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Oct 16, 2012 | 05:27 AM

#41

MikeM

Team Owner

Joined: Mar 2003

Posts: 26,118

Likes: 1,874

From: Greenville, Indiana

Quote:

Originally Posted by DansYellow66

Ball bearing front bearing. Would have been tighter (but not necessarily more durable) with a roller bearing.

I think that ball bearing would tolerate slight misalignment better than a roller bearing. On purpose.

Oct 16, 2012 | 01:34 PM

#42

JohnZ

Team Owner

Joined: Oct 2000

Posts: 38,897

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From: Washington Michigan

Quote:

Originally Posted by MikeM

I think that ball bearing would tolerate slight misalignment better than a roller bearing. On purpose.

I think the Tremec transmissions use a roller front bearing, which is why the concentricity of the input shaft and crankshaft pilot are more critical; we used the Tremec T56 in the Viper, and you couldn't grab and "wobble" the end of the input shaft like you can on a T-10/Muncie/Saginaw transmission.

Oct 16, 2012 | 03:10 PM

#43

MikeM

Team Owner

Joined: Mar 2003

Posts: 26,118

Likes: 1,874

From: Greenville, Indiana

Quote:

Originally Posted by JohnZ

To take a little further what I was getting at, I believe GM used the ballbearing on the transmission inputs shafts in anticipation of possibly a wide variation in their build process of the transmission relationship to the crankshaft.

The machining processes AND the ball bearing design would have been cheaper (cost save) than the latter method/design.

There was no need for precision machining or expensive bearings in the '60's. The clutches (many of them) would last 40-80K miles and when you replaced that, you stuck in a $.50 oilite bushing and both would last for the rest of the service life of the vehicle which typically was around 100k miles.

No reason that cheap little bushing isn't just as good today as it was back then as long as you retain the original component part design.

Oct 16, 2012 | 07:09 PM

#44

mike16

Racer

Joined: Jul 2011

Posts: 330

Likes: 2

ball bearings have been used by pontiac in manual and dual range hydra matic applications since the late 30's. and also by GMC. and in each case a bushing is also available.

If you have ever had to replace a hydra matic, to avaid having to do it again, you will want to install a bushing.

Oct 23, 2012 | 10:42 PM

#45

Plasticman

Race Director

Joined: Nov 2000

Posts: 10,340

Likes: 664

From: Beverly Hills (Pine Ridge) Florida

Ref. the below linked article on usage of pilot bushings, pilot roller bearings, importance of alignment, etc.:

http://www.crankshaftcoalition.com/w...g_and_bushings

Hopefully will put an end to the poor idea of using a roller pilot bearing with an older trans......but I doubt it.

Plasticman