AA bearings.... the dilemma continues.

[Tim McC.]

My poor old AA is still giving me fits. Since I can't seem to keep a dual high unit operating, I've decided to switch over to a jackshaft. I found a good jackshaft unit, but unfortunately the bearings and sleeves are bad. The bearings are no problem, but the sleeves are. No one seems to have them and I haven't heard of any way to get around them.

Tom at Model A works hads thought about having to put a more modern bearing in the housing, but what kind should I consider? I know a tapered roller bearing would have to have a preload, so that's out of the question. My other option would be a one piece roller bearing, but what are the effects of that on thrust? Geez, I never knew how much of a headache this old AA could be! It makes me all the more thankful; for the repop suppliers of A parts, albeit even of questionable quality.

Tim.

[Buckwheat]

Tim,

I'm sorry to answer your post with more of a question, but I need to catch up to you guys and no one is responding to my post!!

You have the engine, through the clutch driving the normal transmission and a dual high unit between the transmission and the rear end. The "Jack shaft" I assume is to replace the dual high unit and connect the transmission back to the rear end.

Question: where and how many times is the drive line broken between the transmission and the rear end if any?

I thought the dual high unit was bypassed until you depressed the foot pedal to engage it?

How do you remove the dual high unit,, OR What has to be removed to get it out, transmission.....rearend?????

I have ordered some books that I hope will answer some or all of these simple questions, but I would appreciate a quick rundown.

BobbY W.
bwatson@kpmg.com

[Mike Taylor]

Tim,

I too have a dual high that I would like to replace with a jack shaft.
The dual trans. that I have is in the truck and seems to work ok, but when I put a fresh motor in the truck this summer I would like to replace it, because I do not believe I can get the parts to rebuild it.

Your post is confusing to me because my study of the parts book, and the jack shaft that I had shipped in, does not make me understand what bearings and sleaves you are referring to. Tom in Oregon knows a lot more than me about the AA, but I now am concerned that I have not gathered up the right parts.

It is my understanding that the jack shaft has a u joint on each end, is enclosed in a tube type thingy, and has end pieces that attach to the rear of the transmission and the front of the drive shaft. Bearings and sleaves do not show up in my understanding of what is needed. I hope your set up in unique, but admit that I may not know what I'm talking about.

I guess it is back to the books on this, and remember that this in fun.

Regards, Mike in south Louisiana

[Tim Mcc]

The dual high unit goes between the trans. and the rear torque tube. It is basically another transmission that has a direct drive and an underdrive that's operated by planetary gears and a sun gear arrangement. It is full of brass bushings and bearings, none of which are available, except for the outboard bearings... those are the same as in the torque tube for the driveshaft.

IN order to get the dual high out, you have to remove the rear end... much easier than the model A since it is only held on the springs by 4 bolts, and what looks like a giant main bearing cap. remove the brake rods and take off the u-joint cap.. . and roll the rear end out.

There is then another two large bolts that hold a flanged connector piece to the crossmember and another set of u-joint caps that connect the tranny. it's pretty simple to get out and once you'v done it 3 or 4 times, you'll get used to it.

As for the jackshaft question, it has 2 roller bearings in it, one at each end. If your jackshaft has a flare on one end and then a straight tube on the other, then it is correct. If you'll look in the end of the assembly, you should see a snap ring and below that there is a bearing and race just like ones in the model A water pump front bearing. The bearings again are the same ones that go into the dual high and also the top end of the worm gear rear torque tube.

in operation straight through, the dual high is directly coupled, but the whole arrangement is kind of bulky and rides on another roller bearing in the middle of the unit, also unavailalbe.

Grrrrr, and hope this answers some questions.

Tim Mc

[Bob C]

From looking at the parts book it seems the 28-29 coupling shaft has bearings in it and the 30-31 does not use bearings.
I don't know if the 30-31 will work in the 28-29.

[Buckwheat]

Good call Bob,

You are talking about the later '29 with the four speed and coupler shaft I assume. And you say in '30 they did away with the bearings in the coupler shaft. Hmmm I guess you wouldn't really need them in that short torque tube........

[Neil Wilson]

The 28/29 AAs with the 3-speed came with a coupling shaft with u-joints and bearings on both ends. As an option, the coupling shaft could be replaced with a dual high. It was hooked up the same way as the coupling shaft was.

The late 29 through 31 AAs came with a 4-speed. Until late 31 the coupling shaft had an internal gear at the front to mesh with a gear on the output shaft of the 4-speed. In late 31 there was a u-joint between the 4-speed and coupling shaft. Both coupling shafts had a u-joint at the rear and neither used bearings.

The late 31 coupling shaft could be removed from the truck with out removing the rear end or engine