Transmission front pump seal replacement

[dan1977p]

I've had an odd fluid leak that I've been hunting down for a while. The next step that I think is to replace the front pump seal on the transmission. I just replaced the rear main hoping the leak would subside and the area around that seal is perfectly dry but I'm still getting fluid coming out of the bell housing.

Main question, how hard is it to replace this front seal? On or off the Jeep? I've been wanting to drop the tranny so I can clean everything up under the jeep as well as clean it up so I may pull it anyway with the TC so I can reseal the TC properly too.

You can stop here if you don't care about the back story.

It only blows fluid if I've been running 80mph (3000rpm) for at least 10-15 minutes after it's warmed up completely. Once I've been running 80 for a while and let off the gas, I get a huge steam/smoke cloud out the back from fluid being dumped onto the exhaust and it completely covers everything behind the bell housing and I can't tell if it's ATF or engine oil. It's redish right now since I just cleaned as much as I could but I used AMSOIL for the engine that also has a red tint to it so... I've cleaned everything up from the valve cover down and there aren't any leaks prominent enough to cause this much loss smoke and it only happens after long high RPM runs so it seems more like something with the crankshaft anyway. Also when I let off the gas, I get a good vibe that I've always attributed to a slight misalignment of the rear DS, but maybe it's a bad bearing at the front pump that's caused that seal to fail but it only dumps fluid because maybe I'm sumping that pump? Any advice is appreciated.

 

[Ecomike]

Add a transmission cooler in the lower front first, and Google "Transmission fluid foaming cavitation and leaks overheating", I read some real interesting input on that cause recently. Seems if it gets too hot, the tranny fluid, it foams easily and cavitates in the pump, and then throw up fluid. Air velocity/pressure may be holding the fluid up in the bell housing till you slow down.

 

[Ecomike]

Also make 100% sure the fluid level is not too high or too low, find a flat grade, get the engine up to operating temps, run the transmission in neutral to get the tranny fluid up to engine temps for about 15 minutes. Then make sure you have the right dip stick and the right transmission setting for the dip stick to check the level. Some Tranny fluids may be better than others for running hot under heavy loads? Or try additives maybe????

"CAUSES: Transmission Fluid Leak (See Transmission Fluid Leak below) ... SYMPTOMS: Too much fluid will cause the fluid to foam, which may cause"

http://myautomatictransmission.com/what-can-go-wrong-with-an-automatic-transmission.htm

 

[Ecomike]

Some good ideas and explanations here

https://www.atsg.us/atsg/blog/haveyouenhancedyourdiagnosticchecklistlately/

 

[dan1977p]

Cool, thanks, Ecomike. An additional was on my list until my exhaust hangars broke and took out my muffler and tail pipe. I'll see if I can find a low mileage explorer and pull one when I get back in a couple weeks. I'd like to replace all the cooler lines while I'm at it and the quick connects are so dirty I couldn't get them released at the transmission side I may have to drop it anyway just to get them out and be sure I don't introduce a bunch of dirt in there connecting the new ones. Cooler does seem easier than replacing that seal so hopefully this will be the case.

 

[Ecomike]

I take it then that it does not have a cooler? In that case I strongly recommend one first. Word of warning the QCs on the cooler lines to the transmission, they are a biatch to get loose and to reinstall. I have nightmares about reinstalling them. Also took me a month to find the new ones somewhere. I forget the details, plastic QC with two o'rings. They are a special odd size!!!! Check Dorman on rock auto or one of 4x4 places on line like Morris.
Thought I had the new one in only to wake up the next day to 6 quarts of fluid on the driveway. Easy to get an o'ring hung up too on the install.

Also make sure there is no exhaust pipe-cat issue overheating the Trans casing (you mentioned a busted exhaust system?). I have solved two leaks like yours on a ford and my 87 XJ that were oil leaks caused by superheated oil, exhaust blowing on the oil filter (ford) and on the oil pan block (87 XJ). The ford would dump oil just like yours, exact same conditions. I was told the rear main seals were bad, but it was an exhaust leak due to bad engine mounts.

I would think if you had a bad seal it would leak most of the time. I had a front seal leak on a 73 ford LTD that had sat in the driveway for years with very little use and the shaft settled into the seal and it leaked more if it sat than if it was driven, New fluid and Trans-x to swell the seal a little, fixed it for 8 years and 60,000 miles

Cool, thanks, Ecomike. An additional was on my list until my exhaust hangars broke and took out my muffler and tail pipe. I'll see if I can find a low mileage explorer and pull one when I get back in a couple weeks. I'd like to replace all the cooler lines while I'm at it and the quick connects are so dirty I couldn't get them released at the transmission side I may have to drop it anyway just to get them out and be sure I don't introduce a bunch of dirt in there connecting the new ones. Cooler does seem easier than replacing that seal so hopefully this will be the case.

 

[dan1977p]

It's using the integrated cooler in the radiator.
I was planning on getting custom lines made when I did the external cooler anyway. I'll add a filter and temp gauge sender for giggles while I'm at it.

 

[Ecomike]

Let us know if it solves some or all of the problem.