks, Monti Carlo S/S, and full size Caddys , Buicks & Olds.
I would love to put one behind a aluminum 6.0 Ls engine and swap the whole thing into one of our Volvo V90 wagons.

I have a 4L60 and a 5.3 from a 06 pickup that might go into my 62. My wife will then have a automatic to drive. Swapped my old Goldwing for it.

Happy wrenching.
Howie

Howie, I'm sticking my toe in water I know little about. But, what about the computer control needs of the transmissions you referenced above.

RonR

Exactly why I would prefer old school. No computer controlled anything on my truck. 700R4’s are plentiful around my neck of the woods.

Most are not direct swaps, there are some mods to the mount locations to the rear trans mount.

All custom fabrication so I will make it fit. Main concern was how far back into the X-frame the tailshaft would extend. Still working on mock-up.🛠