Trans Pre-cooler lines...

[Hatley Rocket]

I bought my ‘95 12V 47RH last year. I haven’t driven it much since then, unfortunately. The first thing I did was change the oil, oil filter and fuel filter. Just after the oil change, I noticed coolant leaking. One of the two black coolant pipes that wraps around the oil filter had rusted through and I disturbed it when removing/reinstalling the oil filter. So I replaced those lines, and that was a royal pain. I had to remove that cooler along with the transmission lines in order to get those steel coolant lines installed. I got it all back together and then a few drives later I lost overdrive. I diddled with the tps, that didn’t help. I also noticed that transmission fluid is leaking. I don’t know if the loss of 4th gear is related to the fluid leak or not. I’m thinking the fluid leak is from the lines being disturbed when removing and replacing the cooler. I’d like to replace those lines, but I can’t seem to find them online anywhere. Does anyone have part numbers or links to fiche drawings of this system? Any advice on getting 4th gear back? I’m assuming that whilst I’m leaking trans fluid like a sieve, pursuing overdrive is futile.

 

[DavidC]

Check here
https://www.rockauto.com/en/catalog...,transmission-automatic,oil+cooler+line,10343

 

[mwilson]

Couple of thoughts...

How much transmission fluid did you lose when removing the cooler??? When you check the fluid level of the transmission are you doing do in Neutral??

 

[Hatley Rocket]

David,

Thanks for the link. I can see the one pictured from the link with the flexible portion where it connects to the cooler, but it doesn’t look like the return line has one. Maybe I’m looking at it wrong?

 

[Hatley Rocket]

Couple of thoughts...

How much transmission fluid did you lose when removing the cooler??? When you check the fluid level of the transmission are you doing do in Neutral??

I don’t think I lost more than a quart or so. At first I was checking the level in park, until I was corrected on another forum. I “had” it up too full, but that claim is dubious as I’m losing fluid also.

 

[mwilson]

There is also a switch involved that screws into one of the lines underneath, until the trans fluid gets to a certain temp it will not allow the overdrive shift as I recall...might want to see if that came unplugged or got damaged...

Really cold mornings you have to drive a ways before you get the overdrive shift....

 

[mwilson]

That external temp switch was on '94 and '95 trucks, later models had it inside the transmission.....

 

[Hatley Rocket]

There is also a switch involved that screws into one of the lines underneath, until the trans fluid gets to a certain temp it will not allow the overdrive shift as I recall...might want to see if that came unplugged or got damaged...

Really cold mornings you have to drive a ways before you get the overdrive shift....

I heard about a wire that supposedly needs a resistor added to help convince the trans that it’s warm enough. The last time I had OD, I left my home, drove about one mile to the highway (in February) and it didn’t want to shift into OD straight away as it had in the past. It took a couple miles and then it shifted into OD. I got to my destination 15 minutes later, and shut off the truck. Came back about 15 minutes later and made the drive home. On the drive home, it never got into OD. I haven’t had it since.

 

[DavidC]

David,

Thanks for the link. I can see the one pictured from the link with the flexible portion where it connects to the cooler, but it doesn’t look like the return line has one. Maybe I’m looking at it wrong?

You could try calling them about the lines, hopefully tech support can help and make sure you get the correct parts if they have them

 

[Timd32]

David,

Thanks for the link. I can see the one pictured from the link with the flexible portion here it connects to the cooler, but it doesn’t look like the return line has one. Maybe I’m looking at it wrong?

My 96 One has the flex, one does not. They will leak pretty good after you disturb them, I ordered new ones a while back, also a whole new cooler mine was shot, one line came in pretty mangled they are pretty hard items to ship. I had to reuse my old one with the flex hose.

After reassembly my leaked at that same connection too bad to drive I dried them off really well, tightened them up, then ran it in Neutral for a bit, shut it down and check for fluid leaking down the tubing.

My new cooler the female threads would bind with new fittings, so I looked a bunch of places and ordered up a few fittings never found the correct set, so had to reuse the old brass fitting.

I hated to use the old line and hose but its been 3 years and no leaks. I could only really get this from underneath once it was all back together.

Took me a few tries to get it to stop leaking.

While I doubt it but could be you unscrewed the fitting from that cooler as well. It's in a really rough spot.

 

[Hatley Rocket]

That’s about what mine looked like! Where did you find the replacement? When I get the new lines I may just pull it out and make sure none of the adapters are loose too. Is that the way to access that area, removing the turbo? Looks like you had tons of room that way!

 

[Timd32]

I was doing some extensive rework to my truck, I had the battery boxes out, the alternator, and the turbo.

But I was doing all sorts of stuff on mine at that time.

It sure made it easier to pull out. But even with that access either I forgot to tighten them up, or using the old lines and the sort it leaked really bad when I finally got it all back together. Took me a try or two to get them reseated properly.

I had a quote from my Cummins dealer in excess of $2k for that cooler for some reason its crazy expensive from Cummins.

American Cooling Solutions

Transmission oil cooler Dodge Ram / Cummins replaces 3926670 4762090 4746216

http://www.americancoolingsolutions...ram-cummins-replaces-3926670-4762090-4746216/