Ring and Pinion Questions

[NikP]

I've developed a binding clicking sound and feel in the drivetrain under deceleration. I've isolated it to the rear differential since the noise and vibration goes away with the rear driveline removed. It's cringeworthy as I think any minute something is going to bind and pop.

I'm suspecting its ring and pinion alignment. I installed an air locker last year in this diff ('75 FJ40) and the instructions didn't call for checking patterns just backlash. I didn't check the pattern but now based on the binding click, I'm going to pull it out and double check everything.

Questions:
1. Assuming there are no chipped or broken teeth on the ring/pinion gears, is it possible to get an old ring and pinion within spec on backlash? (assuming I have a good pattern). I remember when I installed the locker, no matter what I did I couldn't get backlash to the service manual spec. I went with whatever I could get and called it good. Advice?

2. Any advice for getting an old gear set setup correctly if I decide to change out pinion bearings while I'm here? The locker install took care of all the other bearings so I might as well a make sure it's not an issue while I'm here.

3. I may opt for a completely new ring and pinion so I don't have to worry in the future. Where's the best source for a new gear for 4.10?

4. What else ahould I be looking for to identify my deceleration binding click?

 

[charliemeyer007]

So you drove it in 4H with the rear drive line out and the noise went away. Maybe there is some thing wrong with the transfer or the drive line. I would drain the differential and look for glitter first.

 

[Living in the Past]

Would feel the pinion flange for movement.

 

[shawnfj40]

At this point I would pull the third member and send it to East Coast Gear Supply and ask them to set it up correctly for you. If you never achieved the correct backlash and didn’t check the contact pattern, you may have wrecked that ring and pinion. If you are lucky they may be able to salvage something in there. I think you would just be throwing food money after bad by trying to toss more parts at it. Jmho

 

[NikP]

So you drove it in 4H with the rear drive line out and the noise went away. Maybe there is some thing wrong with the transfer or the drive line. I would drain the differential and look for glitter first.

No obvious glitter in diff. No obvious glitter in transfer. Correct me if I'm wrong but the gears engaged in transfer are the same between 2WD and 4WD hight other than the nose cone gets engaged to add the front driveline to the mix. If the problem goes away with more gearing engaged in the transfer that kind of points toward diff. Right?

 

[shawnfj40]

To actually answer your original question about backlash and old gears. Yes if you have and old matched set of gears it is possible to set them up correctly. For most differential carriers they are designed for specific thickness of ring gear. If yours was appropriate for your gear ratio then setting backlash should be no problem. There’s a lot more to it ie. bearing preload on the carrier etc… the only thing you probably didn’t need to be concerned with (maybe) was pinion depth. So long as backlash was good and your contact patch didn’t change. With an air locker you should not be getting any popping or binding from the diff. You didn’t be chance get your driveshaft out of phase did you?

 

[NikP]

You didn’t be chance get your driveshaft out of phase did you?

Nope, brand new Tom Woods installed directly from the box.

I'm going to pull the diff out and start investigating. I made an assumption pinion depth was good but I'm not sure if someone has been in the diff before so I'm going to check it all out.

 

[3_puppies]

you can get a good look at the diff by draining and removing the rear cover, without removing it

 

[NikP]

you can get a good look at the diff by draining and removing the rear cover, without removing it

I'm already at that point and can't see anything obvious. Going to investigate excessive backlash as a starting point.

 

[NikP]

Tore it down yesterday because baseline pattern test terrible. Backlash far from spec. Pinion bearing surfaces had seen better days. Definitely can see issues to take care of.

 

[charliemeyer007]

Yep, that needs work.

 

[NikP]

This pattern suggests remove shims. Is that right?

It had no shims when I took it apart. How can you correct this pattern if there are no shims?

Hopefully new bearings will give me a different starting point, so I won't worry too much yet but wanted to understand.

 

[pb4ugo]

Looks like used gearing according to dana. What's the backlash?

 

[NikP]

What's the backlash?

I think I was around .007 or .008.

That used gear pattern discussion is interesting. I’m debating whether to swap in a new gear or not. Worst case I try my best here and I can always swap in a new gear later. Not exactly sure what to do.

 

[EWheeler]

No obvious glitter in diff. No obvious glitter in transfer. Correct me if I'm wrong but the gears engaged in transfer are the same between 2WD and 4WD hight other than the nose cone gets engaged to add the front driveline to the mix. If the problem goes away with more gearing engaged in the transfer that kind of points toward diff. Right?

There is a great diff guy not terribly far away from you, I think he is in Ridgway. Member too. @RustyNailJustin


If I'm interpreting your first post correctly, you just slapped the old ring gear onto the chinese air locker and put it all back together without checking anything except backlash, which didnt meet specified tolerance? Did you re-use all your old bearings as well?

 

[NikP]

put it all back together without checking anything except backlash, which didnt meet specified tolerance? Did you re-use all your old bearings as well?

New carrier bearings were supplied with the locker. The instructions, (which are plagiarized from the ARB locker instructions word for word and including the pictures) only worried about backlash because the pinion depth won't change if you don't do anything with pinion bearings. If pinion depth and bearings don't change, then the only measure to worry about is backlash.

The backlash being out of tolerance is 100% my fault now that I've learned more. Thanks to all the input on the forum and elsewhere. I didn't set it correctly with the locker install.

So now the real question: Install the used gear or drop $300 for a new one? I already ordered new pinion bearings and the install kit from Cruiser Outfitters.

If I know what's right, I need to stop avoiding spending money and order a ring and pinion gear also.

 

[charliemeyer007]

If you put it together with new parts R & P set up correctly you will likely never need to do it again. If you use the parts you have now, maybe some day you will need to do it again. How much does $300 mean to you? its like 2 hours of shop rate, 4 tank full of gas.

 

[NikP]

If you put it together with new parts R & P set up correctly you will likely never need to do it again.

I know, I know... I just submitted the order. Sometimes I lose perspective trying to save a buck.

 

[pb4ugo]

Have you found anything that would contribute to the original issue? Clicking

 

[NikP]

Have you found anything that would contribute to the original issue? Clicking

One of the symptoms of excessive backlash is noise and possible binding. My error on setting backlash originally is likely the cause. I misinterpreted one line of the instructions originally and lacked the understanding I now have. My backlash was so far off it's embarrassing so I suspect that's the cause.

I had a driveline vibration long before all this and Tom Woods even went over the top to check my driveline a second time to ensure there were no problems. It leads be to wonder if I had some pinion bearing issues that only showed up with load. I'm hoping all this gets cleared up with new bearings and now having a proper setup.