Transmission Re- Gear rubi 4.88

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Gordon
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Hi Guys, looking for some information regarding Re-gearing to 4.88 on my JL Rubi, Once new gears have been added what temp should they not exceed, while running them in Ie dont want to cook them.
I know all about the first 500 miles ie slow and run for a few hours and stop 30 mins or so until the bed in, but i wanted to get a handle on temps at the start, any ideas?





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D60

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Differentials, not transmission

You're NEVER gonna get a handle on temp of the ring & pinion or even the gear oil w an IR therm.

You'd have to pull the diff cover quickly, dump all the gear oil and shoot the ring gear

Just drive it easy and don't tow for the first couple hundred miles.
 

WXman

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This isn't magic. There are a few instances of factory diff. temp readouts on vehicles. You probe the fluid just like you do for the transmission. You make your judgement calls based on fluid temps, not part temps.

I think his question is what would a safe and normal temp be for diff. fluid at operating temp? Very fair question.

I have never probed my diffs and measured them, but from what I've read you should expect somewhere around 200°F at max operating temperature.
 

D60

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Sure, you can even install aftermarket gear oil temp gauges

Go for it!

It's only money honey

The Pricing forum is full of people who flew several states over and then drove a brand new JL several states back home.

I've always wondered about alleged break-in on new vehicles with gears, brakes etc 'cause it doesn't happen. I hopped in my Rubi with 10 miles on the odo and drove 1.5 hours home (shrug)

Even so, the temp of 80W-90 isn't an accurate representation of the temp of the R&P
 

mwilk012

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This isn't magic. There are a few instances of factory diff. temp readouts on vehicles. You probe the fluid just like you do for the transmission. You make your judgement calls based on fluid temps, not part temps.

I think his question is what would a safe and normal temp be for diff. fluid at operating temp? Very fair question.

I have never probed my diffs and measured them, but from what I've read you should expect somewhere around 200°F at max operating temperature.
It reads like OP thinks the differential that is being regeared and the transmission are the same thing.
 

LunchBoxFab

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Even so, the temp of 80W-90 isn't an accurate representation of the temp of the R&P
Granted, the oil wont be the exact same temp as the gears, but if the oil is cool or cold, there is no way those gears are hot. the opposite should hold true.

that is useful info if you are breaking in a new set of gears.
 

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