Jmac

Can someone briefly explain to me how/when/which of these features to use when towing? I've tried the search function and have had little success.
thanks in advance,
Jamie

ptgarcia

Don't know if it's right, but this is what I do and it works great for me:

- Whenever towing (my trailer and golf cart combo weigh in at about 10,000 lb total load) I engage Tow/Haul mode.

- If the tranny starts hunting, shifting in and out of overdrive trying to find the right gear, I lock-out overdrive. Once on flatter terrain I put her back in Tow/Haul mode.

That's all there is to it.

hubmonkey

I can't speak to the over drive off since my 05 does not have that feature but I will explain as I know it.

Overdrive on and tow/haul off... Everyday driving without hauling any thing.
Overdrive on and Tow/Haul on... Dreiving while pulliing a trailer or heavy load.
Over drive off... When towing or hauling a load and the trans is hunting for a gear... example: pulling a grade and it goes into overdrive at 48mph, you apply the pedal and it drops down to third. You can lockout the overdrive and stay in third.

What I do when towing my RV is tow/haul is on because the way I understand it is the Trans changes the shift points and increases the line pressure to give you more positive shifts.

Hope this helps and is correct.

Hub

bigdav160

The tow/haul feature increases the fluid pressure for more holding power. It also slightly modifies shift timing for better performance. The most important feature of tow/haul is it brings on the bands normally used in the manual transmission ranges to provide engine braking on decelleration. Some claim it keeps the torque converter locked up on decell but I haven't seen that in any documentation and my truck doesn't have tow/haul to verify.

OD off allow for manual shifting to third. Important is the load is so heavy that fourth gear with TCC lock up cannot be maintained. Also provides engine braking in third and early third TCC lock up.

dale29

I would add to this, that you use tow/haul whenever towing period, whatever the weight, and that you can use the OD off setting to maintain control on downhill grades (when towing or not).

Foxborough

I'll add my 0.02, in also. Tow haul also down shifts under breaking. Works great with my #6000 boat use it every time I haul. I have used the O/D lockout a few times.
In stop and go traffic at speeds under 50 mph O/D lockout really works great, lots of power (only three gears). The transmission runs cooler also when stop & go, used it towing thru Chicago. Used the O/D in the Ozarks, Osage Beach Missouri, stop & go and really hilly lots of traffic. Transmission gauge went up to 190* pretty fast. Switched to O/D and temperature dropped fast.

v8440

Tow/haul does indeed downshift during deceleration. Another thing that has not been mentioned is that it locks the torque converter earlier. In tow/haul, the converter will lock if you manually select second gear (something it won't do in normal mode), and if left in drive it will lock at 30 mph in 3rd. The truck will also upshift to 4th a little EARLIER in tow/haul at light throttle. It's about 2-3 mph earlier. In normal mode, it won't lock the converter until it's in overdrive at 49 or 50 mph at light throttle. I believe tow/haul will give slightly better unloaded mileage around town due to the earlier converter locking.

jrussell

Sorry to bring up and old thread, but I didn't want to start a new one for this question.

Why on earth can't you use Tow/Haul and lockout the O/D at the same time? What if you're towing in hills and still want to lockout the O/D? If you choose to lockout O/D then you lose Tow/Haul and all the benefits it provides (ie. added engine braking). Having both these features on the same switch and not being able to use them simultaneously seems like a really, really bad idea.

Foxborough

I believe you would do that if you had it tow/haul mode & shifted from D to 2. You would have all you wanted unless I missed something. I'm not familiar with the lanscape in your area. I am a flatlander only see hills in Missouri & Kentucky.

jrussell

Yeah, I see what you're saying. It just seems odd because there are situations where O/D is too high and 2nd is too low. Let's say you're towing in hills with some flats mixed in and don't get over 40mph. It would be nice to have O/D locked-out and still be in Tow/Haul mode in 3rd gear. If 2nd - 3rd gear needs to be used you can't have it in Tow/Haul mode while the O/D is locked-out?

Does anyone else have this same issue?