High Mileage Differential Fluid ???

[CharBaby]

My wife '01 RX-300 AWD has a mild leak in the rear differential on the driver side shaft seal of the Rear Diff.

I have been using Mobil 1 75W90 LS the past several D&F's on the TC and Rear Diff since we have owned the RX new!

It was only weeping mildly when I changed the Rear Diff & TC a couple of weeks ago and now has developed into a very, very slow drip(Read Diff-driver side seal only). I'm sure that the new M1 is doing some cleaning as well and maybe even contributing to the seal leaking more. The TC is fine...No leaks what so ever!

Since there is HM oils and HM ATFs that swell seals and such, is there a gear lube for my application that is considered a HM???
Or, should I wait and see if the leak(which now developed), slows down with the newely installed Mobil 1 75W90 LS???

Can I spray any brake cleaner or in that area to clean out the crud around the seal or is brake cleaner too strong???

Thanks,
CB

 

[Bgallagher]

None that I am aware of. I think you are going to have to fix it the old fashioned way (replacing it.)

I wouldn't recommend brake cleaner as it could cause further damage. If you can take it apart and wipe it down with rags you should be OK. Whenever I change diffs I drain and fill with cheap fluid (supertech) run it for a week or so then dump and fill with whatever good fluid I want. That does a good enough job flushing the crud out.

 

[Texan4Life]

no, but you could brew your own by adding some AT 205 reseal, which is straight seal conditioner. wouldn't hurt to try imo.

 

[SOHCman]

I believe that HM oils use Esters to swell seals, whereas the mobil one syn is mostly a PAO which shrinks seals.

You could try a Ester based syn gear oil like RedLine 75w-90, that might act like a high milage oil?

 

[MolaKule]

Quote:
I believe that HM oils use Esters to swell seals, whereas the mobil one syn is mostly a PAO which shrinks seals.



Mobil Gear Oils use PAO and esters to balance seal swell.

I am afraid there is no magical chemical fix except to replace the seal. It would be a good idea to have the shop replace the bearing as well.

 

[SOHCman]

Originally Posted By: MolaKule
Quote:
I believe that HM oils use Esters to swell seals, whereas the mobil one syn is mostly a PAO which shrinks seals.



Mobil Gear Oils use PAO and esters to balance seal swell.

I am afraid there is no magical chemical fix except to replace the seal. It would be a good idea to have the shop replace the bearing as well.


Correct, however Redline is primarily ester and M1 is primarily PAO. That is what I was getting at and why it might help. Obviously an oil will not "fix" a seal, but the abundance of esters may sufficiently swell the seal for the time being. Bottom line, its always better to simply replace a seal if you can afford downtime on the vehicle.

 

[JR]

i am with sohcman, if you have a minute in the scedule for downtime just tear it down and reseal the diff.

kc

 

[CharBaby]

Thanks for all of your input folks!

 

[dailydriver]

Originally Posted By: Texan4Life
no, but you could brew your own by adding some AT 205 reseal, which is straight seal conditioner. wouldn't hurt to try imo.


I was also thinking about the above, and maybe even some Bar's Leaks rear Main Seal repair, or Engine Oil Stop Leak, but even if they did work (and I take Mola's word/expertise on that they don't as GOSPEL!), they cannot be a good thing for the high-shear environs of a ring and pinion and l.s. or open diff!!

 

[gamefoo21]

I've had good luck adding an ounce per qt of the ATP Re-Seal 105(IIRC) to gear oil.

It's really helped clear up some weeping seals in various gear boxes and rear ends.

 

[CharBaby]

Originally Posted By: gamefoo21
I've had good luck adding an ounce per qt of the ATP Re-Seal 105(IIRC) to gear oil.

It's really helped clear up some weeping seals in various gear boxes and rear ends.


Thank you,

Right now, the leak/dripping has stopped! IDKY?
Yeah, it's still a bit wet around the seal and Diff Body but it's not dripping at all. I don't want to eat my words here!

I'm thinking that when I changed out the Diff Fluid with new Mobil 1 75W90, which BTW, is what I had also used on the previous change a couple of years ago, the the M1 cleaned the gunk from the seal and resealed/swelled the seal, causing and stopping the leak. Hmmmm!

Because the new M1 didn't start leaking til about a week later and then stopped another week afterward...Like I said; Hmmmm!

Same for the Transfer Case! It was alerady weeping even before I did the NEW M1 change and it has now stopped too...Hmmmm!

My way of thinking is...These units may both, start/stop weeping as the outside temps change and as the seasons change, IDK! I'll keep and eye on things