A riddle, what is this?

[Doktor-t]

The other day I took som photos of my cars undercarrige. Found som black crap on the rear section of the exhaust. It looks like some kind of oil or something but I´m not sure.

The strange thing is that the car doesn´t got any leaks, the garagefloor is clean and dry.

Be my guest, guess what you think is the most likely explanation.


Regards

Tobias

 

[Doktor-t]

riddle

Forgot the photo

 

[speedmaster4]

hard to tell from pic but color and location are typical rear axle seal weepage...no big deal, just make sure the differential doesn't run dry...don't bother fixing it, it will probably just start leaking again in a month....if you occasionally notice an unusual smell like somebody is cooking something when you first stop the car--its you frying a little rear axle grease...smile-at least that part won't rust

 

[Doktor-t]

rear axel

Okey, that´s not a serious thing then. Good to hear.

What kind of fluid is to be used in the rear axel?

Is it reasonable to expect some improvment by pouring in some gasketconditioner?


Tobias

 

[speedmaster4]

many lubricant vendors sell high viscosity oils made for rear end gear use--should say so on the bottle--look for ''limited slip'' recommened...you can improve operation and reduce noise from the rear end by adding small bottle of ''positraction axle additive'' available from any gm dealer...two bottles of this added to the front gearcase of MANUAL transmissions improves shifting also.

the factory doesn't put this additive in because its an extra cost that most buyers won't miss and its also ''sperm whale oil''--superior lubricant but the tree-grabbers would freak out

most ''seal conditioners'' only break down the rubber of the seal to improve the sealing temporarily--it leaks worse later

btw--not the best lube but best smell when it burns off-castrol

 

[Doktor-t]

rear axel

Okey, it seems best just to maintain fluid levels. That´s not to hard

 

[Doktor-t]

rear axel

Went under the car today and determined that the diff is leaking oil. The oil seems to leak at the gasket that seals towards the driveshaft.

The fluid level was okey and that seems to be most important. It smells kinda funny after some hard accelerations.

I think I will fix this when I build a new exhaust since it seems necessary to remove that anyway when changing the gasket.

Tobias

 

[speedmaster4]

remove the nut from the pinion shaft to pull the yoke (it is tightened to 200 ft/lb).. a small gear puller will probably be reqd to pull the yoke(carefully tapping with a hammer may work but its easy to damage) ..polish the yoke at the point of seal contact--that is probably corroded and is the reason its leaking now--replacement of the yoke is NOT necessary unless it is very severe corroded or grooved...apply axle grease grease liberally to the lip of the new seal and to the yoke at the seal contact point...the pinion nut should be torqued to 200 ft/lb plus or minus 10 ft/lb,use blue loctite when installing the nut and apply several drops to pinion shaft/nut juncture after torquing to seal against water infiltration.

or just look at it like a cute little puppy that isn't quite housebroken...the vettes that dont leak at the rear end seal are unusual

 

[Doktor-t]

rear axel

I will fix it this summer because it´s annoying with leaks. It´s way to cold in my garage right now to get down on the floor, probably it would only make my cold even worse Manana manana

 

[wro87]

leaking rear end

Hey just another comment! We have an 87' with 32K miles and the same thing is going on. If you get to a shop that could put it on a lift it seems to be the front seal. I aggree it is not worth the trouble to put a new seal in and if the shop that does the oil changes is real good they will be looking into the level in the rear end and keeping it topped up. Good luck! WRO

 

[Doktor-t]

Rear axel

I don´t really get it, why shouldn´t I bother changeing the gasket? I mean, it´s kind of a neglect not to. In my opinion that is.

Anyway, the plug that i screwed into the sight/fillinghole gave me some pain in the ass though. Even though I gave the threads a going over with a wirebrush it was indeed challengeing to get it back into the diffhousing.

Even though I used a extension on my allenwrench it didn´t dear to screw it all the way. It seems like the threads had other ideas. Since it is conically threads the should be a bit tough to screw in but this was a bit too much I think. A applied some threadsealer to the threads just to be sure.

Are there any ventilationgadgets on the diff maybe? There are ventilation on camaro/firebody diffs.

 

[davec0_17]

leak

I'm with you, doctor-t, I would change the gasket. I hate leaks, smelling and smokin, leaking on my floor. Your going to be close with the exhast off. 200 ft lbs thought, you will need a big pipe to break that mother loose. They are easy to come by. You do enough work on cars, you will have one laying around I'm sure.

 

[Doktor-t]

rear axel

Yea I read about that torque spec in the Haynes manual. Even though it might be a challange I think I can manage.

 

[davec0_17]

Yea, the axle nut is what, 160 ft lbs. Its not that much more.