Controlling Trans Temps

[JDonahue]

Getting ready to go on my annual Labor Day trip and need some help with keeping my trans temp down. I will be towing my 22ft 5er (that weighs about 6000lbs fully loaded) up a very unimproved dirt road for 18 miles ascending from approximately 6000ft to about 9500ft. The road is very bumpy, and has lots of switchbacks which make getting any speed very impossible. My question is, I will never be able to achieve lock up so how do I keep my trans from overheating? Should I run in 4low so I can get it to shift up to 2nd and lock the converter?? I've gone up this road every Labor Day for the last 20 years but I've never towed a trailer up it and I don't want to overheat the trans. I just serviced it less than 5000mi ago and I do have a gauge. Let me hear your ideas/opinons.



Thanks, Jimmy

 

[klaybus]

4 wheel low works for me when necessary.



Clay

 

[JJPage]

If you add 1oz. of lube guard(red bottle@NAPA) per quart of trans. fluid, it should help with the heat. It is about $10. 00 for a 10oz. bottle.



I'm not a snake oil salesman, Bill @ DTT actually recommended that I use this product and I intend to tomorrow when I service my own transmission

 

[Bertram65]

I recently did some towing for about 10 miles at less than 20mph towing my 10k 5th wheel, my trans did not read above 180 degrees. It heated up to about 190 when towing at higher speeds between 30 and 45 with high engine speeds, 2700 - 3000 rpm in 2nd with the TC locked, same when coming out of Lake Placid in NY and using what little grade braking the diesel can provide, my probe is in the pan now though I have seen the same temps with it in one of the test ports. I was towing in VT in a very hilly area, there were signs actually saying it was not reconmended for trucks with trailers.

 

[CChinman]

03 towing 6K

I will be towing a 20ft boat and trailer from SoCal to AZ. As I drive around town with it hooked up the only temp gauge I have is on my dash cluster and it indicates just about 12 o'clock. Unloaded it runs a bit cooler but I am interested if I need to do anything inparticular while driving through the mountains up to about 6000' in 90-100 degree temps. It is all freeway.



Thanks



03, 3500 4X4 QC, 3. 73, BFG 315s, SRW LB

 

[JAshpaugh]

I just got back from taking my 28' Weekend Warrior 5'er over the Grapevine from LA to Lake San Antonio. It weighs 10K +. I drove most of the trip in O/D but on the hills had to go to 3rd and on the Grapevine to 2nd. While in 2nd just held it at 2000 rpm about 40 mph. transmission never got over 190 the entire trip. However while in O/D and climbing slight hills the EGT went to 1100 a few times so I went to down to 3rd and the dropped to 900-1000. The outside temp was about 90-95. Oh yeah, I also run Amsoil ATF so than might help...

 

[groser]

Your distance and rise equals a 4% grade on average. That in itself is moderately steep over that distance. If it's 100 degrees outside you will get some transmission warming but 6,000 lbs is not terribly heavy. I tow 13,000 lbs up the Eisenhower Tunnel on I-70 and on hot days I can't make it (+95 degrees. ) Some times engine temps get me, sometime transmission temps. Depends how slow I have to go. At that weight if something slows me down I can't regain speed because rise is to steep on this stretch of highway. I have a modified transmission but my stock Cummins is weak for 13,000 lbs in my opinion. I would be more worried about the 20 MPH average because most trannys get warmer at such low speeds. My experience, rather than spend a lot of money on upgrades; pull it at night when it's cooler and see what happens. If you have problem adding additional transmission cooler is not that expensive. I also run Amsoil ATF but that doesn't make it run cooler, it just lets the ATF get hotter than standard ATF before it chemically breaks down. Sort of an insurance policy. The plastic parts and seals in your transmission still melt at same temp no matter what ATF you use.

There is one major difference between your 2004 model and mine, you have a much better transmission cooling sytem for steep grades. If I understand it correctly the 2004 DOES NOT use engine coolant as a primary transmission temp cooler. The 2001 does, so when pulling steep grades if the engine coolant begins to get hot so does the transmission fluid, the tiny transmission trim cooler in front of the radiator is way to small to cope with hot radiator fluid on the 2001 model.

On mine what I've noticed is my transmission temps will get to 160 degrees (in pan) when it's about 75 degrees ambient and I'm pulling moderately hard(the Eisenhower is much worse than moderate!). For every 10 degree rise in ambient above 75 degrees I get a 10 degree rise in transmission temp. So at 100 degrees outside I expect to get about 185 degrees transmission temp if pulling; and that's exactly what I get. In other words at 75 degrees ambient the maximum cooling I'm getting results in 160 degrees transmission temp. Any rise in ambient after that results in same rise in transmission temp. Also I pull in lockup at all times, even at 60 MPH or in 2nd at 20 MPH because that's how my ATS Co-pilot is set up and this makes for cooler transmission temps.

 

[bmoeller]

The 2001 does, so when pulling steep grades if the engine coolant begins to get hot so does the transmission fluid, the tiny transmission trim cooler in front of the radiator is way to small to cope with hot radiator fluid on the 2001 model.

I would suggest a 180* T-stat, in place of the stock 190*. Rarely goes over 190*. Haven't had the engine fan kick on since the t-stat swap. A modded valvebdy will help considerably. They flow more oil, and with higher line pressures, it reduced the chance of transmission slippage, or with the T/C lock-up clutch. My Goerend transmission runs MUCH cooler than the stock POS.



EGTs are the only thing that slow me down. Hoping the new HTT will change that.

 

[groser]

Bmoeller, I already have a 180* T-stat and ATS TC/valvebody with lockup. These resulted in lower engine and transmission temps but when pulling steep grades at +6,000 ft in +90 degree weather it only delays the onset of higher temps. Eventually if pull is long enough and steep enough, say +10 miles, I will overheat. The diesel may not lose much power due to altitude but beleive me the thinner air results in weak cooling. I can pull steep grades all day long below 5,000 ft with no problems. I need more power and lower EGTs as EGT is also my limiting factor at this point. Right now I just plan my steep pulls and if worried I pull at 0600 hours. Most steep pulls are only 45 minutes long so it's no big deal.

 

[JDonahue]

When I've towed over Eisenhower this year my temps have never gotten above 160 in the pan. However on the 4th of July weekend we got out of town late and got stuck in stop and go traffic from Genesee to Georgetown and I never really got out of 1st gear and my trans temp got up to 190. I don't really have any problem with 190 I just don't want to get going half way up the mountain (with really no place to pull off) and have a problem. Sounds like I should probably just plan on leaving early in the morning before the outside temp gets too high and if I have a problem I'll just have to pick a place to shut it down for a while. Thanks for all the replies and ideas!



Jimmy

 

[klaybus]

When I've towed over Eisenhower this year my temps have never gotten above 160 in the pan. However on the 4th of July weekend we got out of town late and got stuck in stop and go traffic from Genesee to Georgetown and I never really got out of 1st gear and my trans temp got up to 190. I don't really have any problem with 190 I just don't want to get going half way up the mountain (with really no place to pull off) and have a problem. Sounds like I should probably just plan on leaving early in the morning before the outside temp gets too high and if I have a problem I'll just have to pick a place to shut it down for a while. Thanks for all the replies and ideas!



Jimmy

Just remember... Pan temps are not the best location to check your trans temperature from. For the MOST accurate location your trans temperature probe would need to be installed in the line going to the heat exchanger. Then, you truly know what kind of temperatures your dealing with..... FWIW.



I can hit 190* in commuter traffic empty, easily. If I remember correctly theres like a 40*-50* difference between the pan & the heat exchanger line.....



Clay

 

[cwsoules]

Pulling a 10. 4K 5er in bumper to bumper traffic in El Paso a couple of years ago my transmission temp before the cooler would approach 210. When at stop I'd shift to neutral and rev the engine and could get the transmission down to 200 if we were stopped long enough. Two years ago DTT added a second transmission cooler as a chin mount below the radiator. I've not had a problem since then.

 

[bmoeller]

Hmmmmm. Are the radiator fins clean and straight? Is the radiator clean inside, without any deposits? Fan clutch kicking on like it supposed too?



I had to replace my radiator last fall after I hit a deer. Runs a bit cooler now. Even with a stock 3 row.



May need to go with an aftermarket trans cooler with a fan on it, for additional cooling. Running slow on long steep grades, you don't have as much "ram air", if you will, to keep the temps in check.