jtb032295

Hey guys, I recently replaced a 4L60E and it is now leaking from the bellhousing. It immediately began to leak from the front inspection hole. The pump was a reman unit with a "new stator support" and the internals were upgraded with the HD sunshell, 3-4 band, and a shift kit. I also installed a new 2600 FTI converter while I was there.

I've heard that the front pump bushing can walk out and cause the front seal to leak. Is this something that would actually happen with a fresh reman pump? I'm hoping I just damaged the seal when installing the converter. I'm thinking it could also be the pump cover seal?

Any suggestions? I'm going to attempt to get an inspection camera inside the bellhousing to see exactly where it is leaking.. I don't know what I could've done wrong...

Jays_SSZ28

iTrader: (2)

The bushing won't walk out because there is a small lip in the bushing bore on the outside.

I've had a leak around the pump o-ring caused by a very small nick in the case right where the o-ring seals, it wasn't that big of a leak.

I would guess it's more common to have damaged the seal during installation.

jtb032295

Is this true for all 4L60Es? I've heard that newer units have the lip to retain the bushing but not older ones?

Jays_SSZ28

iTrader: (2)

Newer as in what? older as in what? What do you have?

The truth is it's not going to fix itself. You're going to have to take the transmission back out.
Take it out and find the problem. Could be the bushing I guess, could be the seal, could be the pump o-ring.

I've seen people on forums say it ended up being the dipstick seal, the cooler line, etc.

jtb032295

This was something I "heard," not a fact. I'm unsure of the year that the update was made to include a lip in the bushing. I was asking that question... Do all 4L60Es have the lip for the bushing or did they previously, at some point in time, have no lip allowing the bushing to walk forward?

It is definitely a leak from inside the bell housing, as it is clearly running out of the inspection hole. I fully intend on tearing it back apart to find the problem. Honestly, I was hoping to hear that it is unlikely for a bushing to walk on a new unit. I will be taking it back apart, trying to find the leak in the next few days.

2ToeRacing

iTrader: (5)

Could be the torque converter

PBA

Starting in 1987, they added the lip to keep the bushing from coming forward, and they opened the drainback hole for the torque converter. In apx. 1992-3 they went to the Teflon bushing and that was a major improvement over Babbitt type of material which could grab the torque converter hub and spin and would wipe out the front pump. I have never seen a Teflon bushing spin as there is nothing for the torque converter hub to grab on too.

jtb032295

Thanks for the help! Yesterday, I took it back apart and found no apparent issues. The front bushing was not against the seal and looked to be new. The seal did not look bad. I replaced the seal anyway and checked everything over, reinstalled the converter and trans, and it still leaks just like it was before.... I can only think that it's the outer pump seal.

I placed a plastic cap over the torque converter, while it was out, and pressurized it with 10-20psi of compressed air. I saw no leaks

2ToeRacing

iTrader: (5)

Check to make sure the pump bolts are tight and that they have some form of sealent around them. I remember the 700 had washers on the bolts but I cant remember what the 4l60 have.

mrvedit

Yes, the pump bolts should have an o-ring type seal on them.
You can safely remove 2 of them at a time, check the seals and torque them to 19-24 ft/lbs.
Hopefully the rebuild didn't forget the gasket between the pump and body.
If you decide to pull the trans again and remove the pump, we can give you some advice on how to do that without pulling half the internal out with the pump.