4 speed tranny rebuild question

[koanes]

Since the mainshaft and fourth gear assembly spins freely when the sprocket nut is tight, it must be that the gear is binding to the mainshaft when it is squared up to the race with the spacer. Never seen it before but maybe the the bore is crooked in the gear or bushing. That would explain why the gear would spin easily on the shaft before assembly, but bind when squared in the case. Another possibility, is the bearing and bearing housing on the other end of the main shaft fully seated. If it isn't in squarely that could cause a bind as well. Given that your main drive gear endplay in the race is on the tight side and I assume you fit the bearings to the gear and race on the snug side, it wouldn't take much to put you in a bind.

[oldsouthmcy]

The part has to be 35065-38.

Actually, either the 35065-65 or 35065-65B main drive gears will also work. The recess (indentation) did not get dropped until the caged main drive gear bearing was introduced in early-1977. The gear in your photo without the recess is either 35067-77 or 35067-84.

[bobdo]

Hi everybody, I don't know how many times I'll need to rewrite this. I keep hitting "reply to thread" & I lose my writing & have a fresh page.
I'll answer your questions, the sprocket recess is against the case side, only making contact with the spacer. The spacer & bearing are assembled correctly. I've studied this. The kicker side bearing & housing is seated firmly against the case. But, I didn't have the retaining plate screwed on, I can't imagine that would make a difference considering how it needs to be pressed on. I agree with you Kyle, the main gear is contacting the mainshaft splines with side pressure from the clutch side bearing area. All the parts are new & good quality. I'm beginning to think the problem might be the NOS bearing race on the clutch side. Has anyone had a problem with this? I know its built on the tight side, I might change the thrust washer from the .070" to the .065". I'm going to need to order new circle clips, the one I have is shot from putting the mainshaft in & out 3 times. Thanks, Bob

[Rubone]

Bob,
You mention the retainer is not screwed down on the mainshaft, ball race. Do you know for certain that the ball bearing is fully seated on the mainshaft and the nut is tight? If not it could allow the splines to contact the inner bushing in the main drive gear. It would not take much to contact.
Robbie

[bobdo]

Bob,
You mention the retainer is not screwed down on the mainshaft, ball race. Do you know for certain that the ball bearing is fully seated on the mainshaft and the nut is tight? If not it could allow the splines to contact the inner bushing in the main drive gear. It would not take much to contact.
Robbie

Hi Robbie,
I know that the bearing housing is tight in & against the case & the nut is tight with a tab bent against the nut. This is the kicker side. I just didn't tighten down the retainer plate against the ball bearing & housing. I've been following a few "how to's" to assemble this because its my first time. The progression doesn't show attaching the retainer plate at that point. But, maybe I should give it a try. I haven't had it in because I've been taking the mainshaft assembly in & out. Thanks, Bob

[bobdo]

Hello All,
I've also been on the Caimag forum trying to find help & a comment was made that I thought I would ask about here.
Here's the quote:
-"You finally found the source of the problem if you change hardened race and that you put new loose needle bearings inside that same race without line lapping ,then you have a problem, misalignment or rollers not fit to the race ( rollers size and out of round race or both),if you go that route you need to line lap the race to make sure the bearing in the kicker side and the hardened race line up perfectly,and then measure carefully and order the rollers you need to achieve perfect tolerance,if you did not do that you will have the problem you have" -

Is this always done when building a tranny with all new stock components, or just when there seems to be a problem like I have? I don't quite understand the need to "fit" the bearings when your buying all new & stock sizes. Why would it be different than buying a sealed bearing? I'm not combining any used parts in with new & my tranny case is great with no repairs.
I believe the comment was made by a very knowledgable person who was great to help me, I just don't understand.
Thanks, Bob

[T. Cotten]

Bob!

Often a gear does fit into a new race with fresh standard rollers, without line-honing or line-lapping.
Usually worms in the can would be if the previous race had shrank and spun, or any metal was shaved upon installation of the race, or weld repairs around it (such as the bottom stud hole), then the race bore will not be round or straight.

So frankly, I think Kyle suggested the most likely culprit: Your new Andrews gear should be closely inspected, particularly for width parameters, and compared to OEM. Although I have not handled any Andrews products in recent years, I remember many problems in the past. One that stands out was a mainshaft where one end was not concentric to the other, and would throw the box out of gear on a hard shift!

If the gear needs to be moved further outboard, then a thinner thrustwasher is the obvious way to do it. The resulting endplay can be taken up by lathe-cutting a shallow step into the spacer on the other side, allowing the gear to insert slightly, but retaining the hardened face for the rollers.

....Cotten

[bobdo]

Cotton,
There was no problem with the earlier race, other than being worn. When I installed it, I heated the case to 300 degrees & froze the race, it went in smoothly. The case has not been repaired & it gave me no problem earlier.
Maybe you & Kyle are right about the Andrews gear. Its hard for me to imagine, it looks like fine quality.
Thanks for your help, I appreciate it. Bob

[bobdo]

A point has been made that "back in the day" it was common to lap the races. Do you think that since I'm using NOS races that it was kinda expected & that they might not be true? Has anyone had a problem with that? Still troubleshooting.......Thanks, Bob

[koanes]

Bob, I f you stuck a new race in and didn't line lap I suspect the problem lies there. If the new race is fully seated in the case, the id is probably not concentric to the od and or shoulder. New races are not designed to be installed without line lapping and I occassionaly find that I need to lap to O/S bearings just to clean up the "shadows" that show from that same problem of things being out just a bit. I mistakenly assumed you were working with the original race. The gear would turn in the new race even if the fit was tight, but the gear bushing to mainshaft clearance is usually at around a .001, so if the gear was cocked just a bit the bushing would grab the shaft. The gear race od is 1.629 on a new gear, with standard bearings at .125 and .001 for clearance, the race id should be 1.880 and true.

[koanes]

Andrews products are very high quality, I use their cams and trans gears almost exclusively and haven't had any trouble since I got a batch of BT 4spd countershafts that somehow escaped the heat treating process. That got a little messy.

[bobdo]

Thanks Kyle,
I'll look for someone close by that can do it. Hopefuly they can just do the line lapping & leave the rest to me. I've been wanting to rebuild this tranny for the learning experience & boy I've been learning.
Thanks for your help. -Bob

[duffeycycles]

jims has pre-fit races

[indianut]

It may be Pre-Fit....until you PRESS it into a hole and it changes in size.

[T. Cotten]

Folks,
I have found JIMS products to cover the entire spectrum of quality as well: From the admirable, to the disastrous.

Bob!

Back to inspection, have you put your mainshaft between centers and inspected for any bend?
If indeed it is only a matter of interference with the splines, this may not be the culprit, but any stone unturned hides something ready to bite you.

And Folks,
Lapping is not the only way to fit a mainrace for rollers.
Just the most tedious.
You folks don't really think the Factory did it that way, do you?

And addressing the main drive gear itself,
A fresh-out-of-the-box part would hopefully be too tight to install, with final fitting expected.
Used mainshafts inevitably have some wear. This means the portion outboard from the load-bearing surface will be larger than the worn portion. Any overlap of the new bushing within the gear with the un-worn portion should be suspect to a possible bind.

(Whenever a gear with a fresh bushing is to be fitted to a shaft, it should be torqued firmly to a sprocket and spacer, to replicate final installation. The stress of the nut upon the sprocket and spacer splays the bushing clearance outward. A 'pre-fit' bushing', or one fitted without torquing, will be that much looser when installed.

....Cotten