New to this site, not new to dodge CTDs...

Coming from an '08 6.7L 2500 I sold simply because I wasn't happy with having a car payment and there was so much electronics on that truck... i switched to a '93 D250 with an A518? (I think) On a regular basis, I tow my rock crawler. (93 XJ I attached below) It's not anything special, but she is heavy. Along with the cage, it has 1 ton axles, and I cut out the floor and replaced with 3/8" plate steel.

I tried to attach a pic of the truck and trailer but for some reason it says failure to upload.

This past weekend was my 2nd time towing with this truck, 1st time with the gauges installed. I turned up the pump just a turn or two because I had noone there to help me in case of a runaway. I am having quite the problem with trans temps. On a couple of occasions, I saw temps close to 270!! Running down the highway, 55-60 I am seeing a steady 210-220 temps. From stoplights, or in town temps climb rapidly.

Is there anything I can do to help? I bought a large cooler the other day, and am installing that in between the intercooler and radiator. Hopefully this will help somewhat on the temps.

I just replaced the fluid and filter the other day. Being that its a non-lockup it takes me a bit to get used to. I really hate it not being locked, makes me feel nervous that somethings wrong. I cant help but think that temps wouldn't be an issue if i had a lockup trans.

The truck has 220k and I'm pretty sure the trans has never been gone through. Possibly there might be some other issues internally. When I changed the fluid, there was alot of black buildup on the pan magnet. Also, there were flakes of silver in the pan. (kind of looked like the gold pan shots on those TV shows) What steps should I take? I hope that towing this crawler will not be the death of the trans, but if it is what can I do to make it better. I am not a racer. Just want to bump the power a little more to get me slightly closer to the power of the 6.7.

 

Maybe from the photobucket it will work....

 

Hey now. Welcome to our forums.

I don't have any experience with the newer trucks, but as far as the earlier 12v, they had pretty-much the same trans cooling plumbing.

- The hot transmission fluid leaves the trans from the tube closest to the front of the truck.
- From there, it goes to the passenger's side of the truck and into a fluid-to-fluid heat exchanger. Engine coolant is used to heat/cool the transmission fluid. That is to say, when the transmission fluid is below it's nominal operating temp (cold), the engine coolant helps bring the trans fluid temp up. Certainly, when the transmission fluid is hotter than the engine coolant, the engine coolant cools the trans fluid. Know that a fluid-to-fluid heat exchanger is substantially more efficient than an fluid-to-air heat exchanger of comparable footprint.
It is my opinion those who think: "Get rid of that heat exchanger, it only adds heat" . . .. are in error.

Anyhoot,

- The now cooled/warmed transfluid then goes back the the driver's side of the engine and toward the front of the truck. On the driver's side/top of the radiator, you'll find a bar & plate type of fluid-to-air heat exchanger (a little radiator). It helps further cool the trans fluid when you're working things.
* Isn't that counter to the first heat exchanger adding heat when needed? Yes it is. That's why you'll find what appears to be a small "H" shaped assembly in the hoses as they go to and from the front cooler. It will be located in the hoses near the driver's side of the radiator support.
That H-pipe helps cypher whether the trans fluid actually goes through that front cooler. It apparently works in conjunction with the front cooler by way of the different trans fluid viscosity one would see with cold, cool, warm, and hot trans fluid. (In cold weather, the front cooler will cool the fluid to the point it would get thicker, than the same warm fluid. As such, the trans fluid flowing from the trans is gonna take the route of least resistance, and bypass the front cooler via the H-pipe.

Clear as mud?

- From there, the trans fluid flows back to the transmission via the tube toward the rear of the trans . . . . . unless you've got the factory optional auxiliary cooler. It has the fluid coming back from the tront cooler, and has it flow through a second, fan assisted fluid-to-air heat exchanger under the truck, driver's side, between the cab and bed.
- Then it flows back to the trans.


I would first make sure that fluid-to-fluid heat exchanger is in fact still connected. It's located under the exhaust manifold and looks like a tank about 5" in diameter, and about 12" or so long.

I would then make sure that front cooler is still connected and not actually hacked with a cheap add-on cooler (tube & fin).

I would also ensure the general engine coolant system is in good operating condition. That includes ensuring your radiator's fan clutch is operating correctly and cycling ON when needed. Be sure the radiator's clean both internally and well as externally. Mess like that.

How heavy is the load you're pulling?

Finally, Is this occurring primarily when in overdrive?


You may have to slow down some and back out of over-drive.

Hope this helps more than confuses.

 

When properly installed, the fluid goes through the underbed mounted cooler before it goes into the heat exchanger, then through the front mounted cooler.

 

I only have the exchanger on the side of the block, and then a small scabbed in cooler mounted horizontally under the radiator. (thanks to the PO)

Does anyone know the size of the factory metal lines? I want to buy the proper cooler today online so I can get it installed. I purchased one the other day from the auto parts, but the line is too small. Almost like 3/8 line. The factory line looks more like a 9/16 or so?

What I want to do is keep the factory steel lines and mount a new cooler in front of the radiator (or under the bed with a fan, I dont care) What size cooler inputs do I need to get the hose to mate up with the factory lines?

Thanks!

 

Factory lines are 1/2". IIRC that's OD.

 

The cooler I bought has 3/8 line inputs on it. It however is not the tube and fin style. Seems to have a tube up both sides, and then multiple pass throughs. Like this one


http://www.autozone.com/autozone/acc...er=238922_0_0_

Am I hurting anything by necking down to 3/8 line? Should I buy one that has the proper inputs? Any suggestions?

or can I just do this:

http://www.jegs.com/i/JEGS-Performan...ductId=1423174

 

Anything you can do to get fast moving cool air near the trans fluid will help, such as that fin tube coil in front of the radiator and condenser.

My truck has the whole system as described by BC847. Tranny guy wimpered like a hungry pup about how much work it was to flush the whole system out when my tranny ate a ball bearing in the OD. About the time I would put the radiator cap in orbit, my tranny temp might hit 175. Usually runs 125 on the road, and about 150 in town, shifting a lot, pulling the train. (recreation double)

 

Mine runs 200+ all time and about 230 in the summer coming from the hot line out of the converter. I always thought this was kinda high but it works.

 

Well I got the proper fittings and plumbed in the cooler that I had placed in front of the radiator. We shall see if that keeps the temps a little more in check. I am in a dilemma right now on what to do. I don't know if I should just plan on a rebuild of the 518, or if I should spend the money on a 47rh. (so I can have lockup) Anyone throw a guess out for the cost of a rebuild + converter for the 518? I might try to rebuild it on my own... not sure. I would probably be in around 1200-1500 for a 47rh swap.

 

Is this in pan temps, or hot line temps? I am measuring fluid temps right where the factory sensor was originally at. If your talking "after cooler" temps then that explains the difference

 

Luv my underbed factory cooler. With HI FLOW fluid and FAN.

That rascal works it's tail off. I tow 30k GCVW in steep mtns. but... I need a MANUAL tranny with LOTS of gears... next time. Thank goodness for low range, or I would be toast, as the goofy factory High RPM TC makes heat REAL well.

 

I have a temp sensor in the hot line as well and my temp mirror yours, i have a 16x16 derail with fan and i still get pretty warm, if you will kick it out od O/D on the uphill climbs it will be OK, i believe if you had your sensor in the pan it would be in the 180* range and that is an exceptable temp.

If you will shift it manualy through the gears and let it build some more RPM's it will shift alittle firmer and slip less thus not building as much heat.

nice truck by the way, this is what i haul for the long hauls, and on ocation i pull some other stuff on a 25ft goosneck.













i know i know i'm a picture *****...

Dar

 

love that truck...and love your xj crawler, your best place for the temp sender is the outlet "hot" line, ive seen some with multiple senders in case/pan, i guess if you dont like the high reading, move to another sender and get peace of mind. my trans guy swears by the bar and plate cooler, biggest is best, and your thoughts of locking converter will bring big results to performance, especially with power greed in upping the ve's output, the converter is a pricey necessary upgrade that comes with the early transmissions. your trailer looks just like my az tex diamondback flatbed, im guessing you could build a nice towing trans with a upgrade converter for under 3 grand, you should get some more regional accurate prices from more posters that have done it.

 

Here is what I have found,

I have the Dealer Installed Super Duty Transmission Oil Cooler installed on my truck and after 20 years of constant use it started to develop a slight leak.

In case you did not know this was an option you could have your dealer install that would increase the maximum trailer tow rating from 12,000 to 14,000 pounds.

Here I removed the cooler from the truck leaving the housing and blower still mounted I was trying to find where it was leaking from.



This is what I had found to replace it with; it was an exact replacement except for the bung for the thermostatic switch.

Tru-Cool Engine Oil Cooler



11" x 11" x 1 1/2"; 29,200 BTU



With 1/2 NPT Fittings.



After removing the blower housing from the bottom of the truck it was photographed, dismantled and thoroughly cleaned, after it was clean I applied a quick coat of paint.
Here the included baffles are installed to help seal the connection between the cooler and the blower housing.

I am going to supplement these using a dense foam gasket to make it more air tight and a better airflow.



Here I am about to installed the ½” NPT to 1/2” hose barb fittings.



The cooler actually fastened from the inside using ¼-20 hardware.

The entire cooler mounts up under the bed and is secured using 4 rubber expansion nuts.



Now the motor assembly is mounted on top of the unit and secured.

This fan motor rolls on ball bearings.



The fan blade is installed and secured using a clip.




I have 2 Pro-Comp electric fans on the front of my truck to help with my air conditioning and when trying to compare them, this factory fan unit will low then away when combined with its 29,200 BTU capacity this makes a very powerful external cooling package, in fact since my transmission has been rebuilt, the under bed cooler has been all that has been cooling my transmission until I get my cooler installation completed.

If you have one of these, hang on to it, (or give it to me) if you find a leaking one, buy it and repair it

Here is the routing diagram for the transmission hydraulics.



BTW although the transmission hard lines and connecting hoses are 1/2" the fittings where they connect into the transmission case at least on my A-727 are only 3/8"

I have all of the documentation on this cooler if you want to see it.

Jim