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65 Riviera rear end seal leaking even after seal replacement..!!


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Hmmm,

I have had a very slow leak out of the rear end seal ever since I have owned my 65 Riviera, and I decided to have the rear seal replaced a while back. It started leaking again shortly after that, so I made them replace it again, now it has started leaking gear oil again??

I'm not sure what to do. The gear oil may have gotten too low the very first time, as I was starting to hear rear end humming. Could the gears have become damaged, and somehow the new seal keeps losing it's sealing power??

Does anyone know what I should do??? Thanks.

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I'm new to these Buicks but I'd guess things aren't much different under there from a Chevy. It sounds like there's a groove in the yoke that slides over the pinion. You may have to replace or 'sleeve' that thing to get it to work. Your shop should have told you if this was the case, particularly after they took it apart the second time.

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I took the car to a questionable mechanic. I'm not sure if he used the exact Buick replacement seal. And I'm also not sure if he used the correct gear oil for the Posi rear end.

I also don't completely understand what you mean by "sleeve that thing up". I guess I may have to take the car to a rear end specialist..

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The "sleeve" is a piece of thin tubing (usually stainless steel) that snugly slips over the seal contact area of the shaft to basically give the seal a "new" surface to work with, instead of the existing surface which could have a wear groove in it from seal contract. The seal rubs against the shaft to seal the area and keep the grease inside. Such sleeves are very common for the front of crankshafts.

Now, if the correct GM/Buick part was used, it would place the seal contact area in the exact same place as the previous seal had been (i.e., "in the groove"). Some aftermarket seal manufacturers have configured their seals to move the seal a little forward or back of the original seal contact placement so their seal is not trying to seal the previously grooved area. I don't recall who makes them, but they've been around for a good while, but maybe not for your application. One of the first applications was rear axle wheel bearing seals so they probably are out there for the pinion seal too.

Hope that helps . . .

NTX5467

All rear axle lubes are now "universal" and go in PTracs as well as "open" rear axles, you just add the GM PosiTrac additive to the grease. That will not cause the seal to leak.

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You're welcome. Be sure to get an opinion on the seal surface while they have it apart too. Hopefully, they will have some sort of "driving tool" to make sure the seal goes in "square" and not cocked somehow as poor installation can also cause problems.

Enjoy!

NTX5467

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NTX5467,

Thanks for being so helpful about this. I wonder if I could ask you one more question.

What are the chances of rear end gears becoming damaged if they run for too long with too little gear oil in the differential. I have a feeling this was the case before the first time the seal was changed, and it was refilled with oil.

There is humming coming from the rear end that does not seem to go away. Happens at low speeds, around 25 miles per hour, and then at around 60, while gas is applied, stops while letting the gas pedal off. Thanks

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Thanks for the kind words.

I suspect that if it's a steady hum that it could be a gear-related noise. It would probably be best to take a look at the contact "face" of the ring gear teeth for wear patterns--on both sides of the teeth. To get a better picture of that situation, you will need some "gear marking compound" which will make the contact pattern easier to see. GM still sells such a compound, but it's not the colored lead as in prior times.

It might be that you can reposition things with shims to get a more even contact pattern on each side of the gear (as it should be). Sometimes, when it's gone too far, it will take a new gear set properly setup. Someone that knows what they are looking at will need to make that determination, though. There are also some rear axles that have a slight hum in them from the factory, which is usually louder under cruise and not coast situations.

In reality, I suspect that unless the lube level was basically empty, low lube levels might not be that critical unless the vehicle was operated at high speeds under heavy load while it was low. Probably even with just one quart of lube in there, the ring gear would still run through it unless it had slung it all around and it was slow to drain back, but with higher loads and higher speeds the drain back time in this scenario would be critical. In other words, with it being just a little low might not be that critical.

I guess that for now, the very least diagnostics would be to pull the rear cover and look things over (ring gear teeth) and do a pattern check. Again, with someone that knows what they are doing and what they are looking at making the diagnosis. Once that is done, then a determination can be made to go further or not.

Other than the gear contact pattern, also look for evidence of excessive heat on the gears--as evidenced by different colorations in the metal that normally would not be there. That would also be evidence of low lube levels.

Hope this helps . . .

NTX5467

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  • 2 months later...

Hi everyone!

I was reading the diff seal thread and wanted to ask another question. I just bought a 70 GS and the rear end is leaking...and it looks like the pinion seal is the culprit. I'm going to replace it myself and I was wondering what's the best technique to get the old one out?

Derrick-Denver, CO wink.gif

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My two cents worth on the noise in the rear end is as follows:

When the person that replaced the pinion seal did the job, he tightened the pinion nut over what it was originally set at, pulling the pinion gear further away from the ring gear and this changed the gear set mesh. There is a spacer between the bearings, sometimes called a "crush sleeve". This was probably compressed further at the time.

You may be able to reset the gears, depending on how much wear is on the gears set, and how long they were mis-meshed.

Good luck with this, hope this helps you.

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