Transmission cooler lines - leaking AGAIN

[KenR]

I've been told this issuse has something to do with cold weather idling.

I dunno - Mine started leaking again right when the weather started cooling off a bit, but I wasn't idling the truck any more than usual.

[madmatt]

I dunno - Mine started leaking again right when the weather started cooling off a bit, but I wasn't idling the truck any more than usual.

IIRC, it had something to do with the convertor locking up while in neutral and the tranmission cold mode to help warm things up quicker on cold starts.
An Allison engineer and I were talking about this during a traning session last winter. But I can't recall the whole explaination he gave me. It was more then just poor quality lines though.

[DmaxMaverick]

IIRC, it had something to do with the convertor locking up while in neutral and the tranmission cold mode to help warm things up quicker on cold starts.

Hmmmm. This is interesting....And counterintuitive. During the cold mode (warm up mode), the TC remains open to expedite transmission fluid warming. The open converter allows for more fluid friction. Locking the converter would reduce this effect. Although there is very little TC resistance in neutral, it is still more than none.

An Allison engineer and I were talking about this during a traning session last winter. But I can't recall the whole explaination he gave me. It was more then just poor quality lines though.

Poor line quality. The line components are capable of handling significantly more pressure than the tranny will ever produce. The failure is at the crimps, lending to the likelihood of a question of quality. This isn't new. 6.5/2L oil cooler lines saw the same process. GM went cheap with the lines. Simple as that.

Although we shouldn't have to mess with this, the best solution is to just replace the crimp connection with a known quality repair. I recommend using Aeroquip type hose fittings, with a flare on the line. It is not expensive to do (you can do it yourself, or have any speed shop or AG supplier do it), and will never have this problem if done correctly. A second option is the same for 6.2/5L oil cooler lines. Remove the crimp collar and use hose clamps on the barb. Less permanent, IMO, but better than continually replacing the lines waiting for GM to get it right.

[KenR]

Just curious...does anyone know what the maximum pressure the transmission cooler lines will ever see?

[Stlheadake]

...A second option is the same for 6.2/5L oil cooler lines. Remove the crimp collar and use hose clamps on the barb. Less permanent, IMO, but better than continually replacing the lines waiting for GM to get it right.

I dunno about that. I did EXACTLY that on my wife's LeSabre. Lasted for about a year, then blew off. AFTER fixing on the side of the road, I 'permanently' fixed it by re-clamping and WIRING both sides so they can't pull apart.

Then I sold it...

[jbplock]

I dunno about that. I did EXACTLY that on my wife's LeSabre. Lasted for about a year, then blew off. AFTER fixing on the side of the road, I 'permanently' fixed it by re-clamping and WIRING both sides so they can't pull apart.

Then I sold it...

I've done the same fix (with two clamps side by side on each barb) on my daughters Saturn and Wife's Impala .. haven't had one come off yet but I still keep checking them frequently for any signs of seepage ... Several years ago I used the double clamp fix on a low side AC line for my 85 golf diesel.. a new line from the the dealer was over $100 .. I evacuated and recharged the system and it was still working when I sold the car a few years later..

[gophergunner]

So here's my attempt at a fix...

First I used a tube cutter to cut the tubing as close to the hose crimps as possible to get the hose section out of the line.



Then I went to town and got a piece of braided hydraulic hose made up with compression fittings. And just for the record, I was told these compression fittings are supposed to be able to handle 3000 psi or more, as they are regularly used with agricultural equipment. Thats what the guy at the parts store tells me anyways.





And here it is just loosely assembled, I won't tighten the fittings up until its all in place and fits properly into the truck.



I hope these work, well I'm quite positive they will hold, I just hope they fit in properly. I just need to go to a hunting store and get a wire brush for cleaning shotguns and scrub out the new hydraulic hose to make sure I get the loose bits out of it. Shortly after I install them, I will be taking my truck to the dealer for transmission service.

I do have another line to do, just took pictures of the one though.

[jbplock]

Looks Great .. excellent idea!

[Splitrimz]

Excellent job, great photos. Please update and let us know how it is progressing.

Splitrimz