Hi forum members, I hope I can get some ideas about an issue with my truck. First the specs: '99 F350 DRW 4x4 7.3L auto 5/99 build date 150,000 miles and total stock no mods. Over the 4th of July weekend I was towing my bumper pull toyhauler (about 8000lbs) and it seemed like the trans was shifting too early and not upshifting when it should. This was on level to slight upgrade rolling desert road (US 395 to those that might know) I have a '99 with the ZF tranny also and on the same road with the same trailer I am accelerating in OD, this truck seems like it does not have the power to pull. I also noticed that with the A/C on my legs were getting very hot. I pulled to the side of the road and found the firewall was too hot to touch, the brake pushrod from the pedal to the master cylinder was untouchable as it was so hot and the parking brake and computer housing were also extremely hot. I popped the hood and found the fenders on both sides and all the engine componants were extremely hot. However with all this the enging temp gauge stayed in the lower half of its range. It seems to me that it was a lack of heat dissipation vs an engine overheat. Could this have been from the engine rpms being between 2500-3200 trying to maintain 65 mph? Could I have a transmission problem or would a worn turbo lead to this as my "wicked wheel" has a couple of bent vanes and chipped edges. Driving the rest of the way home keeping it under 2500 rpm the heat issue went away. Any imput would be helpful as I need to know where to start looking for a fix

 

I would start by inspecting your up pipes at the rear of the engine. If you find soot, there's a leak. Sounds like this could explain all the excess heat you described on the firewall.

Your "power" issue is probable a combination of other problems. If your truck is completely stock, you have a 9 plate tranny cooler that is WAY under sized for you transmission. This causes the tranny to heat up a lot, and some symptoms are slippage and strange shift strategies. Sometimes it'll puke fluid out the front of the tranny due to the seal getting to hot, and becoming compromised.

If I were you, I'd seriously consider upgrading the tranny cooler to the 6.0l OEM cooler. It has substantially greater cooling capacity.

 

It does sound to me like your transmission was slipping. Obviously I can't say for sure, but if you were having to hold 2500-3200rpm to maintain 65, the power isn't getting to the wheels. A trans temp gauge probably would've given you some useful information.

 

I will look at the up pipes for soot. How do I go about installing a tranny temp gauge?
Thanks for both of the replies!

 

If you have the stock trans your doing good. Trans guage is easy. Theres a port on the side of the trans for the sending uint. Talk to Clay at riffraff diesel, he has all you need. I wouldn't tow with that set up without a trans gauge even stock. And I'll bet your uppipes are leaking its normal with that kind of mileage. I have the same truck and am going to do mine. Its not that hard but does take time. Check your trans fuild and see if it is burnt or low. Theres a good chance it could be if it got hot. Chet