I just got back from vaca to Silverton, CO from Tulsa. My '01 PS hauls two atv's on a rack in the bed and pulls a 31'travel trailer, along with all our stuff. I pretty heafty load. I installed a Tru-Cool trans cooler before the trip hoping to avoid tranny heat problems. The tranny did run cooler and with no problems even in 100 degree weather max temp of 180....except the last 20 miles into Silverton from Durango. This section has 2 passes to pull with long steep sections. Tranny got hot and had to pull over twice. I don't know what else to do....do I have a torque converter problem?

 

How hot did it get? Where is your temp sender located? It's impossible to say if you have any problem without knowing how hot it was.

That is a severe trip. I've towed many trailers on that route.

 

Yes, probably one of the steepest climbs around. Like Mark said, how hot was hot?

 

sounds like a fluid change is in order definitely......but the temps you reached could help to know if damage was done

 

If you were going too slow, or if you were in 2nd gear, the TC wouldn't have been locked. That would generate the excess heat. Nothing wrong with the TC; the heat is normal. Also, the low speed cuts down the air flow through the radiator, reducing the cooling.

When you installed the tru-cool, is it in series with the existing coolers? I hope you didn't replace the original cooler with the tru-cool. If you did, reinstall it and plumb them in series.

Finally, are you sure the automatic radiator fan is working? You can hear it kick in and roar; if not, replace it - that would make a big difference at low speed.

You can install a manual TC lockup circuit. Its pretty simple. Check around on this site for instructions, or buy a kit from one of the sponsors. That would eliminate the heating caused by the normal TC slippage at low speed. In addition, you will get some extra retarding going downhill as a bonus.

Good Luck
Warren

 

What speed were you running?
Being that the truck in question is an 01, you probably have a PMT2 box code. This code will allow a 2nd or 3rd gear torque converter lockup under the right circumstances. If these conditions are not met, the TC remains unlocked. Since I am at work, I don't have access to my tuning database, but IIRC, the TC will lock in 2nd at 22-25 MPH just less than full throttle. When the transmission shifts to 3rd, the TC remains locked as long as the accelerator pedal is not released during the shift. Otherwise, the TC will lock at 35 MPH in 3rd with little accelerator input.

If the TC was not locked for some reason, the tranny temps will get very hot....very quickly. I am not a huge advocate of the "TC lockup mod", but in some cases it works very well when used as needed. I usually use it when pulling my wife's horse trailer up steep gravel roads at less than 15 MPH in first gear. This way I don't have to drive 22+ MPH around sharp corners on a rough gravel road just to keep my transmission cool(er). Besides, when using the factory programming, the TC will unlock at 14-16 MPH and then the enabling conditions have to be met again to lock it up.....when pulling horses, it's not too nice to jab the throttle in second gear.

 

Great minds think alike I guess...

 

OK I am not sure on something here. Cody, you said you lock the TC in first gear under 15MPH? I thought I read on here somewhere not to lock the TC at anything under 35MPH for pressure perposes. Is it ok to lock it at 15MPH in first gear and go there the gears like a manual while still keeping it locked? I would like to know so I don't kill my tranny.

 

Cody:
Can you similarly describe the box code for my 02? I have never seen the TC lock up in 2nd at any speed. Thats why I added the lockup switch.
Warren

 

I can't say about your transmission pressures, but I started doing my own tuning and raise the pressure a little in my low-HP towing tunes just so I can do this safely.

The thing about the lockup at low speeds is that you are sending a LOT of heavy firing pulses through the transmission with the torque converter locked up. If you've lugged a lot of manual transmissions, you know what the truck is going through. I kind of mis-worded the original post....I don't like to lock at less than 15 MPH, but on the other hand, it's a lot easier on the truck to let off the throttle, flip the switch, and then ease back into it versus getting into it heavily to force a lockup....not a real smooth transition, especially with the overly "loose" converters these things come with.

As for the shifts with the torque convertor locked:
The shifts will not be transparent, that's for sure. Usually on a stock truck with a stock convertor, you will get a drop in RPM during unlocked shifts, but not really feel the shift. With the torque convertor locked, you WILL feel the shift. Is it bad for the tranny? Depends on what kind of accelerator pedal position (APP) and what you're pulling. You will get firmer shifts, but at the expense of being at the mercy of how quickly the shifts occur.

As for describing the 02 box code:
I do not yet have too much experience with these ones. I have one truck to work with and the owner is trying some stuff out for me.....I'm learning about it. So far, I don't like the way Ford "hard-wired" the PCM to make transmission tuning for them difficult. In difficult, I mean, no matter what is done with standard tuning software, TC lockup at full APP isn't possible, the TC will always unlock with a delayed re-lock on a 4-3 shift, and since the introduction of CAN (controller area network), the standard tunes for 99-01 won't work right. Jody (DP-Tuner), as I understand it (heard in different forums) has worked around these issues (don't quote me though) for the 02-03 trucks. He's a frickin' wizard on these things and is an amazing tuner.

I have much to learn and a lot of time to spend .

 

Don't lock the torque converter below 1300 RPM. If the engine is below 1300 RPM the pump won't be making enough pressure to make sure the converter stays locked and doesn't slip.

 

I lock mine all the time below 1000 rpm's, but its stock, and I am very gentle on the throttle till it gets around 1400-1500 rpm's.

 

Yes, the Tru-Cool is in series w/ the stock cooler.

Speeds were anywhere from 10-40mph....lots of switchbacks at 10-15mph.

Going in I pulled it in 2nd and temp hit ~250 before I could find a place to pull over...you could really smell it. Coming out I left it in "D" or 3rd and the highest temp was ~230. Both for short periods before getting stopped. Going in is the toughest/longest up hill pull.

I don't know where the sensor is located.

I also have a BD exhaust brake and TC controller which I think keeps the TC locked when it is engaged. One problem I saw was that the brake drops off ~28-30 mph and much of the downhill is tight switchbacks requiring 10-20 mph.

As I said, truck ran and shifted great with no temps over ~180 and most of the time ran ~165 out on the open interstate running 65mph.

Thanks for the replys so far.

 

I would definatly change the fluid with it getting that hot then. Might want to make sure you change all of the fluid out, since it got so hot. Also if and when you pull that hill again you may want to shift the transfer case to low range. I do it with mine sometimes and then it seems like I have both more control over speeds and alot of torque to climb the grades with, especially them switchbacks. Just remeber your max speed then would be around 30 to 35 mph.

 

Mark, that is a good point you make, that no one brought up, we do have a simple electronic solution for this called a Pressure Loc


wildbyon, Did you know the T/C release speed was adjustable on the BD lock up controller you have? I can likely lower it to about 18MPH for you very easily if that helps. Contact me and I will walk you through it, I will near the rear end ratio.

Also if you are looking for transmission coolers we have a great set up, click here to check em out, available with temperature activattion at ~180 or with toggle switch. Other options we offer for cooling is obviously our BD Aluminum Pans and our Cooler Bypass tube kit. You will not find these bypass tubes on our web site but they are about 25 bucks and ship with every BD exchange transmission that leaves here! Removes the cooler bypass and the restriction it causes.

Hope this helps...