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Super D
04-11-2003, 10:10 PM
Ok, I'm not a rookie to towing, but I'll make you wonder anyway:
Question: When towing, do you lock out overdrive 1) Always 2)only going up or down hills (engine brake), or 3) never.
"Tow/Haul" mode goes into OD, but does GM really know what's best?

JustMVG
04-11-2003, 11:00 PM
It depends on the drive if i am going up the Grapevine i'll turn the O D off to keep it from going back and forth , but for the most part i leave it on. My .02 for what it might be worth. Mike VG

Havasu Hangin'
04-12-2003, 08:31 AM
I think GM had trouble with thier earlier trans when towing in OD...with my 98 Hoe, I never towed in OD, s I was told it would kill the trans (going "in and out" like MandMVG pointed out). Until I sold it, 77K miles without a hiccup.
On my new Burb, it would appear that GM has addressed the problem, with the "tow mode". I haven't got enough seat time to tell when it kicks in (or doesn't)...

mtndewdrops
04-12-2003, 08:09 PM
I towed a 3200 lb boat with a Chevy Astro Van for 4 years and towed using overdrive without a problem. I have heard of people that didn't tow in overdrive and had transmission problems. :confused:
I do know that in a lower gear the transmission lube pump is turning faster and therefore cools the tranny more effectively. :) When traversing steep grades it is a good idea to take it out of OD unless you have a healthy transmission cooler.
I currently own a '01 Yukon XL 4X4 :cool: and am still undecided that the tow/haul mode is better. I go back and forth. wink
Dennis

lovemyultra
04-12-2003, 08:19 PM
I keep mine in OD most of the time but Im only towing a 21 with an F250 and a 460

Trash
04-12-2003, 09:13 PM
Check the owners manual. For my Bronco it says its okay to leave it in OD unless it begins to hunt between gears.

rivercrazy
04-12-2003, 10:47 PM
The right way of doing this is: What ever gear uses the least amount of throttle is the right gear on flat land towing. Always pull it out of OD on hills.

Party Cat
04-13-2003, 02:58 AM
Havasu Hangin':
I think GM had trouble with thier earlier trans when towing in OD...with my 98 Hoe, I never towed in OD, s I was told it would kill the trans (going "in and out" like MandMVG pointed out). Until I sold it, 77K miles without a hiccup.
On my new Burb, it would appear that GM has addressed the problem, with the "tow mode". I haven't got enough seat time to tell when it kicks in (or doesn't)... With the 460LE tranny, the problem with towing in OD arises when the converter unlocks. When this happens, the volume of tranny fluid that goes to the cooler is drasticaly reduced and ya wind up overheating the tranny and converter. Ya can solve this problem by droping the shifter to '3' like MandMVG pointed out. A bigger tranny cooler also helps....
PC

Powerquestboy
04-14-2003, 02:03 PM
I just got rid of my 99 Yukon, I always took it out of overdrive when I towed, It would downshift every time I hit the gas if I left it in OD. A few times I was on flat enough ground for a long enough time that I put it in OD. I have a new Yukon XL now and have only towed with it once so I’m undecided on how well the Tow/Haul button works for my boat.

77charger
04-14-2003, 06:19 PM
I have no choice but 1,2,D.
But its a turbo 400 :) :)
Anyhow i have heard to leave the o/d models in drive if it's a 700r4 or a 4l60.My worktruck is a 97 chev 3500 with the 4l80 trans and i tow in o/d with that.

Mohavekid
04-15-2003, 10:18 AM
It depends on the weight and the terrain.
My boat is relatively light, and most of the time on relatively flat ground I leave my 99 Surburban with a 7.4l in OD. On grades I down shift to 3rd.
My old Challenger jet was very light and I almost never shifted it out of OD.
A real tranny cooler helps a lot too.

SCUBA STEVE
04-15-2003, 02:24 PM
on the big 99 dodge ram, the manual says to tow out of o/d. I tried both, it seems out of o/d works best for me.

MOPAR2YA
04-15-2003, 06:44 PM
Lot's of good info all around. The #1 reason for trans failure is overheating. If you control the temperature (tow package), usually won't have any problems. I agree with you guys that most late model overdrives trans are alot better than older styles.

Chase
05-02-2003, 02:21 PM
I am pullig a 3500 18.5 foot boat with a 98 GMC 1/2 ton and most of the time I leave it in OD while pulling. I do however keep track of whether the torque converter is locked or unlocked. I also have a tranny temp guage to monitor how things are doing as well. As mentioned above as soon as the TC unlocks the temp climbs very fast, so if the TC is unlocking frequently I will bump it into 3rd. With the towing package on this truck the temp rarely reaches 150 F, if you are driving sensibly.

Duck
05-02-2003, 07:44 PM
I solved my old duallys tranny problem this way -02 GMC Duramax/Allison. :D :D :D Duck

Duck
05-02-2003, 08:01 PM
Oh yea- I leave the OD off. Keeps the RPM's down and the torque can handle my boat weight easily.

Ziggy
05-21-2003, 02:23 PM
00 F350 powerstroker towing a 20.5 foot, Cruise control and OD for me most times unless I feel the TC kicking in/out. Engine torque(diesel) vs. HP(gas) for towing will win everytime.

Danhercules
05-21-2003, 04:49 PM
I got a 97 GMC 6.5L turbo Diesel. I tow a 18.5 jet in the summer and a 30' 5th wheel in the winter. I leave the cruise on in OD. When the tranny downshfts and I am on a hill, I take it down manually so it wont upshit back to OD until I am on to of the hill. Then I but it back to OD. I do this to keep it going in and out.
Thats my two Lincolns.
BTW, I have over 160k on my ORIGINAL tranny. eek!

Chase
05-22-2003, 12:33 PM
Just another note on this topic is preventative maintenace. I change the transmission oil once a year including a flush. I also change oil in the diff as well. Things will always work better and longer with a little TLC.

Foolish
06-26-2003, 11:42 PM
The only reason you want to lock out the OD is if your truck is constantly shifting in and out of OD. The real question is how much does your boat weigh and are you going up any hills/mountains. If your truck isn't hunting or constantly downshifting to get in a better power band (to get up that huge hill, or to keep up the speed you are going) you don't need to lock out OD. Heat kills transmissions, if you constantly shifting...you are generating heat. I would reccomend installing a transmission cooler and a transmission temp guage for added protection. wink

MagicMtnDan
06-29-2003, 05:16 PM
I'm on a Chevy Avalanche board a lot and this topic (Tow/Haul mode in a GM/Chevy product) has been covered a lot. Here's some info:
For what it's worth:
I Towed approximately 7,000 lbs of trailer & horses for around a thousand miles recently, through flat terrain & some rolling hills. I used the Tow/Haul mode the entire trip, but when pulling under 60, the transmission stayed in 3rd (related to engine rpm more than speed, I suspect - it seems to required ~2600 rpm in all gears before upshifting, although it's hard to know just what minimum is programmed into the computer). I spent a significant amount of time just over 60, pulling in OD as well. Outside temp was high 80's, A/C was on. Anyhow, the transmission temperature would run about the same either way, but I noted it was running significantly cooler on the highway, which I attribute to having the torque converter locked for significantly longer periods of time. From watching the temperature gauge, it looks like start/stop Towing puts a bigger load (thermal load, anyway) on the transmission. For what it's worth, I tend to "baby" the truck on starts with heavy loads, which tends to keep the trans temperature lower.
Also, in short, steep rolling hills, I'd take it off cruise & let the hill scrub speed off. Very minimal downshifting was required, compared to running with the cruise on. Minimizing shifts also let the transmission run cooler, by the way.
Bottom line: I'd leave the truck in OD, take it off cruise in rolling hills, and Tow on.
Two caveats (which should maybe go unsaid). First, my truck is a 2500, which obviously will two quite a bit differently than the 1500. Second, this is just my opinion & observations - take it for what it's worth. Click here to visit the Chevy Avalanche Fan Club board - click on Forums to see separate topics (http://www.chevyavalanchefanclub.com/)
[ June 29, 2003, 06:17 PM: Message edited by: MagicMtnDan ]

HotHallet
07-03-2003, 10:24 AM
You don't want the tranny hunting around! I would drop the truck in 3rd for climbing the hills and shift into OD when you are crusing down the freeway.

mtndewdrops
07-11-2003, 04:59 PM
For maintenence I like to have them drop the pan and change the filter instead of these "reverse flush" dealios. Unfortunately they probably don't drain the T/C.
Anybody have an opinion on that???