Pinion shaft vs bearing. 555-520

[135sohc]

Does the shaft fail from abuse and take the bearing with it or does the bearing go to crap and take the shaft with it ? I picked up a 520 today and got it broken down to the bare case. Front pinion shaft/intermediate shaft bearing and the surface of the shaft looked great vs all the horror and carnage pictures posted by many here. Not new by any means but nowhere near nasty.

Transmission came from a 2.2 T1 Daytona. Overall decent condition (good rebuildable core) but it was evident its been given some hard usage in its past (3-4 & 5th fork pads were torn up, synchronizer teeth were slightly rounded on 3 & 4 ect)

[turbovanman²]

Probably both, one starts to pit and the rest is history. When I used to rebuild T5's, they did exactly the same thing, the input shaft rode on the output shaft with loose rollers, they'd wear, we figured due to dexron, and all surface's and rollers were buggered.

[135sohc]

I forgot the best part and your posting reminded me.. This thing had ATF in it !!! looked and smelled like old a** dirty as hell dexron.

[tryingbe]

Lucky. Mine smells like gear oil...

[black86glhs]

I forgot the best part and your posting reminded me.. This thing had ATF in it !!! looked and smelled like old a** dirty as hell dexron.

better than old --- 7176 type...lol.

[135sohc]

Me and another member have been doing some digging and so far havnt come up with a decent solution to replacing the OEM koyo 12 roller bearing with the noticeably inferior Timken/Torrington 5707 which has an extra roller, not as wide and does not have anywhere near the HD'ness of the koyo bearing. Looking at doing a shim setup to position the bearing further out in the case so its riding closer to the center of the shaft roller surface. But will have to see how that will affect the oil feeder setup and its proper operation.

[MiniMopar]

It's the shaft that fails, I'm pretty sure. I had at least one A525 with a good bearing and cracks on the shaft surface. The hardening is not deep enough to be a bearing surface like that. Surface fatigue sets in, cracks form, and the surface falls apart. That's why they added the inner race in the A523 and later trannys. High-boost abuse probably accelerates the process. But...there's not much that can be done about it. I've tried to find a bearing with an inner race that has similar ratings, can fit the case, and can fit on the shaft without serious modification. No luck. It's kind of a weird size, I think.

Maybe someday, someone with the right resources at their fingertips can find something.

[Reaper1]

The thing is that even with the pressed on race of the 3-plane trannies, they still have issues. Manly the race coming off the shaft.

I don't know anybody who's pushed a repaired shaft hard and long enough to see if those hold up. (by "repaired" I mean the way Simon's guy does it by machining down the shaft and pressing on a hardened steel race, NOT welding).

[MiniMopar]

I haven't had that happen to me, but I know it does. The only thing I can think of to explain that is the shaft not being parallel with the bearing. The rollers would be at a slight angle to the race and could slowly pull it off. When I replaced the race on mind, it required a a lot of force to press it on. Way more than any other race in the trans. I was afraid it might crack.

[mock_glh]

I haven't had that happen to me, but I know it does. The only thing I can think of to explain that is the shaft not being parallel with the bearing. The rollers would be at a slight angle to the race and could slowly pull it off. When I replaced the race on mind, it required a a lot of force to press it on. Way more than any other race in the trans. I was afraid it might crack.

I don't think that's what causes it. I've had it happen a few times and I think it's the hard launches at the track that do it. The helix angle on the ring and pinion create side thrust that will push the race off. Luckily (if you want to call it that) it will rub through the case and start leaking oil before it comes completely off and causes major carnage. The resulting hole can at least be plugged. A stiffer end plate for the 523/568 trannies could be the remedy (or a straight cut ring and pinion).

[135sohc]

Yes I started an interest thread on possibly getting a stronger/slightly thicker bearing plate for the 523/568 and got crickets for the responce...

[MiniMopar]

I don't think that's what causes it. I've had it happen a few times and I think it's the hard launches at the track that do it. The helix angle on the ring and pinion create side thrust that will push the race off. Luckily (if you want to call it that) it will rub through the case and start leaking oil before it comes completely off and causes major carnage. The resulting hole can at least be plugged. A stiffer end plate for the 523/568 trannies could be the remedy (or a straight cut ring and pinion).

I can't quite visualize how that would happen, since the race floats freely side-to-side the bearing. The rollers can't really create any side force on the race. Also the thrust from the helical pinion gear is somewhat cancelled by the opposite thrust from helix of whatever gear you are in. The rest is handled by the ball bearing at the small end of the shaft (that's why it has a snap ring around the outside). The input shaft is what creates all that thrust on the end plate, because it only has the main shaft to mesh against.

[135sohc]

Check this out... http://www.applied.com/apps/commerce...=a&mp=NKI42/20#

Local napa referred them to me. http://web.applied.com/

[onerippinturbo2]

that looks friggin awesome. just gotta see how we go about getting them after measuring up intermediate shaft diameter.

[black86glhs]

What are the dimensions of the 5707 bearing? I have a Koyo RNU070618 bearing and want to compare.

[cordes]

Check this out... http://www.applied.com/apps/commerce...=a&mp=NKI42/20#

Local napa referred them to me. http://web.applied.com/

I missed roller bearings 101. What am I looking for here that's better than what's out there now?

[135sohc]

That is just an idea. I dont know if that bearing is anywhere near heavy enough to withstand the impact/shock loading from the ring/pinion wanting to push in opposite directions from eachother.
It is the correct OD and Width to fit into the case but the shaft would need modified to let that work at the very least. It is the same idea of the bearing and race setup on the 523/568 so the rollers arnt riding directly on the shaft chewing it up and your not having to cut more metal off the shaft and install the fixing collar idea.

[cordes]

That is just an idea. I dont know if that bearing is anywhere near heavy enough to withstand the impact/shock loading from the ring/pinion wanting to push in opposite directions from eachother.
It is the correct OD and Width to fit into the case but the shaft would need modified to let that work at the very least. It is the same idea of the bearing and race setup on the 523/568 so the rollers arnt riding directly on the shaft chewing it up and your not having to cut more metal off the shaft and install the fixing collar idea.

Thanks. I see what you're getting at with that now.

[black86glhs]

I have something on order, but won't be processed until next week. It may not even be the correct part. However, I felt it was worth it to see if it the part I was looking for. When it shows up and if it is the correct part, I post up what I came across.

[Reeves]

Check this out... http://www.applied.com/apps/commerce...=a&mp=NKI42/20#

Local napa referred them to me. http://web.applied.com/

Anyone try it?