4T60E transmission leak question : ( for you transmission experts )


New member
I have a 4T60E transmission on my 3800 '93 Transport. Rebuilt trans. at 130K . Transmission now (195K miles ) , leaks like a sieve on the left side of van . Redid the pan twice - that wasn't it . Noticed flow coming down left side , looked maybe like it was coming from left output shaft seal so I replaced it . checked splined output shaft in tranny for looseness and found none at all ( like it might deflect seal enough to leak because of worn bearing) . I am now thinking the red transmission fluid leak is coming from something ABOVE the left output shaft . My question is : what is above that area that would leak a stream of fluid , especially when I give engine more gas ? Is there some leak- prone device above there that I can replace without a $2600 transmission job ?


Active member
To find any leak you will need to clean up the transmission case and dry it off.

If you put the vehicle up on Jack stands and just run the engine and inspect for leaks, if none are found, turn off the traction control you should be able to run it up to a reasonable speed and inspect for leaks while someone is holding the throttle at the speed you desire 10-20 MPH should be enough to spot a leak if it is from the axle seal area.

The axle seal you replaced may have worn a grove into the sealing area of the axle.

If you have a reappearing leak at the seal you will have to pull the axle back out and look for a grove where the sealing lip rides on the axle.

If it has worn a grove you may find a repair sleeve or just replace the shaft.

Also some transmissions have a bushing just behind the seal that wears out and will cause a leak. But I am not sure if that applies to your transmission.

The point is do not just guess, clean the transmission case good check the fluid levels and inspect it for leaks. once you know for sure where the leak is coming from we can further advise you what to do.