Towing and transmission issue

RGSMDNR · #1 Tue, September 15th, 2009, 09:07 AM

I have an 07 f150, 5.4 supercrew...

I tow a 25' travel trailer that weighs about 5000lbs. My issue im having is maintaining highway speeds when the tranny heats up. Its fine around 150 or so... but anything above that the truck seems to run like a dog. It doesnt matter if im using the towing tune or running stock. To be honest i dont run the towing anymore because it doesnt have any top end. It seems to run better stock. Any thoughts on why the truck doesnt make any power when the tranny heats up?

thx

***88Racing*** · #2 Tue, September 15th, 2009, 09:15 AM

How many miles on the truck and last time tranny fluid changed?
Also what's the highest temp the fluid has gotten to?

Lars

RGSMDNR · #3 Tue, September 15th, 2009, 09:18 AM

There are about 34000 kilometers on the truck. Ive never had a tranny service done. I think the highest temp Ive seen is about 200.

***88Racing*** · #4 Tue, September 15th, 2009, 09:27 AM

If you have done a lot of pulling with the fluid from the factory I would suggest getting it changed.
Probably a synthetic like royal purple might do a better job than motorcraft if you pull a lot.
But just in case I wll post a note on the mod board.
200 is getting close to break down temp. Let me find that number and get back to you.

Lars

RGSMDNR · #5 Tue, September 15th, 2009, 09:30 AM

I guess im just disappointed in the lack of power this truck has while towing. I wasnt sure if it had anything to do with the tranny temps or not. I dont pull all that often, but when i do its just frustrating trying to maintain highway speeds without having to step on it every so often to get it back up to speed. Would the hotter tranny temp be robbing that much power??

***88Racing*** · #6 Tue, September 15th, 2009, 09:40 AM

I am going to have to try and draw Bill's attention to this issue.

Lars