Pinion Seal Replacement, Differential Preload, Oil Temperature, Etc.

[ERUSH97XLT]

I'm curious if anyone has any insight on normal differential operating temperatures for a stock 8.8 with 4.10 gears.

I replaced my rear pinion seal and U-joints this weekend and took care to ensure everything was exactly reassembled, including indexing everything. I did not check the pinion bearing preload as I don't own a beam style in-lb torque wrench. It is well documented that indexing the nut to the pinion and counting threads is a suitable preload workaround. It took tremendous torque to tighten the pinion flange nut to correct position - maxed out my impact wrench - but everything should be in the correct position.

I filled the differential with 3 quarts of Motorcraft 80W-90.

After a few highway test drives, everything seems to drive ok; no noises, vibrations, hums, etc.

I measured the differential housing temperature near the pinion area with an infrared thermometer to see if anything is overheating. I'm consistently getting 200-205 deg F after normal 70mph highway driving with ambient temperatures in the 60s. The differential cover is measured to be in the 160-180 deg F. range.

Are these temperatures normal? I've read elsewhere that the differential operating temperature range shouldn't exceed 200 deg F. Can anyone confirm or share their experience? I don't want to ruin any bearings.

thanks

 

[ERUSH97XLT]

Wanted to post an update. I've been measuring temperatures since my last post and they seem to be settling in the 160-180 degree range, depending on driving type and ambient temperature. I still don't have any hums, leaks, or whine so I think all is well.

Perhaps the brief increase in temperature was due to the bearings reseating a little after the work since I removed the outer pinion bearing for inspection when I removed the bad seal.

I'll keep this post updated if anything drastic happens.

Thanks for reading.

Eric

 

[Mbrooks420]

Should probably be running 75w140 full synthetic in the rear.

 

[ERUSH97XLT]

Thanks. Ford spec for my rear end is 80w90. I don't have the FX4 II package, so I don't need 75w140. Also don't need the XL-3 friction modifier as I don't have limited slip.

If I had some noise, I'd consider using 75w140 as Ford recommends it in some TSBs applicable to other vehicles addressing noise with the same 8.8 rear end.

 

[Mbrooks420]

It’s all the same axle, so I’d use whatever was in the TSBs. There was also no mention of what this axle was in, so I was assuming it was a Second Gen.

 

[ERUSH97XLT]

Apologies, my 2006 XLT Ranger 4x4. 8.8 Rear end, 4.10 gears.