well here is the latest, today I hooked up to my car trailer, about 2200 pounds, and loaded a 3000 pound car on it. I drove about 3.5 miles to the freeway, it went from cold to 220* in that time frame, roughly 8 to 10 min. I got on the freeway and drove about 14 miles and it was at 160* with in a few miles of the on ramp. I got off the freeway and went about 3.5 miles in roughly 5 min and by the time I parked the truck it was at 250*. I unloaded the car and sat and talked for about 35 min. Got back in the truck and the gauge was below 100* again. Fired up the truck and went down the road about 1/4 mile or so and it was climbing past 180* and almost to 220* by the time I was back to the freeway. 160* all the way home till I got off the freeway, and at 210* by the time I got home. I let the truck sit for 30 min or so while we loaded a second car, and when i fired up the truck, again, below 100*, but back to 170* before I could get to the end of the block. I drove about 3 miles to deliver the second car, and again 220*, let it sit for about 35 to 40 min, and got back in and it was at 110* and back up to 190* with in a 1/4 mile or so. At this point since this gauge is electrical, I am wondering if the probe or booster box is going bad. It seems very odd to me that the temps would climb so fast and in such a short amount of time. Oh, and just for those that will ask, it was cloudy and over cast most of the day and high 70's. i am going to go remove the bully dog to see if it has any thing to do with it, but i am doubting that it will. I will type more later.

 

tranny fluid is a different animal- it dissipates heat quicker than any other fluid. after you shut the truck down and wait a few minutes-the gauge will read low or on the cool side-but as soon as you start driving again after a relavative short shut down period (after driving for awhile) the temp will go up to basically the operating temp because all the internals,etc in the tranny along with the fluid are still warm to hot-the fluid is starting to cool when you shut her off after a drive-but at the same time the tranny fluid is not yet totally cooled-so as soon as you drive her again, before the fluid has totally cooled it will be build up heat quicker-yence your quick operating temp readings.

 

Trans fluid is different....not that much, though.

IIRC, You have the trans temp sender in the 'hot' line from the trans to the coolers, right? If so, what you are seeing, after sitting for 10-30 minutes with the truck off is a VERY small sample of fuid in the cooler line cooling off. Upon restart, hot fluid starts flowing again, heating the cooler line until the cooler line is up to temp.

FYI...On most (maybe all) DC vehicles manufactured since dirt, do NOT flow trans fluid in park...Only when in gear or neutral.

On the 04.5, do you have Tow/Haul mode? If you do, try it the next time you tow & check trans fluids. T/H on the '06 models lock up the TC pretty early as early as 30mph.

You could have a TC going out...It sounds like your TC is slipping. For the distances you are driving, the trans should not get THAT hot.

HTH

Tony

 

Just hauled my 5ver from Mass to Myrtle beach S.C., 2,200 miles round trip, trans temp driving at night- 145-150, loaded. During the day ambient temps at 75-80 deg the trans would run 160-170 deg. all at highway speed with the tc locked and trans in tow haul. Once off the interstate I would see the trans temps climb as high as 190, but in tow haul the trans locks in 3rd so the temp would come down to 160 again rapidly. All this is with the probe in the hot line and a Mag-Hytec dd pan from Diesel Manor. I also run Lubrication Engineers Trans all 1150 EHP trans fluid. The hottest my trans got was on the way home last night, while sitting on a 4% grade in traffic moving at a crawl for 2 miles waiting to cross the GW bridge in NY, the trans temp was at 250*, I was constantly on the throttle just enough to keep a snails pace with traffic, my skin was crawling looking at the gauge rise, ( O also noticed a tc shutter ) once I cleared the toll booth traffic avg 30 mph and my temp gauge fell back to 160 within 10 minutes.

 

I suggest you put it in neutral whenever possible in that situation. The owners manual even state to do so.

Netral will unload the TC (stop generating heat) while still pumping fluid.

HTH

Tony

 

Thanx Tony, I usually do put it in nuetral, even at traffic lights, the only problem is traffic was constantly moving at a snails pace so in this particular situation I was caught between a rock and hard place. This truck has had the shutter since new also, the dealer stated it was normal for a long wheel base to do it. It is almost unnoticeable empty, but hauling my 5ver it gets very noticable from a start then disappears at appx 1700 rpm, only does it in 1st gear.

Thank you for the heads up. Tim

 

You're welcome!

How heavy is your 5er? I've had up to ~7k on my flatbed and have not noticed the shudder. And, yes, I do have a log wheel base, too!

Tony

 

My 5ver and truck are 21,700 gcwr. I go light on the throttle on take off when loaded and it seems to minimize the amount of shudder I get, the harder the accleration the more pronounced it is. I took my truck into my shop at my part time job and messed around with the carrier bearing spacing, it did not make any difference at all, plus with my 5ver sittin on the truck the drive shaft alignment looks pretty good. Besides the reflash I just had done, it is the only problem I have had with this truck, the trans shifts and performs very well.


Tim

 

UPDATE:
I drained the tranny out and unhooked the hot line at the body and pushed air into it and flushed the cooler. Changed the filter, installed the PML pan and added back 11 qt's of Valvoline ATF +4 Synthetic and the tranny shifts great, the shutter that was there in first gear is gone, but the temps are still high. 190 in about a 6 minute ride, and for those that will ask, yes it was a quart low when I went for the drive, but that shouldn't have made that much of a difference. So at this point, I am still stumped.

 

Rob, good move on the new tranny pan. I would not have put compressed air to the cooler line simply because it takes fluid to flush any thing out, air will not hold anything in suspension to carry it out, air will usually dislodge debris then push and pack it in places you don't want it. If you want, you can take the rear trans line off the transmission put a 2 or 3 foot hose on it and drop it in a bucket, then put a funnel in the dip stick tube and with the truck running in nuetral add 5 or 6 qts of fluid, that should be enough to flush the lines and cooler out. Its actually pretty easy to do, also if you have help to add the fluid to the trans, you can watch the fluid pump into the bucket, you should have a solid stream of fluid returning to the bucket.

Let us know what you decide. Tim

 

Tim,
I already did that before I posted. Once i unhooked the line, it started draining out of the port on the body. Once that stopped, I put the old pan back on with couple of bolts and I pushed the air in to the line. My concern was the amount of pressure, not knowing what kind of line pressure the pumps make, I was worried about pushing to much through it. In the end I had to use full pressure (125 psi) to push all the fluid out and got about another quart of fluid out. I used the hot line to push the air into, so the return line could dump any garbage into the pan, but when I looked at it, the only thing I saw was a definite hint of clutch dust. The truck has 146,000 miles on it and I am starting to think that it wasn't maintained properly. To many little things that should have been done, haven't.

 

I hear you on that, unfortunately, unless you know the buyer or they hand you a stack of reciepts and records, you just never know for sure. Best of luck on resolving the issues.

Tim.

 

RobC, I just went to tucson and back unloaded doing 79mph the whole way. My temps on the highway were about 150-160 as soon as I pulled off on to surface streets it jumped up to 180-190 but never higher than 190*. So far I haven't seen anything near 250* like you have. But so far all my results have been unloaded.

 

If mine hit 250 I would change the fluid as soon as possible. I understand that it begins to break down at about 215. I've only seen mine go above 215 one time, and I was pulling a 5er in the NC mountains, running slow in 2nd gear. I pulled over and let it cool. Hope you don't have a major problem.

 

At this point I don't know what to think. I went for a drive tonight and I went about 8 miles up the road, shut the truck off for about 10 minutes, and then drove home and it was just over 190 when I took off for home. At one point, I managed to get about a 4 mile run where I got all green lights and it dropped to 175. But it was back to 190 by the time I was back up to speed after a red light and while I didn't look, the outside temp was probably in the mid 70's. The tranny shifts great now that I have changed the filter and oil so that has helped. The pan hasn't done a thing to help, so that was a waste of $200 bucks. Is it possible for the tranny cooler to get plugged up or blocked off on the outside?