Just got to tow with my X for the first time. Hensley Arrow, Helwig and RS-9000x shocks made it a reasonable tow. But, my tranny temps were surprising.

Air temp was in the low to mid 60's, light rain, in the gently rolling hills of western Wisconsin - no single grade was longer than a couple of miles, or higher than serveral hundred feet and speeds of 50 to 60 MPH - kind of slow, but it was my first tow.

Tranny temps went up to 180-185! They hung pretty high, even on the down slopes. I've got 3.73's and slightly oversized tires (285's) so it did down shift on some of the grades - I was towing in OD. Temps seemed pretty high to me, given the low outside temps. Temp data was measured via the PCM and AutoTap.

Any thoughts? Time to get the aux cooler installed for the late summer drive to Florida?

 

I have 3.73s, V-10 and stock tires. I tow a 6500# travel trailer and never have seen the factory tranny temp gauge move (once it has reached operating temp). I wonder if towing in OD with oversized tires may have pushed the tranny temps up? Maybe consider keeping it out of OD? Then maybe getting 4.30 rear ends (with appropriate front end gears too) if you're going to run oversized tires. The tranny cooler on the X's are already huge...can't imagine that being the limfac.

 

I installed an AutoMeter trans temp guage to monitor my temps and found they were getting up to 220 on long runs in the mountains with a 10K trailer behind. I added an additional trans cooler in front of the radiator and dropped the temps 30 degrees. 190 degree trans temps are completely fine. You'll just want to pay attention to changing your trans fluid more frequently as any kind of towing is considered severe duty.

 

The trans is designed to run at about 180F. You're wasting money trying to get it cooler while towing. There's no need.

 

Got any documentation on this?

It certainly runs cooler than that without towing. It seems the valve that cuts off flow to the cooler is set for a temp of more like 160 or so...

 

There is no temperature valve on the 4R100. There is a pressure relief valve that is designed to open if the cooler is plugged. There is always flow to the coolers.

I don't have any documentation to prove that 180F is where it should run.

If you want to run it cooler buy a trans cooler from a 6.0L truck. It's a direct bolt in, but you'll need to adapt the cooler lines to 1/2" that the 6.0L cooler uses. It's huge, and will reduce your temps.

 

I have a 7.3L '01 and it doesn't seem to have a tranny temp gauge. Just how difficult is it to install one or have it done.. I am regularly pulling 9000# over mountain passes all over the western US and am planning a trip to Ca over the Siskiyous and in and out of Tahoe this summer in high temps . Heck,even getting the TT into the backyard is at least a 12% grade of about 75 yards at very low speeds and since part of it's gravel,4 wheel drive..

I have a tranny temp gauge on the school bus and even with a full load of football players on the freeway the temp never gets too high..

 

No temp valve!?!? Doesn't that make the tranny run way too cold in the winter? I'm in Northwestern Wisconsin, and temps of 40 below are not uncommon. Even with a cover over the radiator area won't things get kinda cold in the tranny?

Good info on the 6.0L PSD cooler - I like bolt on...

 

[QUOTE=bigdog55]I have a 7.3L '01 and it doesn't seem to have a tranny temp gauge. Just how difficult is it to install one or have it done..

Bigdog, I have a similar rig... just add 4 wheel drive. I added an aftermarket trans-pan (mine is Mag-Hytec but I am sure that there are many) and it has a provision for a temp probe so that you can add a gauge. I had my mechanic add an "A" post gauge stack. You might really want to consider doing the same if you are going to be in the mountains dragging 9000#. For me I have an EGT, Turbo Boost and Trans temp.

A little more info. Today is the first day I drove the eX with the new gauge stack with a trailer. I had gravel loaded into the trailer and the scale at the yard read 18,030#. I pulled the load up some pretty serious grades in the mountains around Frazier Park. I think that I gained about 1500' in altitude for this pull. Trans temp only got up to 190 the OAT was in the low 70's. I will really test it out later this month when I pull max. gross again up the Baker grade and then the St. George climb on the way to SLC up the 15. I am anticipating that the OAT is going to be in the hi 90's or low 100's.

Hope this helped, G.
'01 PSD 4X4 Limited

 

Let us know how the temps read on those trips. I'm very familiar with that run north of St. George and it will be a good guage as to what temp the trans will max out.

 

Normal Operating Temperature.

Is 175*.
This is an article to prove my information.
The use of auxilliary coolers with an electric fan is the best.
In extreme cold weather it is advisable to cover the radiator or install a bypass system.
Fluid will gel at low temperatures and hiway speeds which results in no lubrication and a complete melt down.
I have used old a/c condensors, clean it out and bolt it in.


http://www.roscommonequipmentcenter....notes/nn15.pdf

 

[QUOTE=SRB X25 Maybe consider keeping it out of OD? Then maybe getting 4.30 rear ends (with appropriate front end gears too) .[/QUOTE]

A transmission that is not in "lockup" will run hotter than one that is locked up. Driving out of overdrive still allows the converter to slip, and creates heat. Your suggestion of deeper gears is the way to go, especially if towing with larger tires is going to be the norm. This will keep the engine at a comfortable rpm range for towing, and allow the trans to run in OD, or lockup, and help keep temps down. As far as temps around 180 deg, that should not be a very bad thing. Keep them away from 300*, that is when things get crazy hot, and fluid starts coming out.

 

Definitely agree with you on the tranny temps going up when the torque converter is not locked up, but the torque converter DOES lockup when not in OD. Besides the owners manual says to turn the OD off when

"...driving conditions cause excessive shifting from O/D to other gears. Examples: city traffic, hilly terrain, heavy loads, trailer towing and when engine braking is required."

I would turn the OD off first to see if this helps...it doesn't cost any $$$ to try it.

 

For years I wondered what that "extra" gear was after shifting from one gear to another. When shifting into OD you can watch the RPMs drop and the drop a little more. When disabling OD, you see the rpms climb and then drop a little a few seconds later. I'm assuming that's when the converter locks and the slipping stops. It's most noticable in OD but you can also feel and watch the RPMs change when you turn off OD. I don't know if the same thing happens in 2nd gear. Haven't noticed that.

 

I was asked to report in on my trip from Los Angeles to Salt Lake City. I take the I-15. Here it is. So that you all have a reference point I will start out with what I have and the changes that I have made to my EX. '01 PSD 4X4 Limited, AFE stage 2 intake, 4" turbo back exhaust, Mag-Hytec transmission & differential covers, custom program (chipped), new compressor wheel, engine brake, stock size tires and an otherwise stock 4R100 (for now). I pulled a trailer for those of you that didn't know it, and since I was giving a report I pulled onto certified scales. My full of fuel certified weight was 17,600 lbs with the driver.

Baker Grade: OAT (Outside Air Temperature) 103 in Baker and 90 at the top of the hill. In Baker my trans temp was 190. I locked out overdrive. I was going about 55 up the grade. There may have been a slight tail wind I am not sure. I was probably about 140 or so pounds lighter due to spent fuel. I kept the EGT at 900 - 1000. Boost was about 12# and steady as I recall (not too sure here). I had the A/C on but the engine temp never budged from its Normal Operating Temperature (Is it really working?) The trans temp slowly climbed but never went above 208.

St George to Cedar City: St George OAT 76. Cedar City OAT 74. Topped off the fuel tank in St George (Flying J- best fuel price between and including LA/SLC). I kept the same driving parameters as I had on the Baker Grade except for the A/C. I think that the boost was only about 10# though but everything else was the same. The trans only got up to 195 at the highest.

I make this trip each month, but this is the first trip with the mods and gauges. One thing that I did notice was, on the climbs the trans seemed to run coolest (in relative terms) if I was running the engine at about 2200 rpm. Not so great for fuel economy though.

I hope that this was helpful to someone out there. If you have any other questions drop me a line I'll try to fill in the blanks. I go back to LA later this week. It should be pretty warm when I go back especially in the State Line to Baker run (back side of the Baker Grade). It shouldn't be too hard though because my trailer will be empty.

Happy Trails, G