Confirmed that the radiator is leaking due to a crack in the plastic tank on the drivers side. New radiator ordered, and looking at what else I should replace as part of the job. The engine oil cooler lines are fine but the transmission cooler lines are leaking at all the crimps. This truck (in signature)actually has 2 trans coolers, one in the radiator and another external cooler that sites in front of the a/c condenser. So the cooler lines go from the trans to the rad, the rad to the external cooler, and then back to the trans, 3 lines altogether.Anyone offer any pointers/advice on changing these lines? I just had a Jasper rebuilt trans installed in Sept and asked them to check the cooler lines and thought for sure they would replace them but they didn't. They did say they flushed the lines and coolers prior to installing the new trans.Are these lines hard to get out of the transmission?This is the line coming out of the top of the radiator, this is typical of every place hose is crimped to hard line on all 3 lines. Should I replace them or leave them?

I wouldn't take a chance, Replace them.

Any info on how the line come out of the trans and whether they are hard to remove would be appreciated.

Very common complaint on a lot of GM products for several years. It was easier and more profitable for GM to leave these bad crimps as they were vs. coming up with a better design that wouldn't cause problems. Falls into the same category as their fuel pumps, intake manifold leaks, alternators and so on. Change them out with a new set and expect the same failure in a few years. I USED to drive nothing but GM products..B.O.

BurbMan, I just installed a large transmission cooler this summer and I took a die grinder with a abrasive wheel and cut the crimps and removed the hose. the metal fittings have a barb and you can get new rubber line, 5/16, and use hose clamps to secure. Put 7500 miles on and no leaks.Good luck.

GeoBoy wrote:BurbMan, I just installed a large transmission cooler this summer and I took a die grinder with a abrasive wheel and cut the crimps and removed the hose. the metal fittings have a barb and you can get new rubber line, 5/16, and use hose clamps to secure. Put 7500 miles on and no leaks.Good luck.I did the same thing to mine last year. I would feel much better with an adapter (are any made?) to connect some braided hose . If one of the rubber hoses fail you are stranded and will probably need a new trans.

4L80E Cooler Lines | Good Sam Community

camping_man
Explorer
Dec 12, 2013
I usually spin a small pipe cutter over the line, to cut it without burrs. Then put a small flare on the end of the line, with a flaring tool so the a new rubber hose will stay on with a coupe hose clamps. I never had one go bad on me like this.
BurbMan
Explorer II
Dec 12, 2013
I got a Christmas card from Rock Auto today....LOL no kidding! Trying to keep a 1998, 2 2001's and a 2005 on the road...
texasclarks
Explorer
Dec 11, 2013
BurbMan I would live to know who it goes as I need to do mine soon and not looking forward to having to pay GM an outrageous price to do it.

If I was back in Kansas where I have access to lifts and help it would be a no-brainer but moving to WV and don't have access to the do-it-yourself shops on an Army Base.
Heisenberg
Explorer
Dec 11, 2013
Burbman has it ... Rock Auto ...
BurbMan
Explorer II
Dec 11, 2013
After much searching, there are no aftermarket lines to be had. The 8.1 in the Suburban is a different installation than in the pickups, and sometimes parts are hard to find. Items that are generic to the 8.1 are generally easy to find and have good aftermarket choices (VistaPro Radiator for example). But some items that are specific to an 8.1 in a Suburban don't make it into aftermarket inventory because the demand just isn't there. Both Dorman and Edelmann make trans cooler lines, but not for this application. Engine oil cooler lines, yes, but not trans cooler lines.

Sooooo.....bought the Delco lines from Rock Auto at $13 each. Installation at the trans doesn't look too bad. Removal of the lines, the shop manual indicates using a pick to pull out the wire clip, the caveat at doing it this way is that the clip must then be discarded. I am headed out of town so hopefully will dive in this weekend when the parts start to show up. Will keep you posted.
carringb
Explorer
Dec 09, 2013
I always convert them to soft lines. NAPA has adapter fitting with hose barbs. I use Nitrile hose because it holds up to heat better never hardens like rubber lines.

Those lines OE-style hard are difficult to source aftermarket, GM wants way too much, and they will eventually end up in the same condition anyways. And on some of the trucks, like the TrailBlazer, you have to drop the crossmember to swap the lines.
mapguy
Explorer
Dec 09, 2013
This is my fix on the Duramax/Allison transmission lines. Not sure if the cooler lines are the same diameter on Suburbans....

FC300-10 Aeroquip hose
2x per hose FC2875-10S NUT VersilFlare Tube OD .63" FLARELESS

2x per hose FF9605-10S NUT VersilFlare Tube OD .625" FLARELESS

2x per hose 4414-10S SAE JIC (37 Deg) Male Flare 100R5 Reusable Fitting. Use this as a setting tool for the flareless fittings, too.

I have purchased aeroquip from the link below:

http://HoseWarehouse.com
texasclarks
Explorer
Dec 08, 2013
BurbMan wrote:
I changed the engine oil cooler lines with Edelmanns a few years back and they are dry as a bone still. I have had no luck finding aftermarket lines but will check out the Parker line.

Is the quick release tool for the trans lines different than the ones for the Fuel and A/C lines?

I noticed my oil & trans cooler lines are 'wet' but not dropping to the ground (class II leak). I need to replace them after we finish out move to West Virginia. I would be interested in finding where you bought the lines and how hard they were to do yourself.
BurbMan
Explorer II
Dec 08, 2013
I changed the engine oil cooler lines with Edelmanns a few years back and they are dry as a bone still. I have had no luck finding aftermarket lines but will check out the Parker line.

Is the quick release tool for the trans lines different than the ones for the Fuel and A/C lines?
Passin_Thru
Explorer
Dec 08, 2013
Go ahead buy the kit and have the same problem in a few months. I bought Parker hoses online and never looked back. I hate Chevy for their cheap crap. Dig around on Chevy Duramax forum and youll find Parker hoses. Its not that hard to replace them but use the proper wrenches and make sure you use 2 wrenches as the cooler will bust and cost you another arm and leg.

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