I have an 09 Fx4 with 12K miles on it and flat towed my 74 Bronco (approx 4400 lbs) up to Big Bear Mnts in So Cal from San Diego for the first time last weekend. There are a few steep hills leaving San Diego and the truck did fine, cruising up to 70 without any stress and low rpms. Hit the bigger grades of the mountain roads and still did fine altough I was confused on where to put the trans (tow haul or not and manual shift or let it do its own deal) shifter settings. It seems like it did not want to down shift unless I really stepped on it or manually down shifted to 2. I will say that it was dark and foggy so I was more focused on the road than experimenting/remembering where I had the trans set but it did seem to be in between gears or not want to downshift.

Also, ended up having a hell of time with the wheels on the bronco not wanting to turn in corners. I have been flat towing this bronco for almost 20 yrs without an issue. Not sure what has changed on the bronco - new truck though. Motorhome and old 1970 F250 didnt do this. Any ideas? For gauging if the steering wheel was moving I zip tied a white rag on the steering wheel on the way home and when the tires were bounding up on the bronc the steering wheel was not following the curve of the road. Kinda thinking the bronc is due for an alignment.

All in all, the truck met my expectations towing wise and felt great breaking, turning, climbing all while towing. Pretty decent mpg too. Just need to work out the alignment/tires binding on the bronc and trans gearing selection.

 

You should have the T/H mode anytime you are towing or hauling anything over 1000 lbs.

Put the truck in "D" and let the tranny do what it's designed to do. 3, 2, or 1 limits you to the selected gear.

 

Did you remove the driveshaft from the Bronco while towing it? I am assuming you mean you are towing with a tow dolly or tow bar? If the rear tires are turning while you are pulling it, you need to remove the DS or your t-case will be destroyed....Could have something to do with the binding too...

 

I live in Running Springs and use the tow haul mode to come down the hill even with out my trailer. Going up it doesn't want to shift as it holds the gears longer to protect the tranny.

 

My grandparents own a cabin in Running Springs, though I haven't been down there in probably 13 years.

 

While I would agree in this instance you should have the T/H mode on for hauling the load that the OP was hauling, where he was hauling it. I would not agree with the anything over 1000 lbs statement. 2000-2500 maybe for the 150, but not 1000.

 

Does your Bronco have a locking front Diff? If so, is it an electric lock, or spin lock. If that were locked, that would certainly make it not turn.

The other thing is, does it have a locking ignition key, that locks the steering wheel when off. I know you have pulled this thing for many years, but could you have forgotten something that you used to do.

Also, you should be able to put your transfer case in neutral and pull with the drive shaft in it. That should not hurt anything.
Could you have had the trans in neutral and the transfer case in 4X4? That would certainly make it not steer correclty. Just a thought.

 

With the old 4 speed, okay. With the new 6-speed and tall 5/6th gears, I think you're doing your tranny a favor by using T/H.

However, with no number in the manual, my opinion is just as invalid as anyone elses!

 

This is completely wrong advise! IGNORE! Do not tow a 4x4 with the rear tires on the ground spinning unless the driveshaft is removed! The driveshaft will turn the transfer case and the oil pump in the T-case will not be circulating lubricant! This equals a destroyed T-case!

 

Doesn't this depend on the tcase?

 

yup my 79 ford has no pump in the t-case. the case is half full of gear oil. that lubricates all the bearings and the gears. pretty sure he should have the same case as me. as for the front tires. not sure.

http://www.offroaders.com/tech/Diagrams/np205.htm

 

This is an interesting statement. So coming up the hill (used to live in Crestline so I know the lingo) with the tow haul on could make it stay in a gear longer potentially loosing rpms? I agree the tow haul on is nice when going down hill.

 

Good point, it has a detroit locker in the front and for some reason the hubs might be locked or front portion of transcase engaged. Tcase is a 3 speed with 3 shifters and I may have not gotten all into neutral.

 

I agree but typically do not unhook driveshaft for short trips - 100 or so miles. This has worked for years. I even towed my bronco to the high sierras (400 or so miles each way) before I knew any better. I have heard of people tcase burning up bearing though.

 

It's dependent on speed, torque, and throttle position.

I find the T/H downshifts slightly quicker when I'm towing uphill and it takes less throttle to get it to downshift.