Leaking T-Cooler

[NKlamerus]

The tranny cooler line has progressively grown from a drip to a leak as seen in the pic. If I disconnect that line, I shouldn't lose more fluid than whats in the cooler correct?

I also haven't found a "for sure" fix yet. A lot of people recomemd getting new hydraulic lines made,and some people just cut the hose and put a hose clamp on it.

Any suggestions?

 

[ScreaminDuramax]

Get the Upgraded trans cooler lines from a supporting vendor, they are hydraulic lines and work great.

 

[Mike L.]

Hose clamps won't hold 200psi spike pressures.

 

[NKlamerus]

I'll look into a kit, as well as custom lines. As long as they are high pressure and have the right size ends on them I would hope my shop can make them.

 

[Tano]

The trans cooler on my lb7 leaked in the same spot. Had it pressure tested and ended up being a pin hole in the fins. Mike L had a replacement cooler in stock at the time for a good price and was more than willing to help.

 

[NKlamerus]

Alright so if I replace it all with new lines and pull the old ones out of the body of the tranmsission; do I have to drain the fluid first? Or can I just pull them out, collect what comes off, then prefill the new lines?

 

[Mike L.]

Alright so if I replace it all with new lines and pull the old ones out of the body of the tranmsission; do I have to drain the fluid first? Or can I just pull them out, collect what comes off, then prefill the new lines?

No need to drain anything. The cooler fitting in the trans will continue to leak as you work on it because of constant converter drain back. Make sure your fluid is clean when you pour it back in as the E shift valve will stick. Then the shit starts.

 

[NKlamerus]

No need to drain anything. The cooler fitting in the trans will continue to leak as you work on it because of constant converter drain back. Make sure your fluid is clean when you pour it back in as the E shift valve will stick. Then the shit starts.

Been there done that. Still have that stupid reamer.

How much fluid you think I'll lose?

Also, I'm not sure if it's just my mind getting to me. But it seems like the drip is only really at first, after I run around and get up to temp it slows and almost stops. Any truth or theories behind this?

 

[Mike L.]

Been there done that. Still have that stupid reamer.

How much fluid you think I'll lose?

Also, I'm not sure if it's just my mind getting to me. But it seems like the drip is only really at first, after I run around and get up to temp it slows and almost stops. Any truth or theories behind this?

How much fluid you will lose depends on how much your sealing rings are worn. No telling that. Working with cooler lines can get dirty with pieces of crap falling in the bucket along with dirty hands touching the tips of the line where they hook in. I suggest buying a new bucket from Home Depot and being very carefull not to let crap fall into the bucket. Keep your hand clean at all times if you can. Good luck.

 

[NKlamerus]

Yayyyyyyy.....

I think I'll start at the top and work my way down to the tranny. In theory that should save me a lot of time with open holes in the tranny body dripping fluid.

 

[NKlamerus]

Anyone have GM part numbers for the lines?

I'm at the dealership now getting new Tbar bolts.

And the lady behind the parts desk has no clue which ones go to an allison......even with my vin.....

 

[NKlamerus]

Update, I'm having a local shop build new lines. Also ordered a larger cooler.

Only issue is they won't be done till tomorrow night, as long as I add fluid to compensate for whatever has dripped out is it safe to drive and just keep an eye on temp?

 

[NKlamerus]

How much fluid you will lose depends on how much your sealing rings are worn. No telling that. Working with cooler lines can get dirty with pieces of crap falling in the bucket along with dirty hands touching the tips of the line where they hook in. I suggest buying a new bucket from Home Depot and being very carefull not to let crap fall into the bucket. Keep your hand clean at all times if you can. Good luck.

Hey Mike or anyone else staying up to date;

Do yoy have any links to a diagram or any links to an explanation of why the lines run the way they do? does the fluid run through 2 coolers? I'm trying to picture where the fluid goes after it leaves the trans. And I can't understand why it runs through the large cooler.

 

[NKlamerus]

So i found this. Why does it run through the radiator?

 

[Mike L.]

So i found this. Why does it run through the radiator?

There is no air flow below 30mph so the oil to air cooler can not cool very well. The line must run through the heat exchanger in the radiator to do the initial knock down in heat first before it hands off to the air cooler.

 

[THEFERMANATOR]

There is no air flow below 30mph so the oil to air cooler can not cool very well. The line must run through the heat exchanger in the radiator to do the initial knock down in heat first before it hands off to the air cooler.

Yep, try coming down a steep mountain grade at 35 or less in grade braking for 3 miles with a cool engine. No coolant flow and slow speeds = HOT TRANS!