The Stovebolt Site Forums The Shop Area Driveline Transmission won't mount up

I'm replacing a 216 with a 235 in my 51 3100. The 235 came out of a 55 chevy Belair which had an automatic transmission. When attempting to install the original 3 speed it stop short by approximately a quarter of an inch of being fully seated. Can I trim that 1/4" Off the outboard end of the clutch gear which is just past the splined end. Any assistance would be greatly appreciated

Did you replace the pilot bushing?


From Rockauto.com:

DORMAN Part # 690034 More Info {#14651, 6900341} Inside Dia: 0.593"; Outside Dia.: 1.060"; Length: .751"
Only Used For Auto Trans Conversion; Powerglide to Manual Trans; O.D. 1.060"
Only Used For Automatic Transmission Conversion; Powerglide to Manual Transmission; O.D. 1.060"

It would be better to install the right pilot bushing, or drill the end of the crankshaft inboard of the pilot bushing a little deeper. The hole drilled in the crankshaft wouldn't have to be precise, just big enough for the end of the trans input shaft to move in a little deeper. About a 5/8" or an 11/16" drill bit in a variable-speed drill motor would do the job, but you'd need to remove the pilot bushing first. If you cut the trans input shaft off, no other transmission would ever fit and the next owner will have dirty words to say about you!
Jerry

Well isn't that just great! Three years ago, I bought the manual pilot bearing and had the OD turned down 0.030 for $40. It works, but I am now sorely missing that 40 bucks.
Rick, was there a pilot bearing in the end of the crank shaft before you tried to install the transmission?
The 235s that came with Powerglide did not come with a pilot bearing, and the hole which is in it is too small for a stock pilot bearing. It is common for folks to try whatever they can which will fit in the smaller hole and end up beating into place and crushing it, causing the inside diameter to be too small for the manual transmission input shaft.
Please get back to us when you figure out what's going on.
Carl

The pilot bushing ID is 0.593" and will accommodate the transmission input shaft with the OD of 0.588". I will most likely attempt to drill the hole in the crank a bit deeper. I will let you know how it works out. Thanks for the quick response.

When I measured the distance from the aft face of the bell housing to base of the hole drilled in the aft end of the crankshaft in the 216 and then did the same on the 235, the 235 hole was 1/4" shallower. Both bell housings dimensions front to rear are the same and a pilot bushing is installed on the 235. Thanks for the input.

Rick

Rick I tried to PM you but it says you're over your limit? If you get in a bind with your '55 auto 235 and need a '55 belair powerglide to make things work, PM me, I'm about 2 hours north.

I drilled the crank with an 11/16" bit to a depth of just shy of 1/2" and was able to get the 1/4" I needed to seat the transmission. It didn't take long but locating the 11/16" bit was a bit of a challenge. Thanks everyone for all the good info, this forum is awesome

good for you, yeah, I bet that was hard keeping it from trying to walk on you.