Axle Seal and Transmission Leaks (2000 Auto Coupe)
I have a 2000 Coupe with 24,500 miles on it. It has an Automatic Transmission with a 3.15 rear. This C5 has lived a charmed life except for a couple of nagging problems somewhat common to the model. It has a reoccurring leak from the driver’s side rear axle seal, the axle seal housing and from the shaft seal between the transmission and the differential. The axle and housing seals fail about every 3,050 miles (on average) and have been replaced 7 times. The housing has also been replaced. So far the last repair done at 21,275 miles hasn't leaked. The transmission seal was last replaced at 23,124 miles in Oct. 2006 and started leaking again at 24,334 miles in May 2007. Replacing this seal is a 7 hour job and requires dropping the entire rear sub frame. My GMPP expired in April 2006 so the latest repairs have been “Good Will”, thank you GM. At this point GM is willing to replace the transmission at no charge, labor included. My question is should I replace the differential at the same time? The service manager has offered to sell me a new rear end at dealer cost ~ $1,000.00 and install it while replacing the transmission. Are there options or products that may have more reliability, strength and quality? Anything from SLP that might have a GM warranty? So that’s it any advice would be appreciated.
Location: Edmond, OK...One of the first rules of online forums: If you don't like what is said but can't refute it, attack the poster.
Are you talking about replacing the differential with different gears, like 3:42's? If so, then 1000 is a great price and it's even better with no labor charge. Thats a 300 to 500 savings right there! If you do it, you might want to change out your torque converter to a high stall.
Mike -- The last repair consisted of changing the left axle housing, the housing seal and the left axle seal. They used a "new" red anaerobic sealer that was supposed to reduce the incidence of leaking. The case was not changed.
Jeff – The $1,050.00 was for the same rear with 3.15 gears. The thinking is that either component may be causing the other to fail. There has been a high incidence of leaking from the driver’s side axle and housing seals. It should be noted that Bob at Fichtner Chevrolet quoted me $1,099.00 for the same part w/o shipping and core charges.
Another concern is the warranty. I am told it will be 12/12 on either component. Labor not included since I’m not paying for the labor. I have also been told that new GM transmissions have a 5/100 warranty on them. Nothing in writing yet.
Are you leaking transmission fluid or differential fluid?
Installed between the transmission and the rear diff on automatic equipped cars is an aluminum plate with 2 seals, these 2 seals only keep differential fluid where it is supposed to be and if you happen to be leaking transmisssion fluid at this point then it would have to be coming from the rear seal on the output shaft of the transmission.
So with that said replacing the transmission is a waste of time unless that happens to be whats leaking, I would definitely want the differential changed though due to the side cover constantly leaking.
Hey Robert: Thanks for your reply. The transmission is leaking at this point. It started leaking again in March (a little) after a 200 mile trip and again after a second 200 mile trip. The Chev. Service dept. had replaced the transmission to differential seal last October. When I took it in they declared it a weep hole leak and sent me on my way. I returned after it started leaking enough to coat the rear of the vehicle. They removed two trans bolts (what two I don’t know) put thread sealer on them and sent me on my way to see if it leaked again. It’s still leaking and the GM rep has offered to replace the transmission at no charge. They will also sell me a new rear end at dealer cost (it's not leaking at the moment) and install it at the same time w/o charge. My thinking is one component or the other is causing the failures. Either the trans is causing the rear end axle and housing seals to constantly leak or the rear end is causing the trans leak, or both. I just want a reliable car free of leaks!
Before someone jumps in and says every car leaks check out this list:
Sorry to hear about this, GM has had problems with leaking transmissions and differentials in the C5 and I think that problem was made worse by some GM techs that didn't properly repair and don't uinderstand how they are sealed.
If you are leaking transmission fluid, and it is coming from the joint where the differential bolts to the transmission then it can either be case porosity or a rear output shaft seal on the transmission. If its the output shaft seal then the only way to replace that is to remove the transmission, maybe someone will chime in that knows better but I don't think that seal can be installed properly with the output shaft in place.
As far as the transmission to differential seal goes, the only thing that seals is the differential. I have a transmission in my garage and I'll try to take a couple of pics of it and the seals so you can see for yourself what seals what.
Thanks again Robert. I look forward to the photos. And thanks for the thread; I printed all those photos for my later use. I am meeting with the Lead foreman today regarding this situation. This dealership has replaced the shaft seal and did indeed remove the rear sub frame to do it. But the repair only lasted for months. October 2006 to March 2007. The funny thing is I have a better warranty now than I will after replacing the components. Now I have a letter covering the Trans and Diff. from leaks or failure for 10 years or 100K miles. After the replacement I will have a 12/12 warranty labor not included because I am not paying for the labor. If it were customer pay, the warranty on the Trans. would be 5/100. I am unsure about the Diff. warranty on customer pay. Bob at Fichtner has been very helpful. I am calling LPE next for advise. The Vette would be there now getting their 435 hp package if not for this B.S.
This first one shows an automatic transmission with the differential and the seperator plate removed, you can see the seal on the output shaft and if this is leaking you'll get transmission fluid leaking from the joint between the trans and diff.
This picture shows the seperator plate close up, you can see the o-ring and center seal and if either one of these are leaking then you'll wind up with gear oil from the diff leaking.
This picture shows the seperator plate mounted on the transmission and at this point the differential would be ready to be bolted up.
All of these pictures show an automatic transmission, if you have a manual then just look at the last picture because that sperator plate is not needed because the back of the manual trans has it built into the case (so to speak).