Hello all, my girlfriend has a 1999 Chevy Silverado 1500 Z71 with an automatic transmission. Last August she had to have the transmission rebuilt by a local indy shop to the tune of $1800. The other day, for the first time, I drove the truck and noticed a ticking sound suggesting that her oil may be low, so I checked it and had to add 3 quarts to bring up to full. When I asked her about it leaking, she said it never has not has she ever had to add oil. I slid underneath and noticed the rear main is deffinately leaking. My question is could this have been a result of the transmission rebuild? The work has a 1 year warranty but I wanted to check here before I called the shop to inquire. I've only been seeing my girl for about 2 months, so my knowledge of the truck's condition is limited. As always, thanks for any help!
Rear main seal leak after transmission rebuild
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ls1mike
$50 Site Donor 2024
How many miles. It is common for them to leak when they get old but 3 quarts? That is a big leak. I am surprised they didn't change while they were in there.
Nope.no reason for them to touch that seal when rnr the trans. Try a high milage oil before condeming the seal.
ls1mike
$50 Site Donor 2024
Don't know who does your transmission work, but the guy who does mine changes them. It is part of the quote.
Originally Posted By: ls1mike
Don't know who does your transmission work, but the guy who does mine changes them. It is part of the quote.
+2 Always change out that seal. You are looking right at it. It's like changing the water pump with a timing belt job.
Don't know who does your transmission work, but the guy who does mine changes them. It is part of the quote.
+2 Always change out that seal. You are looking right at it. It's like changing the water pump with a timing belt job.
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It's possible that when they went to reinstall the trans that they nicked the seal and now it's leaking.
But I agree, 3 quarts leaking out of the RMS would be quite the smoke show when it hits the exhaust.
Did the shop also change her oil for her and not fill it all the way?
But I agree, 3 quarts leaking out of the RMS would be quite the smoke show when it hits the exhaust.
Did the shop also change her oil for her and not fill it all the way?
I'm guessing that the 3 quarts have leaked out since August, when the work was done.
IMO, it's pretty hard to nick the seal or the sealing surface of the crank during a transmission R&R unless the flex plate was removed.
Maybe the seal was replaced but incorrectly. It's kind of counter-intuitive, but after '97 model year (inclusive), GM specifically states NOT to lubricate the seal lip or sealing surface of the crankshaft when installing the seal. I don't know why this is, but it must have something to do with the seal lip being made of PTFE. The Fel-Pro replacement seals I've used also include instructions stating this.
The leak could also be coming from the rear main seal housing that is bolted to the rear of the block.
Maybe the seal was replaced but incorrectly. It's kind of counter-intuitive, but after '97 model year (inclusive), GM specifically states NOT to lubricate the seal lip or sealing surface of the crankshaft when installing the seal. I don't know why this is, but it must have something to do with the seal lip being made of PTFE. The Fel-Pro replacement seals I've used also include instructions stating this.
The leak could also be coming from the rear main seal housing that is bolted to the rear of the block.
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