DIY Gear Swap - Step by Step Pic's - Rubicon 4.88

fixbroke

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Ok, finished up my install today. This CA coronavirus isolation order came in handy, but it can be over now!

This took way more time and effort than anticipated. I think I re-shimmed the rear end around 8 times and the front around 3 times. I spent the better part of 4 days doing this, though the frustration of re-shimming a jillion times definitely ended some of those days early.

Notes:
  • Installing a new pinion crush sleeve doesn't require that the pinion seal and nose bearing be removed.
  • This is a pretty good guide for reading gear paint patterns: http://departments.weber.edu/automotive/YouTube/Weber_Ring_Gear_Contact_Pattern_Interpretation.pdf
  • A slide hammer works better than a punch and hammer for removing the pinion tail bearing. It also works well for removing the carrier from the housing, especially if you haven't installed all your ring gear bolts yet.
  • Don't remove the parking brake cables. I don't think it's necessary, and if you're unlucky as I was then one of the cables will drop out of the cabin lever and you'll spend some time disassembling your front console to access the underside of the parking brake lever.
  • Before you decide that your pinion depth is good, ensure you haven't left any axial play in the pinion. You don't need to have your crush sleeve crushed to spec, but you shouldn't be able to feel any play at all when pushing/pulling on the pinion.
  • Similarly, make sure that your backlash is in the ballpark before you decide your pinion depth is good. I found that backlash really changed my gear paint patterns and was heartbroken when I figured out that I'd need to keep shimming that damn pinion after I thought I had done it for the last time.
  • If, like me, you find yourself unsure how much shim to add/remove, use 0.010"/0.25mm increments. That seems to be a good number for moving the gear pattern around 20% of the way across the gear tooth.
  • Installing thin carrier shims is a pain. Try to use the thickest shims possible as opposed to stacking up multiple thin shims.
  • Don't trust the Dana etch numbers. The following is where I ended up for shims, which doesn't match at all what is expected from the etch numbers.
FRONT
Stock pinion etch: 0.56
4.88 pinion etch: 0.69
Stock pinion shim: 1.08mm
Theoretical new pinion shim (based on etch difference and stock shim): 0.95mm
Actual pinion shim for good paint pattern: 1.18mm
Carrier shims: no change from stock (backlash a bit tight, but acceptable)

REAR
Stock pinion etch: 0.55
4.88 pinion etch: 0.18
Stock pinion shim: 1.18mm
Theoretical new pinion shim: 1.55mm
Actual pinion shim for good paint pattern: 1.03mm
Carrier shims: +0.25mm farther from pinion





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Portmod7

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Ok, finished up my install today. This CA coronavirus isolation order came in handy, but it can be over now!

This took way more time and effort than anticipated. I think I re-shimmed the rear end around 8 times and the front around 3 times. I spent the better part of 4 days doing this, though the frustration of re-shimming a jillion times definitely ended some of those days early.

Notes:
  • Installing a new pinion crush sleeve doesn't require that the pinion seal and nose bearing be removed.
Sounds like you had about the same experience I did. The rear in my Jeep was a circus.

I don't know what I was thinking on the crush sleeve, it definitely comes out with the pinion, not out the front.

Hope you enjoy the gears, I'm enjoying mine!
 

fixbroke

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The 4.88s are great, especially for the M6. I was really getting tired of having to downshift to 4th for the slightest of hills on the highway.

A couple more notes:
  • My Tazer JL was failing at setting the new ratio until I reset all the onboard electronics with a full battery disconnect. If anyone has issues with Tazer gearing changes, disconnect both batteries and try again
  • It looks like all of those pinion changes in the rear end have ruined my pinion seal, so I'll be replacing that one anyway. Grrr. There's a fine splatter of oil on everything behind the pinion. No dripping, though.
 

19JL

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So I have A question, what happens if you didn’t Mark the actuator plate?
 

19JL

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According to Dana, and what we had to do on my Jeep, you have to keep clocking it until you lose the blinking locker light (By getting it in the right spot)
So is there no way to tell exactly where it needs to go? That requires pulling off the bearing each time. :(
 

fixbroke

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So is there no way to tell exactly where it needs to go? That requires pulling off the bearing each time. :(
Maybe you could plug in and actuate the locker without installing the bearing to see if the locker light blinks or not. Try it in a few different positions without actually installing the carrier to see if some positions work and some don't.
 

MadDog27

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I ordered a set of gears finally. Going to go to 4.56s as I’m at 34s for tires and plan to only go as big as 35s.

What diff fluid weight did you all use after you installed the gears? What about after the 500 mile break in?

Wish me luck!

Edit:
@chevymitchell responded already. Looks like the tow weight is used during break-in.
 
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MadDog27

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Wonder if you all can help me out. I haven’t started tearing into mine yet, probably won’t start for a bit. Just gathering parts and tools right now.

Anyway, the gear set showed up today. The pinion for the Dana 44( M220) has +02 etched on it. So I’m assuming that means 0.2mm correct?

The Dana 30 pinion (M186) didn’t have anything etched on the shaft itself but it did have a Q 0 15 on the head of the pinion. Pic below. Does that mean 0.15mm?

B41BA077-5D9C-402A-8E66-B862CC8FA21B.jpeg


DF62CF23-D7DF-4EFE-967B-6A5754131D1E.jpeg
 

MadDog27

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I was inventorying my install kits for the regear. I noticed the Dana 44 (220) kit for the rear was missing carrier shims for the smaller bearing. I called East Coast supply and they said you only shim one side in these new Dana 44s. Is that right?

If that is the case, how are you able to keep the preload the same if you have to add or remove shims to get the backlash within spec? When you guys did yours, did you only shim the bigger side for backlash? Any issues with the carrier bear preload when removing or adding carrier shims?
 

islandtees

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You have shims on both sides of the carrier. You should have small and large shims in the kit. I did.
 

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