NC F150

My 2007 f150 has the 3 speed auto with overdrive. When pulling our 4300lb TT should I leave it in drive as usual or are there times when I should select the gear and shift manually? Turn off overdrive? Etc. no transmission temperature gauge to monitor? It came with the factory external transmission cooler. 3.73 rear end.

Does overheating usually occur when driving at interstate speeds or just mountain driving? Is it better to drive in a lower gear with higher engine revs or higher gear?

I know. Lots of questions. I'm just very new at the heavy trailer towing. Figured I'd rather equip my self with knowledge than a tow truck and a even thinner wallet. The travel trailer has already taken care of the wallet. 😄

smokeywren

That sounds like the 4R70 tranny, which s very similar to the 4R100.


On my F250 with the 4R100 tranny, one of the engineers that developed the tranny said to put it in drive and let the computer select the gear based on conditions. The exception is if you see a steep grade ahead that you know is going to cause a downshift, then get off the go pedal, manually downshift (or kill O/D) and then get back on the gas. Allowing the computer to downshift will usually cause a much more abrupt shift than doing it manually.


Also, when coming down the mountain, manually downshift to 3rd or maybe even 2nd to getsgine braking to prevent too-high a speed without having to ride the brakes.


Quote:
no transmission temperature gauge to monitor?

If you don't have a tranny temp gauge that gives you tranny sump temp, then you're gambling with your expensive tranny and torque converter. I would install a good tranny temp gauge before doing any more towing. Here's one:
http://www.egauges.com/ProductDetail...uctCode=R13599




Quote:
It came with the factory external transmission cooler.

That may or may not be adequate. If you ever see over 220° tranny sump temp, then it's not adequate - you need a bigger tranny cooler.


Normal tranny temp is anything up to around 210°. 210° to 225° is the pay attention! zone. You're hot, but not too hot. 225° is the red line. Over 225°is too hot.

Quote:
Does overheating usually occur when driving at interstate speeds or just mountain driving?

Rarely at interstate speeds, even when climbing interstate mountain passes as long as you maintain highway speeds over 45 MPH. Overheating is caused by high-torque (engine working hard) and low speed so the torque converter unlocks. An unlocked torque converter with the engine producing lots of power and torque throws a volcano worth of heat at the tranny cooling system, overcoming the tranny coolers.


For example, dragging a trailer up a steep, crooked mountain trail where you cannot maintain at least 45 MPH is a sure way to cook your tranny.



Quote:
Is it better to drive in a lower gear with higher engine revs or higher gear?

Your tranny temp gauge will tell you which is best. With a powerful engine, you probably want to slow down a bit and maybe downshift to keep the revs up near the HP peak when climbing an interstate mountain pass.

TLB4

4300 pounds isn't too bad of a load. Just leave in the overdrive on the flats, and use you best judgement for hills. Your tranny cooler and tranny temps will be fine for that load. Don't worry about it. Especially with 3.73 gears. Hook up and go.

NC F150

Thanks again.

Appreciate it.