US MARINE, 2004 CHEVY TAHOE LT RWD 5.3L 4L60E

Hello everyone,

I am having some problems with my 4L60E. Just rebuilt it but now it's kicking out fluid from the low side of the vent hose.... any help would be greatly appreciated.

I have checked, I'm not over filled. Also the transmission isn't getting hot. I'll start the Tahoe shuffle through the gears staying in each gear for approximately 2-3 seconds each, then get out and look and the fluid is just flowing out.

Please help

Respectfully,
J.Kleven

"sherlock9c1" is the resident transmission guy. He drops by regularly, might miss a day here and there. You could PM him, but I believe you need 5 post.

Actually, I will PM him and let him know of your post.

Tom

Thank you so much, I'm still new here and trying to figure out how this all works.

I'm planning on pulling the transmission out tomorrow and go thorough the pump and valve body again to make sure nothing is binding up.

Are you checking the fluid level properly? With the engine running, trans warmed up, on level ground with the trans in P?

Yes sir, I have been making sure it's on level ground transmission is warm in park and it's right in the hash marks.

Just to be clear, it's coming out of the rubber vent hose that attaches to the port on the very top of the transmission? That's literally just an air vent directly into the case (which, BTW, is why you should ALWAYS have that long vent hose installed on the transmission. It acts as a filter to keep junk out but still let the trans breathe).

If fluid is being pumped out of there while it's running, the fluid level is too high, the fluid is being aerated, or something else weird is going on. Fluid literally has to be slung against the top of the case so much that it forces it into that little opening and then out the hose. You're SURE it's coming from there and not somewhere else? Drastic leaks only while running could be cooler lines, the converter seal/bushing, or the line pressure test port on the driver's side of the 4L60E.

Yes sir, I have crawled under to verify. That VENT hose off the top of the case goes to a "T" one side RUNS along to the tip of the transmission bell housing and at the end is a plastic vent, however the other end runs down the rear drivers side of the transmission along the frame for the transmission mount and mounted near (just a lil in front) of the fuel filter and fuel lines where from everything I have read states is in case of over filling or over heated fluid. Sorry this message was so long just want to try and describe the layout

What's the fluid look like? You sure it's not getting coolant or motor oil pumped into it somehow?

Fluid looks clean and red, it's brand new fluid from when I did the rebuild I haven't even ran the transmission for 10 miles because of how the fluid is just gushing out of the low side vent hose. I will say though the transmission shifts perfectly and smooth, I can feel that power is there but because of the fluid coming out I can't do a full road test.

Yeah, it's gotta be overfilled. Maybe the wrong dipstick is in it?

An alternate approach is to pump the pan out, then only refill what's in the pan. The B-bodies never pumped out more than 3 quarts if I recall correctly, and they had pretty shallow pans.

Try opening up a cooler line up front, buy some clear plastic hose, put it over the lines and aim it into an empty milk jug, then start up the truck to pump it out. Once it sputters, only put 3 quarts back in and see if that fixes it. Maybe add a quart for the truck pan that's deeper than a Caprice/Roadmaster pan?

Ok thanks I'll give that a try. I will say though I have the stock dip stick still in it

I have heard of plugged cooler lines causing fluid to come out of the breather, but never seen it in person to verify. Could be something to look into. Its also SUPER easy to overfill, especially with new fluid. I have a hard time reading the dipstick sometimes when its fresh and almost clear. I usually pull the stick at least 10 times to verify I have a good level.

Thank you, I'll check the cooler lines as well. I think ultimately I'm going to have to end up pulling the transmission out again and go through the pump and valve body again to make sure nothing is sticking. Just not looking forward to that.

I don't think that's your issue.

Try my cooler line drain and refill trick first.

Do you have a line pressure gauge? Those are invaluable for diagnosis and relatively cheap. Get a 0-300psi gauge; I bought one off ebay years ago and still use it. Hook it up to the driver side pressure test port and see if you're getting around 70psi at idle in Park.

Yes I have a gage, but I'm not sure where exactly that port is. If you have a pic that'll be great otherwise I can look it up when I get back later today.

It's the only port on the driver's side, above the shift shaft.

Ok sorry I haven't been on in a while, I was on T.A.D. away from the car (and family). I did try the cooler line fluid swap before I left, still kicking out fluid from the vent hose. So now that I'm back I pulled the transmission back out, I did notice the top trans cooler line was bone dry. I've got the trans out and planning on going through the valve body and maybe pump to se if anything is sticking.... Any ideas?