Locker & Regear Saga, Part 3: Dana 35 Gear Setup & Overcoming Issues
No, I didn't give up
. I ended up losing a few days of progress due to running into some issues related to the gear setup. I was having a hard time making sense of it and decided I'd consult with our gear expert,
@Rob5589. Thanks to his help we were able to sort out the problems and I was able to continue with the gear setup.
The OEM gears had the pinion depth shim behind the inner pinion bearing. To make my setup easier I needed to measure the thickness of that shim so I'd have a starting point to work from.
I've got an eBay version of the
Yukon bearing tool, it sure makes quick work of removing pinion bearings! The eBay one seems to be exactly the same, likely made in the same factory, and is much cheaper, especially if you use an eBay coupon in addition
Before I began to setup the new gears I needed to measure all of my shims and note their thickness. It is crucial to be accurate on this step and use a micrometer as some of the shims are as thin as .002", and that will make a difference in the final setup.
In addition to my Revolution shims I also got a set of
Yukon Super 35 shims for the carrier. The Eaton E-locker instructions claimed that in addition to specific bearings, I'd also need special shims. Well, I'm not entirely sure I actually needed these, as the Revolution shims appear that they would've fit fine, but they are nice shims and since I had them I used them!
Next, I drove out the old pinion bearing races and prepared to install the new ones into the housing.
The outer race is just driven into the housing. When I installed it everything felt and seemed good, but it actually seems to have been the cause of one of the issues I ran into. I'll explain that later.
My Revolution install kit includes pinion depth shims that go behind the inner bearing race, so prior to installing it I created a starting depth shim stack. Note the shims pictured are for the carrier, they were just handy at the time
Now I was able to press on my new inner pinion bearing. I didn't have anything around the garage that would fit over the pinion to aid in pressing the new bearing on. I ended up grinding off the cage of the OEM bearing and using it's inner race as a spacer.
Using the old race worked great and made it super easy to press the bearing onto the pinion. Again, in my case there are no depth shims that go behind the pinion bearing, so I won't need to remove and reinstall this one repeatedly.
I then put the pinion into the housing, slid the rear bearing and yoke on, and snugged down the nut. For setup purposes I'm not using the crush sleeve and am reusing the old nut; when I do the final setup I will use the new crush sleeve and nut.
To set pinion preload the nut is tightened until there is no longer any free-play and and there is also sufficient rotating torque on the pinion. To measure the preload I'm using a beam-style in/lbs torque wrench. The measurement you want is the torque while rotating the pinion, not the initial torque required to start it moving. During setup I've been shooting for about 20 in/lbs, spec being 15-35 in/lbs for new bearings.
Next I was ready to start setting up the carrier shims. I built my shim stacks for each side of the carrier based on the thickness of the OEM shims, though I did remove about .015" to remove some carrier preload to make setup easier. I will add back equal shims to each side during final setup to get more carrier preload.
It was now time to measure and fine tune my backlash for the first time. I setup my dial indicator and angled it so that the tip of it would be as close to a right angle as possible against the gear tooth. Then just held the ring gear steady, zeroed out the dial indicator, and measured the backlash. The backlash should be checked in a few places around the ring gear to ensure there are no issues.
The FSM calls for a backlash of .005"-.008". Shims are moved between the left and right sides of the carrier in order to get the backlash in spec. Add more to the ring gear side to increase backlash, remove some from ring gear side to decrease backlash.
It was at this point that I realized I had some major issues I needed to address. My initial attempt at checking backlash showed I had backlash around the ring gear of .002"-.009", way outside the spec, and way outside of acceptable run-out. No adjustment I could make to shims seemed to make it better. This is when I decided to consult with Rob. Initially he had me remove my ring gear from the carrier and measure the run-out on the carriers gear mounting face. It was within spec at .001" of run-out, so that ruled out the carrier being the cause. It was possible when I installed the ring gear that there was debris trapped under it (though I didn't see anything), so I reinstalled the ring gear and tried to make another backlash measurement. Still had the same amount of inconsistency as before.
The next thing we tried was to setup the OEM gears back into the housing and measure the backlash on them. I proceeded to do this, however, because I pulled off the old OEM pinion bearing and re-purposed it for a tool I needed to remove my new pinion bearing and install it onto the OEM pinion. I also reinstalled the OEM depth shim behind the pinion bearing and removed the shims from behind the bearing race; I wanted everything to be as close to the OEM setup as possible for this test. After installing the OEM gears back into the housing there was a similar amount of inconsistency on that set too. At this point it seemed like there could be an issue with my housing. However, because the new carrier only had .001" of run-out it seemed unlikely that the housing was at fault. The only thing I hadn't touched yet was the outer pinion race, so we decided I'd try reinstalling that as a last resort. I drove out the outer race, drove ensured everything was clean, and drove it back in ensuring it was straight and seated completely. After setting the OEM gears back up the backlash inconsistency was gone!
Next I got everything swapped back so I could setup the new gears and check the backlash. It turned out I still had some issues with backlash inconsistency on the new gears, but it was less than before. I removed the carrier and pinion gear again and made sure the bearing races were seated properly, when I noticed my problem staring me in the face. I ended up using the wrong shim behind the pinion race, and the top of the bearing cage was actually contacting it when everything was installed. I blame that one on the stress of the situation
. After I got my shims sorted out and I ensured that I was installing the right ones this time, I removed the inner race and reinstalled it with the correct shims, and then reinstalled the gears. Checked the backlash and was happy to see I finally had consistent readings with the new gears installed!! The lesson to be learned here is to make sure everything is super clean and straight when you install bearing races; and that just because a shim fits, doesn't mean it belongs there
.
Alright! Now that my gears were able to be setup properly, I continued. I adjusted my carrier shims until my backlash was within spec and then proceeded to paint a section of the ring gear to make a pattern check.
In order to get a good pattern the gears need to be loaded (have resistance put against them) as you rotate them. There are many ways to do it, I tried a few methods, but what worked the best for me was jamming some wooden wedges against the ring gear and housing.
Each time I did a pattern check I rotated the carrier two complete revolutions while it was loaded before I read the pattern.
My first setup was with .035" pinion depth, and .007" of backlash, the pattern showed the pinion needed to be deeper.
It took me 6 attempts until the right pinion depth was found; initially I added a large amount of shims until the pinion was too deep, then backed it off until the pattern started to look good. Each time I adjusted the depth I would need to bring the backlash back into spec by moving the carrier shims around. I ended up with .048" depth and .007"-.008" of backlash; the pattern looked good and had Robs approval:
That's where I left off for now. Next I will replace the axle bearings and seals, and drill a hole in the housing for the e-locker wiring, and then finally final setup.
