Good evening, all. This is my first time posting on here, so please be patient with any mistakes I might make.

So, I've owned my '90 D250 Cummins for 26 years. Bought it with 70,000 miles on it, and it now has roughly 420,000 on it. Best dang vehicle I have ever owned, bar none. I recently added a stablemate in the form of an '89 D350 dually Cummins with under 84,000 miles on it (I know it's only a 5-digit odometer, but the truck presents as a low milage vehicle, thus supporting the claim). Anyway, it turns out that the 727 has the "Strawberry Milkshake of Death" running through its veins. Wonderful. Therefore, I am desperately seeking an '89-'91 (non-intercooled) heat exchanger. I have only been able to locate three on fleeBay, all showing as very crusty east coast units. That is not an avenue I care to go down at this particular moment in time. I am hoping that one of you might have one kicking around that you'd be willing to sell, or know of a viable resource for one. I plan on hauling with this rig, and after reading many debates on the subject, I've decided that I'd rather replace the unit than go with a "delete". Can anyone help me out?
Much obliged.
Mark

 

Transmission Oil Cooler Dodge Ram / Cummins replaces 3926670, 4762090, 4746216 (19868) (americancoolingsolutions.com)

 

Thank you so much for that, Sheep Herder. I do have a question, though. It shows as being compatible with the '90-'93 W250 and W350. Now, I can't imagine what difference there would be between a 4wd and 2wd (W-series and D-series), but never having owned a W-series Dodge Cummins, I can honestly say that I have nothing to reference. My concern would be two things: 1)They didn't reference an '89 in the years of compatibility, and 2)They made a point of listing the W-series, but not the D-series. As far as I can tell, it looks like the one on my truck(s). Any opinion or comments on my concerns? I would absolutely love for this to be just the ticket. And even if it isn't, I do greatly appreciate you taking the time to look into my initial request.

 

I think they are all the same for '89- '98, but I really don't know for sure.

It works great for my 91.5 W350.

It looks the same as my "95, but I know that's not much help.

 

Think I'll give them a holler tomorrow, and see what criteria they used for determining compatibility. I've been searching for about a week, and had seen that very same part along the way, but it was listed as being for the 4BT, so I immediately dismissed it. Well, after going back and revisiting that listing, it says further down in the ad that it was also compatible with the '90-'93 6BT. Who'd of thunk it?

Thank you again, my friend. I'll look into this further, and let you know what I find. So stoked about this!

 

I think I may have stumbled upon a slight difference. The new one we've been discussing has oil ports that are 3/8" NPT and 1/2" NPT, whereas the earliest ones appear to be both 3/8" NPT. If that's the only difference, then I would think I could utilize a fitting that reduces from 1/2" down to 3/8". Any thoughts on this?

 

Yes, I forgot about the one different size port. Like you said, I just bought a brass adapter, no problem.

 

There are advantages and disadvantages to a tank type heat exchanger. The disadvantage is the problem you have, antifreeze in your transmission. The advantage is it heats your transmission fluid went is COLD outside. Up here in Alaska that becomes a big advantage. If I lived in warmer climates, I would ditch the tank for a radiator with a fan.

 

Hey, cougar. Appreciate the input. The reason you stated about the unit actually being beneficial in colder climates is also one of the reasons I would like to keep one on my truck. The wife and I are considering a move within the next couple of years, and there's a good possibility that where we end up might very well have colder winters.

 

Excellent, Sheep Herder. I like hearing news like that. Btw, I'm curious about something. I've read that the coolant contamination in the transmission fluid will break down the glue that holds the friction material to the clutch rings. Did you experience any damage to the clutches and/or swelling of the seals, thus requiring a rebuild? I'm assuming, of course, that you replaced your HE with a new unit due to it failing in the same manner that mine has.

 

Hey, Sheep Herder...just wanted to thank you again for the link. I spoke with someone at ACS, and ultimately my local Dodge dealership, all in an effort to confirm the compatibility of the replacement part. Just ordered it moments ago, and couldn't be happier that someone on this forum was so quick to assist me in resolving this issue. Kudos to you, my friend.

These are the photos from the gentleman that I bought the truck from...

 

Yes that is what happened to the truck. Strawberry milkshake. I actually bought the truck that way, with the tranny non operational.

When I got into it, all the clutch and steels were fried. It had gotten real toasty. It was a real bear to get some of the hard parts separated.

I'm glad I could help you out.

 

Seller said mine was driven about 1,000 miles that way. Tranny shifts fine, for the time being, but I haven't driven it beyond bringing it home. Bought a book on rebuilding the 727/904. Might give it a shot. I've owned over 320 vehicles in my life, and typically do most of my own work. However, a transmission rebuild is not one of the things I've tackled in the past. I typically watch so many videos on my chosen project that by the time I get in there, I feel like I've already done it before. Still, I usually know my limitations, and proceed with caution.

 

I would get the ATSG manual for the A518/A618, and a FSM.

You probably have more mechanical skills then me. I've rebuilt about 10 of them, its really not too tough.

You might check these videos for a basic how to.
46RE Videos (transmissionbench.com)

 

I have the FSM on my '90, which I'm thinking would suffice. I'm guessing that the ATSG manual for the A518/A618 (though I have the 727 in my trucks) implies that those transmissions are just variants of the 727 (a 727 with overdrive, I assume?). I've never owned a vehicle with either of those transmissions, so I'm unfamiliar with them. As for technical skills, nah...Jack of all trades, master of none. I just like to tinker.