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Attaching the torque tube to diff case
Hi all,  

I started to re-assemble a differential this evening and noticed that the fit between the torque tube and diff case is very tight.  All new bearings installed as the unit was in a real mess when I started.  In the photo you can see a bright spot as the outer bearing race is starting to bind as I push the pinion in to place  (it starts just on the pinion side of the oil gallery).  I can feel a very small lip with my fingernail at this point.  I think I can pull it in with the bolts but maybe it’s better to hone the lip out first.  Any thoughts?

I'm thinking that if I pull it in to position with the 6 bolts I'll be placing undue stress on the bearing.  I'm thinking it's better to have a firm fit and ensure the outer race is secure by some loctite. Again, any thoughts welcome.


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Steve & Tate Davidson
Perpetual Amateur Austineers
Other contributors know more than I do, but they haven't come along yet.

 I think the fit needs to be good - not tight, but pretty good - because it locates the pinion with respect to the crown wheel.

If there is an odd small irregularity, then scrape it off, but I wouldn't hone the whole thing.
Likewise I'm no expert. But I'm inclined to agree with Simon, I'd gently scrape, file or sand away any high spots in isolation rather than hone the whole thing. If it's rusty (doesn't look it) a quick swizz around with some very fine emery perhaps. You might consider warming the housing gently, tends to ease the fit.
Similarly my experience with diffs is limited and to the 1933 on type, but no experienced replies yet. The pinion bearing in its fully home position should be a good fit in the diff housing . (With a ball pinion this makes repeat removal to check mesh awkward. Have to peep thru the plug hole although some claim adj success with diff half assembled.)
The housing for the a/c bearings is in my expereince not normally a tight fit in the diff casing and need not be as lateral loads are modest . One of the a/c races has radial clearance for its outer ring; often find shims etc in an attempt to "fix" this!
As with the side bearings, care is necessary to get  a.c bearings the intended  way around and not apply pressure which may load, indent and ruin them.
If for some reason have to push hard on a ball race, beneficial if it rotated  whilst do so.
Warm the case and the bearing will drop straight in..... I rarely if ever fit or remove any bearings cold.
Black Art Enthusiast 
Assuming it is the fit of the main pinion ball race in its undistorted housing, you are fortunate. Often this race has been turning and is an easy fit. Dunno why, possibly chips wedge in it. Current external dia tolerance is generally slightly larger dia than historically.
If the balls and tracks are not rusted, pitted, or indented by chips, this is the only bearing worth the expense of renewing.
On cars often worked on, as the Seven, including by "mechanics", all manner of damage is likely. Vice marks, vice crush, punch burrs etc.
Thanks all for the words above, when I get home on the weekend I'll warm it up and have a go.
Steve & Tate Davidson
Perpetual Amateur Austineers

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