Rear Diff Service and Determining Gear Ratio

[flick2614]

I'm pulling my rear diff cover this weekend to clean up the diff and swap fluid. What's the best practice here; drain, wipe down spray with brake cleaner, repeat wipe?

Also I bought this Jeep lifted on 37's (2021 Rubicon Diesel) so I really don't know if it's been re-geared. Is there a way to count the teeth to determine the ratio?

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[beast40]

Jack it up. Mark your Drive shaft with paint or marker. Spin the tire a full rotation and count how many times the driveshaft turns.

 

[kah.mun.rah]

this

 

[CarbonSteel]

I would wipe it down with lint free towels like Scott's. I would not spray any solvents into the housing.

 

[Ratbert]

If you're going to open it, then count the teeth on the ring gear and pinion gear. Divide ring by pinion. E.g. 41 ring / 11 pinion = 3.73.

 

[lashlee]

Pinion may be hard to see. I would do the tire/driveshaft calculation.

 

[Grayhound]

I would look at the menus of either the tazer or jscan to see if it will tell you.

I'm 99% you're going to find the 3:73s

 

[jadmt]

pretty to get ballpark but using this calculator. take your actual tire measurement not advertised size and see what your rpms are at 60 or 70 mph in 8th (0.67) or 7th (.84) or 6th (1.0) if you use 3.73 and that is what you have the rpms should match the calculator
https://purperformance.com/p-29669-rpm-calculator.html

 

[Ratbert]

I would look at the menus of either the tazer or jscan to see if it will tell you.

That makes an assumption that the speedo is somewhat accurate.

 

[Lofty]

Ring gear should have the ring and pinion tooth count etched into the OD. clean with a rag and you should be able to see it

 

[flick2614]

That makes an assumption that the speedo is somewhat accurate.

Speedo is def not accurate

 

[flick2614]

Ring gear should have the ring and pinion tooth count etched into the OD. clean with a rag and you should be able to see it

Stupid question: what does OD stand for?

 

[Ratbert]

Speedo is def not accurate

Then you'll want to get a Tazer or Jscan. After determining your gear ratios, of course.

 

[Vinman]

Stupid question: what does OD stand for?

Outside diameter of the ring gear will have the gear ratio etched into it

Heres a random example I found, 11 and 41 indicates 11 teeth on the pinion and 41 on the ring gear. 41 divided by 11 equals 3.73 ratio

 

[WannFly]

pot those lockers while at it


https://www.jlwranglerforums.com/fo...ion-sensor-potting-dana-44.59581/post-2866834

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