Overfilling the differential

[JHZR2]

Hi,

Are there any issues with overfilling the differential of a car? When I opened the fill plug on mine, a LOT of fluid gushed out. The diff was warm, but not hot to the touch.

Will overfilled diffs cause extra noise?

Thanks,

JMH

 

[srivett]

Is that a rear axle diff? A seperate but joined transaxle diff can fill with the fluid in the gearbox.

I had a boss that used to overfill heavyduty equipment diffs by putting a rag over the hole while filling it. Then he'd quickly put in the plug. It's probably not good for mileage but he was quite smart.

Steve

 

[mechtech]

Rear differential units generally have a lot of air space, and a vent.
A little overfilling won't make a harmful difference.
The fluid and gears expand quite a lot when even moderately warm.

 

[JAYCEE]

I overfill mine just a tad by parking the vehicle a few inches up on ramps when filling. I fill just enough for it to run out when the check plug is removed on level ground.

No problems here.

 

[MolaKule]

I also use JAYCEE's method. Overfilling will cause extra foaming to occur. Let the excess run out on level ground.