So after some math, I made some shim adjustments. First try, I moved the carrier over to the pass side .010 and I believe I moved the pinion away from the carrier .005.
.004, too tight. Phooey
More math and playing with shim packs
Finally got it in spec, .007. Spec is .006-.010
Run another pattern, not bad, I think we're gonna try it
Borrowed a coworker's split beam torque wrench to properly check drag on the pinion. Still odd has marks but much better than my 0-800in lbs one. Didn't get any pictures but I took a big chance and did the crush sleeve with an impact. Spec on the drag is 14-19in lbs and you add a couple for the pinion seal. I nailed it right at 20in lbs. Score
So then I go to pull out the cross pin so I can install the axles...can't get it out. I'd read about this years ago but forgotten that for most gearsets 4.88-up, you have to grind down a tooth to clear the pin. Didn't feel like doing that this day so I moved onto the front axle. Needed a change of pace.
Did I mention this thing lived on dirt roads and had an oil leak? lol
First thing was getting the sway bar and center link/TRE's out of the way
This is my first time dropping a front diff and other than getting the center link free of the idler/pitman arms, it's super easy. I'll never attempt an oil pan reseal in a 4wd without pulling the diff down
The engine leaks from every orifice just about
Started disassembly by removing the pass side/long side extension housing
This is looking at the pass side extension housing, this is what the front axle actuator does. Just slides a shift fork and gear over the stub shaft to engage everything
The inside looked pretty clean, the gear, the carrier and the spiders all looked good
Carefully split the case, gotta go slow cuz it's aluminum
The bearings are a little chewed up and dark, I think they got hot
There's a light blue hue to the races too, these things got hot. I'm assuming he probably forgot it was in 4wd (probably more than once) and ran it like that for a while. Or low on fluid, or both. Even though the fluid I drained out looked good, it'd probably been changed
I'm tell ya, if you think you'll ever do axle work, buy this bearing puller. It is an absolute godsend. Although I was informed after this that I should be using the race to help further support the bearing. Not a big deal for bearings you're not gonna reuse but definitely important if you are
Threw the pinion in with the setup bearings (same ones from the rear end) and no crush sleeve or seal, adjusters back in, new races and ready to put the halves back together for a test fit
Remember, I'd left the adjusters in the factory positions. That wouldn't even allow the case halves to sit down together. I played with it a few times and finally just said fuck it and ran the driver's side one all the way out. Finally the case halves would seat
Then I started sneaking up on the passenger side adjuster till it had some tension. Unfortunately that special spanner tool I had is the wrong one, it's wayyy too big to even fit down in this section of the case and the pins are too far apart, they wouldn't even work in the adjusters anyway
So once it seemed to spin pretty well, I rigged it up to measure backlash
Big ole honkin' Dodge Durango battery works great for holding the case still
So spec here is the same as the rear, .006-.010. Since you're measuring at the yoke and not on the ring gear, you have to divide by 2. This is extremely hard to do and it takes a while to get the "feel" to know you're in the right range. And each reading came out a point or two different, so I was just shooting for a good range. I fiddled with this for probably an hour before I felt comfortable with my results. Ended up getting .016-.019 consistently, which puts me at .008-.0095, perfect. Time to paint.
Not a bad pattern. I'm still playing with my paint+gear oil mixture but this isn't bad. And for a front diff that only occasionally gets used, I decided to call that good and run it.
I heated the final assembly bearing up in the toaster oven at 250* for ~30min while the pinion was in the freezer and I ate dinner. Plopped right on.
So then it was time to put the pinion in with the crush sleeve and pinion seal. This SUCKED ASS. I didn't wanna risk this one with the impact so I used my coworker's pinion holder and a breaker bar. I started with my 1/2" breaker and it didn't take long before it started to spread the ears on that one. I got frustrated and grabbed the impact, thankfully I remembered that the boss has a 3/4" set so I grabbed that breaker bar and a jack handle. That worked really well.
But I was sneaking up like 1/4" of rotation at a time for nearly 1.5hrs before I finally got the drag in spec. These are a little different than the rear axle, the rear axle you can tighten the nut down until you have the front to back "slop" out of the pinion and then worry about crushing the sleeve. But the front axle, you start getting into the crush sleeve long before you're out of "slop" in the pinion. Not fun.
When I got done I just laid on the floor for a few minutes, that was a MF'r lol
Then back on the bench to double check that I'd see the drag correctly, it was hard to judge on the floor. I did thankfully
Also tried to buy new straps/hardware cuz I had 1 bolt head start to round off on me. WTF is this shit!? So I was just careful with everything going back in.
So once all that was done and I ate lunch and ran a couple errands to let the gasket maker setup up, I decided to run it on the lift. It all sounded ok like that but I wasn't running it fast and wasn't about to get out with the wheels turning since I was by myself. But 2wd and 4wd both sounded fine, so down and on the ground for a test drive.
Got ~50yds out the door and start hearing a faint rotational sound. Almost like I can hear the teeth meshing in the rear end. Doesn't sound bad, just a sound. Almost sounds like I have too much backlash or the pinion moved on me.
So then I go around our building into the dirt on the backside to test 4wd and make sure it doesn't bind up. Seems good in 4lo. So put it back in 2wd and get back on the pavement for a long straight run. Put it in 4hi and over 10-15mph I have a terrible bearing roar. Dammit.
So both axles need to come back apart. Phuck my life.
So a month went by of fighting these gears off and on. Ran god knows how many setups I ran and I actually assembled and drove the truck on 2 more setups that were also noisy as hell. After talking with several other people, we came to the conclusion it was the cheap ass USA Standard gearset I bought. So I ordered some from Revolution Gear after reading lots of good reviews. They're machined wayyyy better, are 2-cut vs the other 5-cuts (OEMs use 2-cut cuz they run quieter) and the patterns read so much easier.
Cleaned out the housing real good again and threw the first setup in last Friday. Here's a comparo of the old gears (left) and the new gears (right). That's the first setup with the new gears using the factory .036 shim. Pretty good right off the bat but I wanted to cover my bases.
Ended up running everything from a .015 to a .042 shim just to see how these would react. It was very easy to see what they were doing with each change
Had one little hiccup Tuesday when I tried to throw in the final .038 setup we landed on (with advice from a couple buddies that do gears and also Revolution directly, awesome customer service BTW), I had heated the pinion bearing in a toaster oven and threw the pinion in the freezer but it didn't seat all the way. Pulled it back apart yesterday, threw it in the press and got the pinion seated all the way. Ended up with a .005-.007 backlash and a good pattern
Threw the driveshaft, axle shafts in, filled it with fluid and drove it at lunch today. Put 10 miles on it and it's SILENT!! Success!!
So now I have to tackle the front diff. I've converted it to 2WD for now by taking the CV's apart and throwing the stub shafts back in the wheel bearings and removing the front driveshaft, that way I can work on the front diff on the bench at my leisure.
Got almost 350mi on it now, still silent. I'm still driving it easy till I hit the 500mi mark and do a fluid change but 4.56s and 32s is alot of fun lol
