Reusing cluster gears

[mcgarrett]

I'm pretty sure I already know the answer, but I'm curious if anyone has had any success with reusing transmission gears even if there is some signs of wear on the gear teeth but no evidence of abuse, broken teeth, shearing on the leading edges, etc. I have some extra cluster gears that look pretty good except for some signs of uniform wear across the teeth and I hate to discard them if they still have some life in them. They are worn, but when are they considered "worn out"? I'm curious to know if I can expect them to be noisy or will the cushion of new gear lube quiet them sufficiently. I don't normally install questionable used parts in anything, but cluster gears are so pricey these days, not to mention other transmission parts!

[JayJay]

McG - from what you describe, I would have no hesitation to reuse. Especially since new cluster gears are $350+, and you don't know where a new one comes from (one of the suppliers told me that his transmission gears come from Brazil)! If you have trouble, sounds like you have quite a few that you could keep on swapping out until you found one that works.

What seems to be still an issue with repop is the cluster and main shaft bearings. Has anyone found a reliable source of good ones?

[Banditorama]

It'll probably be noisey and if you have new gears on the other shaft, I'd absolutely replace it.

[mcgarrett]

JayJay,
I'm down to my last good pair of original cluster gear shaft roller bearings. Pate swap meet is coming up in 4 weeks so I'll be keeping an eye out for them. And thanks for your reply!

[Jim Mason]

https://jmodela.coffeecup.com/xmissionrebuild.html
Fwiw

[Gene F]

Sponsored Links (Register now to hide all advertisements)

Post #2 ✔, and ✔. I have been hearing about the cage bearings being not so good these days. Only thing is if ya wanna swap one out it's a lot of work.

[mcgarrett]

Jim M.
Thanks for the link. Great reference resource; I know I'll use it.

[w.michael]

In my experience, do not re-use cluster gear or any other gears if you paying someone else to do the labor. If it is your own car, and you do your own labor, and you have the time, re-use the cluster. If it’s not satisfactory, you only lose your own labor and time doing it a second time

W. Michael

[mcgarrett]

w.michael,
I do my own rebuilds, so as you say no big loss when it comes to my labor.

Thanks to all for your responses.

[Joe K]

My tendency is to buy about four transmission - and then combine them into one "reasonably good" transmission.

So needless to say there are a lot of parts "left over."

The other modus is to "buy everything new." Which works, but for me resulted in a transmission which I thought was "noisier" than the combined from used parts tranny. The "new" part machine quieted down after a while and the parts "wore together." But the used gear transmission was already there which may be the difference.

I would not combine new gears with used gears.

Quality of aftermarket parts IS a concern. And there is no way to really know. Used tranny parts are almost exclusively "original parts."

My best used start on a transmission was a transmission found at the town dump - obviously a discard from a "barn clean-out." That tranny was nearly perfect, except for 2nd gear the gear of which had worn to the point where it would pop out of 2nd unless you held the lever in place. Funny, that 2nd slider gear was worn out, but the corresponding teeth of the cluster were fine.

One wonders if the shifter rail grooves were wrong. I didn't think to compare at the time.

Joe K

[Bob Bidonde]

I have rebuilt and run several transmissions with used cluster gears. I have never bought / used a new cluster gear. To date, after thousands of miles, all is good using SAE 75W145 gear oil. A little noise can be quieted by adding STP to the oil.
However, I avoid using gears that have pitted teeth because the pits are usually fatigue failures (exfoliation).

[mcgarrett]

Joe & Bob - I tend to agree with your viewpoints. The bottom line is I'm not attempting to build a "perfect" transmission; my goal was to assemble a good, usable transmission from from used original parts for my own use. I was mainly concerned about what pitfalls I should look out for when deciding which parts were too used to be any good.

[Steve Schmauch]

Hello mcgarrett--All of the above is good information. Here are a some more things to consider in your building a good usable transmission. The transmission case is often overlooked. Jim Mason is correct that the FS Bulletins recommend "a few thousands" clearance on the cluster gear to transmission bosses. If you use two old cluster shafts to mock up the position of the cluster in the case you can measure the clearance with a feeler gauge. If it is much over 0.010" I would suggest making a shim. I make them from 0.005" stainless steel and adhere them to the back (small) end of the cluster with sticky wheel bearing grease prior to assembly.

The wear in the transmission front case bearing pocket is often overlooked. If the input shaft/bearing assembly slides into the case easily or worse yet "wobbles" in this pocket, it would be best to find another case. The best transmission case is one that the four retainer bolts slowly draw the input shaft/bearing assembly into the transmission case pocket. If this front bearing pocket has too much wear it is because of former alignment problems in the drive train components.

Jim Mason alluded to using sealant on the ends of the cluster and idler shafts. I think that is a good idea, as well as using sealant on all bolt holes that could leak out oil. This includes using sealant in the area of the shaft splines on the end of the main shaft area where the rear bearing is. This will prevent oil from entering the u-joint area.

Another thing to consider is using sealant on the u-joint clamp housing inner cup to fix the two gaskets from moving around during assembly of the drive shaft to the u-joint. I use the inner cup as a guide and mark areas to find out where to cut out portions of the bolt holes from the "universal" gaskets we get from vendors. I use a hole punch so the holes are exactly aligned and won't interfere with assembly. I use silicone sealant to adhere the gaskets to both sides of the inner cup. This makes assembly much, much easier! I use a whole tube of grease to fully encapsulate the u-joint.

[mcgarrett]

Steve S,
Your recommendations are very enlightening and educational. I probably would not have thought of some of them without your pointing them out. Many thanks for your response.

[rotorwrench]

Condition is everything on transmission parts. Bearings can even be reused as long as the parts still have smooth surfaces with no signs of pitting, grooving, or spalling. Gear teeth with a lot of wear start to groove a the point of first tooth to tooth contact. The tip of the teeth will get sharper as the surfaces wear. Pitting, grooving, or spalling of teeth as well as any chipping of teeth are not so good. The bearing bore dimension and condition of thrust faces also have to be good. If it all checks to be good then use it. If it lasted that long then it will go a good bit more. New reproductions parts are kind of an unknown unless a person can do hardness tests to insure longevity. I tend to trust a good used part more than a new reproduction part unless those particular vendor parts have been know to function well over time.

[Seth Swoboda]

I've got all kinds of Model A tramsmission parts. Listed them on the swap page and I get no interest.

[Synchro909]

I can't believe how tough these gearboxes are. When I took delivery of my 1928 Tudor from the US, the oil level was so low that the big gear at the front of the lower shaft was just dipping what oil was left. The teeth on every gear were galled and looked terrible. Given the price of getting stuff here and having just about gone broke getting the car here, I decided to flush out the sliver "sparkly" bits, refill with oil and see how things went. I didn't even replace the bearings. All of that was about 15-20 thousand miles ago and it still runs as quietly as any other, never jumps out of gear and generally behaves itself.
As for the OP, because I do my own work, I might use the gear but if I were paying someone to do it, I wouldn't dream of it.

[Pete]

I can't believe no one suggested one of the most important things to do when rebuilding used machinery.

MAGNAFLUX.

For those not familiar with it, it is usually done after the parts pass VISUAL inspection.
It is cheap and sometimes can be done at home.