So, after timing the pump, things were great (but that was a colder day). This weekend, I was running HOT (not really EGT, but Engine/tranny temp).

I pulled over to let it cool off several times, and was putting up a hill at 20MPH because any faster would overheat (I was at the top of the engine temp gauge)

I was pulling a 4 horse trailer with 3 horses in it, and it was ~90 out. Not sure on trailer weight (it's like a 74 straight load, tandem axel) but the horses were probably about 2.4-2.8 K in weight.

I don't have a boost gauge (would low boost cause this?) and I don't have fan shrouds (heard I'll probably have to fab these myself?)

New T STat, but didn't change/flush the fluid when I did that (but it looked pretty good).

Any ideas?

 

slush-o-matic, from what I here. The TC sounds like it is not up to par.

Jon

 

So should I replace the stock with aftermarket, or do I add another one (think I read about under bed ones?) so I have 2 coolers?

 

Problem is the Torque Converter. It creates monster heat when a load is added. What temp are you running on your tranny? With a modest fifth wheel, my temp runs on the edge of insanity going through the mountains. Installing new torque converter as I write this. A fan shroud will help some.

 

When I said TC I meant the Torque Converter

Sorry for the mess up!

Jon

 

Ok...

When it was heating up, Tranny temp was OK until the engine was REALLY hot, then it shot up (210-230). Usually it's 160-180, maybe 200 on a hill.

I haven't looked, does the tranny dump heat right into the regular cooling system, or does it have it's own heat exchanger in front of the radiator? (I don't remember seeing one, only the aftercooler).

I have access to a big brass exchanger that I could put under the bed with an electric fan or 2, if you guys think that would help. It's free, and I was thinking to run the cooling lines from wherever they go now to this exchanger and add some fluid.

I need to pull next weekend, so a TC is out of the question because of time. How much is a better (but not takeasecondmortgageonthehouse better?)

 

Yes, the tranny dumps heat into the cooling system. There's a cylindrical external heat exchanger on the passenger's side of the engine just aft of the turbo sort of down low. It's a little hard to see if you're not looking for it.

Dodge had an option for an auxilary cooler under the bed. It had a fan assist. It was plumped in between the transmission and the heat exchanger. I'm adding this on mine. Most everyone who has one seems to really appreciate it.

 

I was looking, and have access to a huge copper exchanger/block that I'm going to put under my bed with an electric fan (and possibly some plumbing to make it so that driving forces air in as well). Do you normally just unhook the lines from the tranny or from the old exchanger? Does anyone know what size lines/fittings this needs?

If not, I'm climbing under there and cutting them off tonight, so I can go to Napa or Home Depot with the brass exchanger and make sure I get the right fittings.

Should I use steel lines, or is brass ok?

 

You'll want to keep your original heat exchanger. It effectively removes LOTS of heat. If you want to plumb in the aux cooler, do it between the tranny the original heat exchanger. The line out of the transmission comes from the front driver's side of the tranny and crosses under the bellhousing to the heat exchanger. This is the line you'll want to replace/splice/cut or whatever you plan on doing. There's a temp. sensor (for O/D cutout) in this line just right at the transmission. You'll want to be sure to keep this in place. Lines are 1/2" OD. I would think steel would be better than copper/brass. I had some custom hydraulic lines made up at a place just close to my house. That way I didn't have to worry about bending them etc. The fittings are flare fittings. You'll see how it all works when you crawl under there and take a look.

 

Ok,

So I finally crawled under there tonight to get the fitting sizes and estimates for the hoses (having hydro hoses made).

Just to check....it goest tranny (and a "T" type piece witht he electronic sensor for my gauge...I think) to the side of the engine exchanger, out of that to a front coil/condenser unit, back to the tranny. I thought it JUST went to that side engine exchanger...do I have an additional tranny cooler? Do I just need to pressure wash the crap out of that coil up front?

As it is, I run VERY hot, and slow down/stop when tranny temps hit 220 or greater (slow down as in 20-30 MPH on back roads). It won't really cool down unless i have a REALLY long downhill, or shut her down for a while. I'm putting in an under bed cooler that I am making, with a brass coil that is 8x11 with about 4 deep on coils (so it's thick) all surrounded by a thick brass protective case (front and back are open) with ~300 CFM (not sure on that yet, riggings some older fans up to fit that odd sized space) up between the tranny & the engine side block cooler/exchanger. Does that sound rignt?

I'm going to likely put in a new TC this winter during down time, as well as a few other mods (reading the Alchohol mod threads )

 

Yes, all the autos have the little cooler up front as well. Washing the gunk out of that can't hurt. Last fall, I pulled my radiator, thinking it was plugged, and found that the lower half (the half behind the bumper, etc.) was totally plugged externally with bugs, grass seeds, dirt, and what not.

I still think, if you have a freebie cooler, that you'll appreciate having that in your transmission cooling circuit as well. And yes, The fluid come from the front of the transmission, past the T for the sensor, to the side heat exchanger, from the heat exchanger to the front cooler, from the front cooler to the back of the transmission. Add the under-bed unit after the T and before the side heat exchanger.

 

Your torque convertor will cause engine heat build up due to the fact the engine does more work to get the same load moved. I.E. it uses more fuel to move the horses and trailer (than, say, a manual) and in the process, producaes more heat, that gets wasted and transferred to the antifreeze and transmission fluid.

How steep and long are the hills you are talking about? I had a 92 D350 with a stock auto that I towed up to 10K with in the summer of Colo, and had no engine temp issues. Tranny lasted another 100K after that, so I doubt it got real hot.

 

some pretty decent hills, nothing like climbing out of Denver up to the ski resorts, but a lot of up and down.

I'm planning on replacing the TC this winter anyway, but I wanted a cooler for this weekend, as it'll be the longest trip we have taken, and we are taking a full load of horses (horses alone will be 4-5K, not sure how heavy that old trailer is).

Do you think it's something else? I see the water temp gauge go way up, then once it's near the last line, the tranny temp goes way up too...EGT's are pretty good, mostly 10K-12K going up the hills, 6-9 on the downhills.

 

If engine temp is really leading trans temp, you might consider having the radiator rodded. High heat on the engine side eventually runs up the trans temp.

Regards, DBF

 

Where is your temp sensor for the tranny temp located?