bad axle seal or synthetic oil?

ok, so about a year ago I had a rear axle seal go bad, i got my mechanic to replace it, then a couple months ago I did a rear diff fluid change, now, i recently saw some fluid coming from the rear axle seal again, it sprayed up all over the inside of my fender well. so I'm wondering if it's the synthetic fluid.. or the axle seal again? It's gotten low so my plan is to fill it with regular diff oil and ditch the synthetic for now. whatchya think?

 

as long as you drain all the synthetic then you should be fine, dont mix synthetic and regular oils though..

 

gotchya! damn I wish I was home, with tools..

 

Sounds like the seal again. Synthetic oil causing a seal to go bad is now known to be a myth, or so I have been told by many.

Sounds like he installed it wrong or a bad seal?
I think staying with synthetic is better, but you can go with dino, it will be OK.

 

alright, I'll refill with synthetic until I can get home and fix it. sucks to pay for it twice in a year

 

after i got it fixed i would go back to synthetic, im runnin royal purple gear oil in my diff's

 

Yeah man that sucks! I recently noticed some oil residue on the bottom of my diff. So I torqued all the nuts to factory specs, and all of them were lose, by a lot.

After cleaning off the bottom and putting synthetic oil in, I haven't noticed any more oil residue.

 

I can assure you it is the seals, and not the oil. Contrary to popular belief, synthetic oils do not cause oil leaks, rather bad seals cause oil leaks. Toyota doesn't make the best axle seals so it wouldn't surprise me one bit that the seal is leaking, but if your mechanic did not install the seals properly they will also leak and fail prematurely.

You can mix synthetic and dino oils all day without and ill effects too.

 

weird, but I'll figure it out. I'm glad it's not cause of the synthetic. new seal and a breather extension when the holidays are over

 

Your breather isn't clogged, is it? Thats another thing that will cause the seals to fail.

 

it shouldn't be, but I'll have a look tomorrow before my trip.

 

ive always heard that mixing weights was ok but not synthetics and regular oils. but i may be wrong..

 

better safe than sorry, I'll stick with what's in there, and replace when I get a new seal.

 

Nope, it wont hurt a thing. Now I wouldn't go out of your way to do it because its pointless, but a mix wont hurt anything. After all, most all 'synthetics' are actually blends of dino and synthetic base stock.

 

wow i learned sometin new today ha ha

 

maybe, sc4333, not to be rude, but how do you know it won't hurt? any explanation of why or why not?

 

To put everything into the simplest terms oil is categorized and rated by different standards. Mixing oils, regardless of synthetic or dino, in the same standards will have no ill effects. Mixing oils with different ratings is still possible and can almost always be done without encountering any problems. The place an issue could potentially arise when mixing outside of a compatible rating is with additive packs and don't jive well with each other.


For instance, what goes into my taco is Mobil1 5w-20. It is a ILSAC GF-4 API SM, SL/CF oil. Technically I can take it and mix it with any SM, SL or CF oil with complete compatibility, synthetic or not.


If you want to learn more about oils, check out bobistheoilguy.com. It is a really informative site, with all kinds information on oil. Most likely more than you would ever want to know.

 

great! thanks for the info!

 

also check the rear diff breather. If its stuck shut the pressure build up in the rear diff will push out the seals...

 

yea thats what they said on ttora too, thanks for your help. I'll check in the morning