You may recall my thread from last November where something broke in my transmission. This resulted in pulling the engine and tearing it down. Here is the earlier thread:
I found a frozen triple gear bushing, overheated thrust washers (blue) and a broken gear on the low speed drum.
I didn't get much done over the holidays, but I'm getting back to it now. I was fortunate to obtain 3 used low speed drums from a generous local T guy, of which I'll choose one and return the others. I'd like your opinion on which drum to use. Due to forum limits on # of photos, I'll post photos of the drums in succeeding posts.
I've cleaned (still need to clean out the gear teeth I know) and bead blasted all 3 and scanned them closely with a magnifier. I see no cracks in any of them. So they all appear to be usable.
Rim thickness: .135" - .143"
some gear wear, I'd rate it at #2 on a 1-3 scale.
Drum surface is good, but has a groove in the center (looks lime it was cut on a lathe for oil). The groove is .045' deep. .190" wide
Rim thickness: .132" - .140"
Gear wear I rate at #1 (best of the 3)
Drum surface: minor pitting at edge, .350" wide groove on web side, about .023" deep.
Rim thickness: .120" - .127"
Gear wear I rate at #3 (worst of the 3)
Drum surface: very minor pitting.
So, of the 3 drums - A, B and C, which would you choose and why?
My first choice would be "B" as it looks in the best shape in the photo. "A" would be my 2ed choice. While "A" has that deep groove you are only using low to start out from a stop unless you do a lot of driving in low. Between the two I would pick the one that has the least wear on the teeth.
"C" look to have oil migrating from some of the rivets, so they may be loose.
The gears are shot on all, there junk! Look for good ones.
B would be my choice. The teeth do have some wear on them but it has been running in for almost a hundred years to get to that point.
Kohnke, Iam with you the teeth are bad on all three. Its a lot of work to get to the tranny so why put in bad parts. Scott
Thanks for your input guys. I agree that "B" seems to be the best of the 3. But none are ideal.
The low speed drum gets more use and abuse than any of the three drums and should be the best. It is used for every start, some slow downs and panic stops as an aux brake. It should be your best drum for those three reasons and none of those three are quite good enough for the abuse it gets. The gear teeth are also worn a little more than most on all three drums.
Then too, one transmission that I rebuilt a few years ago had no reverse drum piece larger than a quarter, except the gear assembly. Reverse was only used for one panic stop and everything had been working fine before that stop was made.
A new gear and drum is well over $500, pretty painful. Perhaps an acceptable option is to find a good used gear and have it installed on a new Drum. Lang's has that option for about half the price of the new gear and drum combo. Are there are any good used gears out there or are they all worn like these?
Did you ask Lang's if they had a used one?
The gear on B looks best of the 3. The drum on C looks best of the 3 and the drum on A looks good. I've seen drums like A before and I think some aftermarket drums were made like that either to allow a place for the rivets to run without scraping the drum, or for an oil reservoir. I would have no problem using A, but if you want the gears to be quiet B would be better. Now if you want to spend a lot of money, you could take C and send it out to have the gear replaced.
Another thing to check very carefully would be all the other gears in the transmission. With those teeth missing, some of the other gears could be damaged.
I guess it all depends upon how much you intend to drive your T. If just a thousand or two a year and near home or on a tour with a trailer following any of them would be OK, but if you intend cross country trips and long tours without a trailer following, you should use the best you can afford.
I have not called Lang's yet, but I will. I'm putting together an order for them this week. This car is just for around town fun, I'm not really into the long distance touring thing. But obviously, I want it to be reliable. I don't want to go through this again anytime soon.
I would use "B". For "around town fun" you'll be just fine. I'm willing to bet that the Ts I drive the most probably don't have gears that good in them right now, (though they did when last rebuilt).