• Welcome to The Truck Stop! We see you haven't REGISTERED yet.

    Your truck knowledge is missing!
    • Registration is FREE , all we need is your birthday and email. (We don't share ANY data with ANYONE)
    • We have tons of knowledge here for your diesel truck!
    • Post your own topics and reply to existing threads to help others out!
    • NO ADS! The site is fully functional and ad free!
    CLICK HERE TO REGISTER!

    Problems registering? Click here to contact us!

    Already registered, but need a PASSWORD RESET? CLICK HERE TO RESET YOUR PASSWORD!

Leaking Tranny Lines

I replaced one of mine. Don't remember the part # but according to the service man it was the updated one that GM just put out to cure the problem. We'll just wait I see if he was telling the truth.
 
I replaced one of mine. Don't remember the part # but according to the service man it was the updated one that GM just put out to cure the problem. We'll just wait I see if he was telling the truth.
Were these "updated" lines available in late Jan.? That is when I got mine done. Hope when the cold comes back, I don't have the same problem.
 
Every LBZ has the possibility of leaking. They leak mainly or only in the winter months when its cold. the lines shrink or something due to the cold. i got mine replaced right after they stoppe leaking by themselves when it got warm again. My bros, my dads, my buddies, and my other buddies 07 classics all leaked untill it got warm again. The "updated" lines are i belive no different and still leak from what i remember hearing. we will see come cold.
 
Bump to the top. Got my 1st leaker at 81k+ miles on the pressure line to the bottom of the radiator. Was running high idle to warm up a few times recently at below or near zero. IIRC the Canadian guys got a letter last winter telling them to disable high idle because of it. My bad I guess.
 
Bump to the top. Got my 1st leaker at 81k+ miles on the pressure line to the bottom of the radiator. Was running high idle to warm up a few times recently at below or near zero. IIRC the Canadian guys got a letter last winter telling them to disable high idle because of it. My bad I guess.

Mine are still leaking. I had a appointment for the dealer to fix them, But I still haven't got it down there yet.
 
Leaking trans lines

Hi ! There are new part numbers for the 3 lines- the new lines have different crimping to seal better-time will tell ! Put on 9 lines today ! See ya !:)
 
leaking trans lines

hi ! part numbers for the new updated trans lines are upper #20759971 - lower #20759972 - to cooler #20759973 these lines have a updated crimp these new lines are about $50.00 each in canada see ya! BUBBA JIM:)
 
Bump to the top. Got my 1st leaker at 81k+ miles on the pressure line to the bottom of the radiator. Was running high idle to warm up a few times recently at below or near zero. IIRC the Canadian guys got a letter last winter telling them to disable high idle because of it. My bad I guess.

Mike, mine are leaking pretty bad in the same spot. Everything is pretty oily under there now.

I got to get down and have them replaced..

So, have these new "updated" lines fixed the problem?
 
So far so good Jeff. It's only been a couple of thousand miles since I replaced it thanks to some good advice from Noah. I wrote up a DIY (but no pics) and I don't remember if I put it here. Let me know if you need it. When I compared the 2 side by side there wasn't much difference between the new and old part #s except the new crimp appeared a bit better quality.
 
So far so good Jeff. It's only been a couple of thousand miles since I replaced it thanks to some good advice from Noah. I wrote up a DIY (but no pics) and I don't remember if I put it here. Let me know if you need it. When I compared the 2 side by side there wasn't much difference between the new and old part #s except the new crimp appeared a bit better quality.

Post it up here if you don't mind, I'd like to take a look at it.
 
This was on my '06 GMC. Took 4 hrs but with this it might be 2 1/2 or so.

1st you'll need:
New retainer clips (3 or 4). I didn't lose one but can see it happening.
Several fender liner fasteners. You'll ruin a few.
Plastic or vinyl caps (1/2") to go over the tube ends to keep crap out.
3 or 4 qts of DexIV or what you use.
Lots of patience...
Full set of tools beyond the normal Sears set.

Jack it up and take the RF off. Remove the front 1/2 of the fender liner and tie it back. Remove the splash guard in front of that. Take out the air box (it just pops out with a good tug. Remove the airbox mount plate and L bracket it mounts to (1/2 doz or so M10 head bolts). Pull the double U shaped plastic clip that holds the 2 lines apart (from underneath) at the back of the radiator. Pull the clip at the trans with a small pick and pull out the line. It will drain about 3 qts over time. At the side of the block is a bracket that holds the 2 lines. Use a small 1/4 " ratchet and 10mm socket to loosen the nut above it and spin it off by hand. Pull the clamp down and rotate it until you can get a large blade screwdriver into the split at the top of it to pry it apart. Make sure the rear 1/2 of the line moves around freely. Pull the front clip at the radiator. It's right between the lower hose and the CAC return line and really tough to get to. I used a small electrician's screwdriver to pry it up enough to get a pick with a hook on the end under it so as not to lose it. Grab the hose from below and wiggle it around until you can jockey the hose end out of the radiator. I think I used a wooden stick to gently pry it. It will drain about a pint. Slide under and look up where the lines go through and you'll see a triangular shaped opening where the double U shaped clip was. The line will come out fairly easy if you cross it over to the other side of the return line and snake it down while working the hose area and rear line around. The whole assembly comes out the back over the steering arm, axle and crossmember. Put the new (preferred) or used clip in the radiator fitting and make sure the detents are all the way into the 3 slots. Put some caps over the ends of the new line to keep the inside (and outside) clean and put the line back in the same way you pulled the old one out. Once you have it located, pull off the front protective cap, start the fitting into the radiator nice and square. When it looked about ready to go in but I couldn't get any leverage, I put a short (3/8 x 1 x 6") piece of wood square to it and gave it a tap with a small hammer. It will click into place. Slide the double U shaped retainer back up there and reinstall the block support bracket. Put the clip into the trans fitting in the 3 slots, pull off the end cap and push the tube in. Put all the rest back together and dump in a couple of qts of DexVI (or what you use) and fire it up. I wound up using 3 qts total after it was up to temp. This was an '06 GMC LBZ so the Chevy trim and an LLY may be somewhat different. I think the leakers was an LBZ thing anyway.
 
Anymore updates? Mine are leaking at 26983 miles. Have started leaking within the past few months and my warranty is up since my truck is a 2006.
 
Back
Top