Trans Gear Cluster Bearing

firetique57

firetique57

Senior Member
I'm rebuilding a transmission and the gear cluster needs replaced. I have one I got from an older Model A'r and he had a note on it that says "uses 3 bearings no spacer" He's no longer with us and I've searched and can find no mention on a Model A gear cluster with three bearings and no spacer. Can anyone enlighten me or should I just go ahead and use the new bearings I have with the spacer?
 
I have heard of using three bearings and no spacer. Even Brattons mentions it in their catalog. But I've never seen it done, nor have I seen the end result after thousands of miles. It might work in an original cluster gear, but in the repro clusters, if I remember correctly ( a big if these days, I admit) the center is not machined as a race, just the ends, so a bearing in the center would just be an expensive spacer.
 
I agree the spacer seems the appropriate way to go. In looking down the inside shaft of the cluster gear that is bad (pitting) the area where the spacer should go has two pieces of metal that appear be part of the shaft i.e. won't come out. I tried to tap it out with a punch and it won't budge. It also appears the two pieces are on either side of the oiling hole. It had a short and long bearing in it just no spacer.
 
It sounds like you have the gear that takes no spacer. It would also not be possible to use 3 bearings with this gear.
 
Early cluster gears did not use a spacer it was built into the cluster. Look inside where the bearing goes and see if there is a stop in place to keep the bearing from moving.
 
yep, you have an early gear. A simple decision.


firetique57 said:
I agree the spacer seems the appropriate way to go. In looking down the inside shaft of the cluster gear that is bad (pitting) the area where the spacer should go has two pieces of metal that appear be part of the shaft i.e. won't come out. I tried to tap it out with a punch and it won't budge. It also appears the two pieces are on either side of the oiling hole. It had a short and long bearing in it just no spacer.
Click to expand...
 
I've done the three bearings (two long and one short) and two bearings (one long one short and a spacer)

I have not seen difference between the two in functionality or life - well life is still indeterminate, and will probably be so during my lifetime.

The three bearing was done on a transmission which was found on tear down to have brinnelled the smaller bearing (at the large end of the gear) which was in seriously tough shape. Funny though, the gear was fine, but the shaft had worn out taking (apparently) the bearing with it.

I usually machine a groove in the outboard end of the reverse idler and cluster gear shaft idler to seal the case juncture with an o-ring. This to get past a little drip from this location (which is sealed by the aftermarket kit/cover)

Some of these shafts are QUITE hard - to the point where they laugh at high speed steel - or even carbide. (I felt bad when machining the new cluster shaft broke my machinist friend's carbide tool bit worth probably $30 at the time.) We ended up cutting the groove on that one using a tool post grinder and a fairly thin wheel.

The brinnelled/failed cluster shaft seemed to have been case hardened, and the brinnelling went through the case hardening. As I didn't do any machining on a worn out shaft, I don't have comparison on hardness of this one with a modern shaft.
 
John LaVoy said:
Early cluster gears did not use a spacer it was built into the cluster. Look inside where the bearing goes and see if there is a stop in place to keep the bearing from moving.
Click to expand...


The early cluster gears had two washer looking devices with a collar on them that was pressed down into the bearing tunnel from each end to properly retain the two roller bearings.

When I go to use an early cluster, the two spacers are easily knocked out with a punch and I install the later sleeve spacer. Reason being I want to properly clean out the bearing tunnel and it is difficult to dislodge wear particles that have imbedded around the two spacers.

I have taken several transmissions apart and found a third roller bearing in place instead of a spacer. Henry designed the transmission such that two roller bearings were enough to carry the load of the cluster gear.

I can't see where it would hurt to install a third bearing, but I doubt there is any benefit in doing so. When I rebuild a transmission I install the two bearings Henry ordered and the later sleeve spacer (I have a whole box of them). To add the third bearing would cost another $6 - $8.

Tom Endy
 
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