Rear main seal

[Peeledpeas]

I just replaced my rear main seal while I was swapping the transmission a couple months ago but it appears to be leaking already. Is there anything else that could leak that might look like a rear main leak? I can definitely see a stream of oil comin down behind the flex plate. I'm pretty sure I got a good look at the oil pressure sensor and it doesn't appear to be leaking. Kinda really annoyed about this. Was a Felpro seal set with cover gasket and I followed the instructions. 2005 GMC Yukon 5.3L

 

[mountie]

I just replaced my rear main seal while I was swapping the transmission a couple months ago but it appears to be leaking already. Is there anything else that could leak that might look like a rear main leak? I can definitely see a stream of oil comin down behind the flex plate. I'm pretty sure I got a good look at the oil pressure sensor and it doesn't appear to be leaking. Kinda really annoyed about this. Was a Felpro seal set with cover gasket and I followed the instructions. 2005 GMC Yukon 5.3L

Ouch...... Something failed...... Get it on a lift..... clean the area good..... maybe you'll find it?
Sorry to hear, you might have to do it all again..... Bummer....

 

[justirv]

I just replaced my rear main seal while I was swapping the transmission a couple months ago but it appears to be leaking already. Is there anything else that could leak that might look like a rear main leak? I can definitely see a stream of oil comin down behind the flex plate. I'm pretty sure I got a good look at the oil pressure sensor and it doesn't appear to be leaking. Kinda really annoyed about this. Was a Felpro seal set with cover gasket and I followed the instructions. 2005 GMC Yukon 5.3L

Installation of a LS rear main seal can be problematic. Did you use any type of alignment or installation tool? Something like the Sac City tool, which will align the cover and seal to the block. If you find this (rear seal) is the problem, I highly recommend one. Good luck.

 

[drdave81]

Yep, if you didn't use the alignment tool, the trans is likely coming back out. Gonna have to redo it unfortunately.

 

[Peeledpeas]

Installation of a LS rear main seal can be problematic. Did you use any type of alignment or installation tool? Something like the Sac City tool, which will align the cover and seal to the block. If you find this (rear seal) is the problem, I highly recommend one. Good luck.

I was unaware of needing an alignment tool. There was a round plastic thing that came in the Felpro set but I take that may have been inadequate for the task?

 

[Peeledpeas]

Yep, if you didn't use the alignment tool, the trans is likely coming back out. Gonna have to redo it unfortunately.

I did it on jack stands last time. I'm hitting up my buddy that has a lift this time. That was a major PITA.

 

[OR VietVet]

Sorry to hear about this. The alignment tool is slick. If you have a lift, unbolt and shift transmission back and suspend it in some way or use adjustable tall stands.

 

[drdave81]

I was unaware of needing an alignment tool. There was a round plastic thing that came in the Felpro set but I take that may have been inadequate for the task?

That's not an alignment tool. It's just to keep the seal surface intact. The alignment tool is usually aluminum. You remove the old seal and then when reinstalling the cover, place the tool in where the seal would go. Bolt everything in place and torque. Then you install the seal last.

 

[89Suburban]

I never heard of this alignment tool for the rear main. Is this all LS motors?

 

[latvius]

LS Rear Main and Timing cover AlignIt Tools

Must have tool for aligning the rear main and timing cover on the GM Gen III & IV LS based engines to eliminate premature seal leaks.

www.saccitycorvette.com