Questions on towing

[orygunf150]

Had my first experience towing with the f150 w/ gryphon. We bought a toyhauler, well to haul our toys of course. It's only 20' total in length and only weighs 4500 lbs. We towed it home about 180 miles in 100 degree down
I5 in tow mode (level 2) encountering a few 6 % grades. This is an 05 f150
4x4 with the 5.4, 3.73 gears and 235/75/17 tires. Being a little concerned about the temp I monitered engine coolant temp as wall as tranny temp. On flat roads coolant temp ran about 190, tranny about 175. At the top of the hills I was about 202 and 195. I think those temps are not bad towing in 100 degree weather, opinions? At what point would you become concerned with tranny temps? On to the real issue, driving on the flat areas at about 65 mph in overdrive the torque converter seemed to hunt between lock and unlock (I was also monitoring comm gear) so I locked out the overdrive towing locked up in 3rd. FWIW the tranny temps didnt seem to be affected by the hunting or the gear change. I was a little surprised that it wouldnt hold 4th gear locked up since this isnt a lot of weight and the fact that I have 3.73s and smaller tires. I recorded the following at 65mph:
4th gear locked up: 1900 rpms
4th gear unlocked: 2500 rpms
3rd gear locked up: 2700 rpms
This brings up the age old question, should I tow in overdrive or not? Also, should I customize my tow mode, or have a custom program made?
Opine at will............Mark

[04FX4]

Never tow in OD. Check your manual. As far as your temps go I see no problems. My truck seems to tun around 200 with out the trailer and with I have seen temps of 212 going up some real steep hills and tranny temps of 225. I think I may invest in a tranny cooler and may replace my t-stat. My truck seems to be running to hot at least I think so. The temp here today was over 100, and driving a short distance down the highway it ranges from 198-202, empty.

[Jackpine]

I moved this to the Towing forum, since that's the subject of the thread.

I want to disagree just a bit with the advice about overdrive. My owners manual does not say to turn O/D off when towing. On page 185 of my owners manual, it says, "Turn off the speed control." (This seems to be due to the fact that the speed control will easily disengage when climbing hills while towing. I correct for that by manually feeding gas on hills to prevent slowdown)

On the same page, it says: "To eliminate excessive shifting, use a lower gear. This will also assist in transmission cooling." If I find that the transmission is starting to shift between 4th and 3rd, I lock out the O/D. If I find the transmission starting to shift between 2nd and 3rd, I move the shift lever into 2nd.

On page 202, the manual discusses driving with the O/D off. It says:

1. "Provides engine braking." I use this on long downhill stretches to control speed. I don't like to use the brakes. If I'm still using the brakes in 3rd gear, I drop it into 2nd.

2. "Use when driving conditions cause excessive shifting from O/D to other gears. Examples: city traffic, hilly terrain, heavy loads, trailer towing and when engine braking is required." Notice it is not talking about the Torque Converter (TC) here.

However, I really agree with you, 04FX4, in your philosophy. If I find the TC starting to frequently unlock and lock back up, I turn the O/D off. In any kind of driving, towing or not, I try to minimize gear shift and TC activity.

The temperatures you see, orygunf150, are perfectly normal. I have bigger tires, and I regularly see TFT in the 214-216 range during a long hill climb. The useful life of the transmission fluid is shortened. (Probably cut in half).

Engine temps in the 200-210 degree range are exactly what you want for efficient engine operation. This is where the engine is designed to operate. Don't try to get it to run colder. It can actually be harmful to the engine and will hurt your fuel economy and power.

One more thing, orygunf150. A toy hauler has a pretty high profile (big wind resistance). If you can stand to do so, drive slower when pulling it. In any case, don't go faster than 65mph, unless you have special high speed trailer tires.

- Jack

[Jackpine]

Mark, I see I did not answer your last question.

I think Bill could optimize your tow tune over the canned one given that you are running on smaller tires and are pulling 4500#. I'm pretty sure the canned tune is set up for somewhat higher weight and perhaps a different effective gear ratio. Even if it's not, Bill will improve on the performance of ANY canned tune if he customizes it for you.

- Jack

[04FX4]

I have read many post about this and most say DO NOT TOW WITH OD ON. I do not tow with OD on, I have also seen people post about tranny troubles when towing with OD on.

[Jackpine]

Originally Posted by 04FX4

I have read many post about this and most say DO NOT TOW WITH OD ON. I do not tow with OD on, I have also seen people post about tranny troubles when towing with OD on.

Peace, my friend! I'm not disagreeing with the substance of what you said. I just pointed out that MY owners manual, at least, did not say to turn the O/D off when towing. And, it doesn't talk about TC unlocking and locking. I simply don't think there are "cut and dried" rules here.

I've not experienced any transmission troubles by letting my transmission tell me what to do. I tried, for a while, towing with the O/D off. It seemed like the engine was revving much too high all the time. I decided to put it back on and things got a lot quieter and the truck seemed to be pulling without effort. Please notice I DO turn it off when hill climbing or hill descending. And, I shift down to 2nd on really steep hills (both ways).

I don't think we're saying much that's different here, and I've really appreciated the input you've given us on this subject.

- Jack

[JWBFX4]

Originally Posted by 04FX4

I have read many post about this and most say DO NOT TOW WITH OD ON. I do not tow with OD on, I have also seen people post about tranny troubles when towing with OD on.

Well I am sure I might be repeating something already said, because I didnt read everything but.

As pointed out earlier...let your tranny tell you whether you need to OD on or off. This is especially easy when you are monitoring comm gear. If you see the TQ locking and unlocking a lot or shifting in and out a lot, you just need to lock it in 3rd OD off.

I don't regularly pull heavy loads, but when I do I keep OD off untill I hit and maintain highway speeds then turn it on. After that I turn it off at all hills and also lock it in 2nd when need be. But its to each his own on the situation.