74 GTV Leaking Differential

[zoom]

"Dino" (dead dinosaurs) is slang for lubricants derived from conventional stocks versus synthetics.

80/90 is good.

BTW let us know if this takes care of your "bump".

[lowmileage]

Syn gear lube and motor oils are "more watery" in consistancy than "regular" Dino gear lubes and motor oils. Syn's are like anti freeze in that they tend to find their way out of a motor quite easily IMO.

[Andrew]

Thicker oil is no guarantee it won't leak, but it might slow down. "Dino" means standard mineral oil (from decomposed, compressed dinosaurs), not synthetic oil.

Andrew

[lowmileage]

Quote:

Originally Posted by Andrew Thicker oil is no guarantee it won't leak,

[MidLifeCrisis]

I just replaced my pinion seal if you're interested in seeing what a leaking one looks like. This is after some cleaning and you can still see the staining from the chronic leak. The special socket to get the nut off cost me about $65 at IAP.

[Steve Semeraro]

So far, so good. Sort of. I replaced the differential oil with 80w-90 gear oil and drove the car a short distance. The good news is that there appear to be no leaks (12 hours later) and the slight rumble at the rear wheels, which I had called a bump, when taking off from a dead stop seems to be gone.

The bad news is that now there is a much louder clanging sort of noice coming from what seems to be the right rear of the car when I upshift. Arrrg. It seems transmission related, but is not consistent in volume or apparent location with every shift. I will have to drive the car a little more to get a better feel for it.

FWIW, I have had the car for about a month. It was completely checked out before I bought it. No problems, and was fine for me until about a week ago.

[Andrew]

Sounds like it's time to involve a shop or knowledgeable Alfa friend. Get it up in the air and get under there and poke around, seeing what's loose or not right.

Andrew

[Steve Semeraro]

Andrew's right, and I will take his advice. But "House" viewer that I am, I can't help trying to diagnose the problem. If others are interested in speculating, here's the latest. Took the car out this morning and drove it to work, about 10 miles. No problems at all. No leaking at the differential. No clanging noises. Devine intervention, perhaps. But a possible explanation is that the noises I heard yesterday afternoon were heat related. The car had been parked out in the sun for several hours and it was hot outside. This morning, it was sitting in a cool garage, and the outside temperature was quite cool. I'll find out soon enough when I take the car to Foreign Auto Menders, the long time Alfa specialist in San Diego. But if others would like to speculate, I'd be interested in your thoughts.

[Andrew]

Depending on where you are in San Diego, Mike Mulligan took over Fred Zimmerman's old shop in Vista. I met Mike at an AROSC time trial school, and he knows his stuff, though he's a racing and Porsche guy who is picking up Alfa experience quickly. Very nice guy to deal with.

I'll be curious what you find.

Andrew

[Roadtrip]

On the differential "bump", check the condition of the rear transmission mount, u-joints, guibos and center driveshaft support bearing.

On the clanging, check the exhaust hanger mounts. Also the center muffler has a common fault of having an internal baffle come lose and cause noise at odd times.