Thread: RRC diff bearings-servicable???

Ah, the plot thickens.
I had a thought this morning that the Quaife diff centre may have been metric and the RTC 2726 carrier bearings may be wrong.
I was correct for the wrong reasons.

The diff is pre 85 or whatever and is not what is generally called imperial as it has a bigger OD at 3 inches or 76.2 MM than the later imperials which have apparently have an OD of 73.43MM. RTC 2726 cross reference to LM501349/LM 501210.
The metric 24spline bearing RTC 3095 has an OD of 73.5MM and an ID of 1.781inches or around 45MM.
Timken LM 102949/LM 102910

I have physically looked at the race and it is 3inches and is a Timken 26823 with 3.00 inch OD and I have measured the ID at 1.625. The Timken catalogue gives the bearing as 26882. As they are hard to remove I have not physically confirmed it. Or I could get RTC2726 and buy sleeves from KAM to increase the OD to 3 inches.

So it looks like the bearing is a hybrid of an early imperial 3 inch OD and a metric 1.625 inch ID and the Timken numbers above are the only ones that fit.
From my reading this situation applies to KAM and Detroit Locker( I know this one as this happened to me), and you have to buy a sleeve to increase the OD to 3 inches if you want to put a 24 spline locker in the old 80s diff as the 3inch OD Timkens do not come with a bearing with ID bigger than 1.625.
So there. This has driven me nearly mad today.
Regards Philip A

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Originally Posted by PhilipA

That contact patch you see is down a bit on what it was, about 1/16 a turn both sides on the carrier nuts. I have all the marks for the original position on the nuts, but I would expect these to change with new bearings.
Regards Philip A

yes, if there is a contact patch or contact wear on the gear then you need to set it up the same.. I'm tipping that on the side you're aiming to set up on that there will be a set of contact marks. Assuming there isnt the best you can do is set the diff up using the contact marks from the other side as your guide and setting the diff up to match them.

you'll probably find that setting the bearings one notch closer to the pinion will just about sort the patch that youve got, if it beds in too deep you may be able to finesse it out by redoing the pinion position or make the choice as to if you want too high or too low a contact patch, I tend to opt for a too low position if I have to.

I was / am in the same position.


Fitted an Ashcroft locker, brought the new pinion bearings, checked they were the correct numbers etc, and they were.


Knocked the old ones out, dropped the new ones in, same numbers all around, I presumed no reason to check the pinion height, as the same gear set was used, same model / spec of bearings

Gear set has done around 225,000km's no signs of damage in good shape.

Matched the pinion to the bevel gear, no issues, counted the turns on the bearing nuts 5 each side.


My mistake was I never blued the gears before I stripped them down.



Spent a half a day getting the contact good, but they never went back equal, i.e. 5 either side.


Down side is I have a whinnying diff between 110 through 125 km/h, wasn’t there before, when you back off the power you can hear it to.
Upshot is I will be taking the diff out again for an inspection to reset the bearings caps to as they were, hopefully it will cut the noise down, and recheck the back lash & blue contact.


Am I correct if the back lash / loose contact is out it can lend to noisy diff?