A very unhappy gear

Adam/Mill Valley CA

Adam/Mill Valley CA

Senior Member
Further to my recent post about a frame crack, the pictured gear is why I pulled out the ******. This is the reverse idler gear. I rebuilt the unit about 8,000 miles ago(old type pre-39 synchros gearset) with a new cluster gear, bearings, thrust washer, etc. but otherwise original gears, has worked perfectly with good shifting and no funny noises. Went to do a routine oil change and heard the "clink" of a couple of gear teeth in the pan. Surprisingly, everything else looked fine(cluster gear, low/reverse slider gear, etc) except for a disintegrating caged bearing at the front of the cluster gear.
Any ideas as to why this would happen-for now, I'm just chalking it up to "old age" of the reverse idler gear?
I've always shifted it carefully into low and reverse and there's no wear on the low/reverse slider to indicate otherwise

Adam
 

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Probably metal fatigue once a piece lets go it will take out the others in the caged area. You got lucky it didn't ruin the cluster gear etc. etc.. Go buy a Lottery ticket. JMHO
 
BTW, if you rebuilt it with "newly made" caged roller bearings, that may have been the issue. I do not know of any that are available that are correctly made - the "cages" are not anywhere near the quality of material and heat treat as Henry's originals. Take a fine file and see if you can file the edge of the cages - if you can, don't use them. Then take an original and do the same thing - you'll see what I'm talking about as far as hardness.

I only use good originals or NOS ones (if I can find them . . . hard to locate these days).

Also, the reproduction cluster and reverse shafts are junk - poor materials, not correct heat treat and .001 to .0015 undersize. Folks buy them - thinking they're doing the right thing and yet they are very poorly made. Use original cluster/rear shafts . . . good used or if you're lucky enough - NOS ones (which I haven't seen in years).

I actually made my own shafts for my 39 box in my 32 Cab. I used high-quality linear shafting material.
 
Thanks for the advice, I didn't realize poor quality roller bearings were such an issue, but looking around at various posts (both here and on the model A forum as they use the same roller bearings) it seems a real problem. I got these from Mac Van Pelt when I did the rebuild and I will try to contact him next week to see what he says, since he's forgotten more about these transmissions than most people know. I will need to replace the cluster gear shaft as it was roughed up a little where the bearing went south but I will see if he has a decent used one. Looks like NOS or NORS roller bearings are rarer than hen's teeth
jimvette I gave up buying Lotto tickets many years ago, maybe I should start again (!)

Adam
 
At some point in my earlier hot rod life I have broken every gear in the transmission, except the reverse idler. You should be proud!
 
Bored&Stroked said:
BTW, if you rebuilt it with "newly made" caged roller bearings, that may have been the issue. I do not know of any that are available that are correctly made - the "cages" are not anywhere near the quality of material and heat treat as Henry's originals. Take a fine file and see if you can file the edge of the cages - if you can, don't use them. Then take an original and do the same thing - you'll see what I'm talking about as far as hardness.

I only use good originals or NOS ones (if I can find them . . . hard to locate these days).

Also, the reproduction cluster and reverse shafts are junk - poor materials, not correct heat treat and .001 to .0015 undersize. Folks buy them - thinking they're doing the right thing and yet they are very poorly made. Use original cluster/rear shafts . . . good used or if you're lucky enough - NOS ones (which I haven't seen in years).

I actually made my own shafts for my 39 box in my 32 Cab. I used high-quality linear shafting material.
Click to expand...

I've had pretty much the same issue with those caged roller bearings I purchased some years ago. Lucky for me, I realized just how poorly they were made, and decided not to use them. I was also lucky enough to have a good collection of used original caged roller bearing, and used those.
Two of the best sources I've found for quality transmission parts are Mac Van Pelt and Michael Driskell, @ 3rd Gen Automotive.
 
Adam/Mill Valley CA said:
JM, I don't suppose you have any more of those "good used originals" just lying around??
Click to expand...

Adam, I'm sure I do have some....will take a look, and let you know via a pm. I've been doing a few conversions lately....putting the later '46-'48 transmission gear sets into '35-'36, pn 48-xxxx cases. Many of these '35-'36 gear sets I'm removing have low mileage, near perfect components
 
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