I've towed my 4,500# trailer about 4 times (about 1500 miles) since I got my new Super Crew ('03 Fx4, 3.73 gears, 5.4 Auto, about 6,000 miles on it now). I tow locked out of overdrive all the time while towing. It tows great and shifts fine except under one condition. When going up steeper hills, it will down shft to second and rev up to about 4K RPM (at about 60 MPH). The problem is it won't up s h i f t at the top of the hill. I have to let off the gas and slow down to about 55 MPH before it will up s h i f t to 3rd again. I just hangs there stuck in 2nd no matter what I do. I don't like it revving that high for too long, but it won't up s h i f t. Any ideas?

Thanks

 

Sounds like what my truck does, and my freinds. And probably all of them do it.

I think I read a similar post a while back that the computer will lock you into second until you let off the gas. Something about it sensing that you are under a higher load than normal. I guess you could call it a self preservation feature

Rob

 

Yep, it's a smart PCM. If you were making more power, it would likelyt shift sooner as the engine could pull that grade better. The thing will hang there for a short while until it "detects" that you're not under a load anymore.

I have a few mods and "ALWAYS" tow with OD on. It's smart, it knows when to shift where. My load is over 7000#.

Every now and then when towing in the extreme heat, AC on, on a grad or entering a freeway mine will stick around in 3rd for a while. I'll sometimes just let off a little and it'l shift bacu into OD. From there, I don't use cruise and work the up and down grades. Works well and I'll get 11-12 MPG doing that!! I'm really surprised how low the RPM's will get (1200 or so at a low) and still pull a hill holding a decent speed. On the hwy I'll hold 55-60 on a hill at 1600-1800 RPM or so. Tell me where the Ford makes grunt

 

Yeah I think they all do it. I noticed once, when I was towing a camper in a gusting headwind, that mine would shift down when the wind picked up and was blowing onto the trailer thus simulating a larger load and then shift back up when the wind stopped. Makes sense to me. I don't think my tranny will become "self aware" tomorrow or anything but it does seem pretty smart.

 

Mine does the same thing. I momentarily turn the overdrive on and it shifts back into third, then I turn the overdrive back off. Hope this works for you.

 

Thanks,

At least it sounds like its "normal". I'll try the overdrive trick next time.