Differential vent ?

[Bluemill]

Is it possible that my very expensive, under estimated by 100% diff (left) seal job isn't leaking, and it's just some heated up gear oil gushing out the top? How do I check this? Is there a tube coming off this vent, or is it just a bit of a one way nipple valve or something like that? Where is it?

Thanks for your help as always!

Bluemill

[aquaholic]

don't know what year your car is but if it's a c5 there is a vent on top of it. do a search on here for it. there were some other posts dealing with that issue. one of them probably has a picture of it in the post. there are issues with filling the diff when it's not completely hot that will cause an overfill situation.

[Bluemill]

Dear Aqua,

I did as you suggested and found quite a lot of stuff on the subject. I like the idea of putting an "over flow" hose I guess over the base of the vent that would seal in the oil as it escaped, but at the same time not impair the vent "can" from going up to allow the oil pressure to release. Does any body know how big a hose to use?

I'm pretty thrilled that it's not a dealer bad service issue. There was a lot of oily mess at the top of the diff, right around that little vent can. This is great news, now I know it's a hot oil issue. I would think that eventually it would stop gushing over regardless of how hot, just because its out of the car, and it's not going back in on its own.

Bluemill
This is on a 2000 C5 6 speed coupe
dancefool-

[c4c5specialist]

HI there,
The differential fluid leve should be checked after 1/2 hour of run time, NOT COLD>
If you fill to the top of the fill plug, you will get oil out of the vent tube.
You should NOT have to add any hose, or anything else.
Simply check fluid level HOT and you should be fine.
Allthebest, c4c5

[Bluemill]

Now the other issue with the shade tree mechanic is that when we check the fluid level, it's usually with just the rear axle jacked up, because it's so easy to do the floor jack back there. Of course, that way you could overfill it by mistake, with that tipped thing going on.

So I have to see if I can drive it up on my all -4 wheels wooden blocks and see if I can squeeze under to check it out. My memory is that it's not too hard to get at. The hot aspect is something the tech at the Chevy garage did not factor in. Better too much than too little!!

Thanks Again, and congratulations on your recent well deserved award.

Vettes RULE!

Bluemill

[aquaholic]

pull the front of the car up onto a set of car ramps (i use the low profile rhino ramps) then, jack the rear of the car up until it's level with the front. works like a charm.

[1999 White C5 Coupe]

Originally Posted by c4c5specialist

HI there,
The differential fluid leve should be checked after 1/2 hour of run time, NOT COLD>
If you fill to the top of the fill plug, you will get oil out of the vent tube.
You should NOT have to add any hose, or anything else.
Simply check fluid level HOT and you should be fine.
Allthebest, c4c5

c4c5,

I am planning on changing the rear lube on my 1999 C5 coupe. I purchased the fluid + additive from my GM dealer.

If I put in the 4 oz. of friction modifier and 1.69 (1.7) quarts of fluid, is there any reason to later check the fluid when it is hot?

Thank you.

[c4c5specialist]

HI there,
The fluid capacities are always approxiamate.
Yes, still confirm the level afterwards.
Allthebest, c4c5

[1999 White C5 Coupe]

Originally Posted by c4c5specialist

HI there,
The fluid capacities are always approxiamate.
Yes, still confirm the level afterwards.
Allthebest, c4c5

Thank you.