Towing in OD?

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Rather than add to Jan-O's post about sway bars and tranny coolers I wanted to ask about a comment Colin made in regard to towing in over drive. I have a 98 Tahoe and 16" casita. A friend at the dealership, who also owns a Tahoe and pulls a large boat, told me to never pull anything in over drive. So ... I don't most of the time, in spite of the lower gas mileage, but it seems to pull fine when I forget. He assures me it's really rough on the transmission though. Any thoughts?
Lanny

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Lanny,
I read my owners manual to our Nissan Quest. It recommended NOT to tow in overdrive. I decided to follow its advice. Apparrently overdrive is a weak gear which is designed only for fuel efficiency once at a high rate of speed. I would rather not risk loosing it for the sake of a couple of miles a gallon....Actually, last time we took the Scamp out (a couple of weeks ago), I turned the OD off and re-checked the gas mileage. I was surprised to find that the milage was the same, or even better. Maybe because of the lack of constant shifting between gears.
Thats my 2 cents worth.
Maybe someone else will be able to explain better.

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Hi
I Have A 5 speed stick shift.I was told not to tow in OD/5th gear as it is the smallest gear in trany.I was asured it would break sooner or latter if towing in this gear.:wave

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Don't! :o

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Lanny, check your owner's manual. It will tell you.

Does your '98 have a tow/haul button? If you do, your manual will probably (check it for sure) tell you to use the tow/haul button with OD.

My husband has a '01 GMC Sierra Ext Cab. He has the tow/haul and the above is recommended.

I have an '02 Envoy and it says NEVER tow in OD. Always in third and that's what I do.

BTW, his 96 GMC did not have a tow/haul button and it said to use 3rd which he did.

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Thanks all for the quick reply.

Suz, there's the rub. I bought the Tahoe off E-Bay. Yep really. That sounds riskier than it actually was. The guy lived less than an hour from me so I could go see it first.

In any event, it didn't and doesn't have an owners manual. That's why I was asking the friend at the dealership. When I read where Colin said his manual said to drive in OD I wondered if my friend was just being conservative.

Adrain, you know, I never checked the gas mileage. I just assumed it would be worse. That's encouraging!
Lanny

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Lanny, does your Tahoe have a Tow/Haul button? If so, then you can use overdrive, if not then I would go with third.

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Howdy, Well I went outside and got two owner manuals. One is for my 90 GM 1500 and says that towing in OD is fine up to a trailer weght of 4000 lbs. The other one for my 2000 GM 1500 there is no weight restriction and only to shift to 3 rd if the tranny is hunting too often e.g. Hilly country or heavy loads. "Too often" is not defined as to frequency.. Also recommend the tow/haul mode for heavy loads or heavy large trailers. Also weights are not defined. Tow/haul is most effective when vehicle and trailer are at least 75% of the GCWR. I use tow/haul to tow my 13 ft Boler in hilly country and noticed that it won`t down shift as quick if at all on gradual grades. So going by the above I tow in OD because GM says so...It won`t affect warranty if it is in the manual and if towing in OD was a problem They would sure ban doing it because of warranty costs. Also if you have a manual trans they say it`s better not to use fifth gear but tow in 4 th with a trailer. So there you have it. I would suggest, on the Tahoe, see your GM dealer....Benny

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What axle ratio you got and what size tires? I got a 98 K1500 so we are almost identical.

The 98s did not have a tow button IIRC. In any event, having a button or not is not the end all answer on weather its OK to tow in OD or not (IMHO).

Ask a dealer if they have a manual in one of their used vehicles that they will let you read.

Rich

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You can download the owners manual for your vehicle at www.my.gmlink.com.

I have a 99 Suburban, the manual says to tow in overdrive, except when the transmission is force to hunt. The excessive shifting can allow heat buildup in the transmission.

Hope this helps.
v/r

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Hi Mike B.

Welcome to the group! Hey, I couldn't find the download spot for auto manuals. Can you give more details? Lots of good information at the site (lots of pop-up display ads, too!) ... but where are the manuals?

I was just about to post that my 2001 Suburban manual says to tow in overdrive.

Interestingly enough, the "tow/haul" mode (which resets shift points and RPM's) shouldn't be used ... because the extremely light weight of our fiberglass wonder isn't considered enough weight to qualify.

Also always good to hear from another Suburban owner!

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i tryed that GM link you posted and it just pulled up another search page ? could you check it again i would like to look up an maual for an older chevy pu .thanks
Al

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Oh-oh..............

The folks with 'real tow vehicles' are gonna mix up the statistics in this poll.

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I'll revise my "Don't" reply to 'towing in overdrive' to something like looking at the menu for prices in a high class restraurant......

"If ya gotta ask, ya probably shouldn't." :)

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:wave Hi Don.
and interesting subject to me. will now show my lack of attention to little details like this.
we picked up our casita near huston, pulled it back home via rice and the continental devide, thence to washington and back, yuma via san diego and back, san diego again and back via lake casita, to just south of vancouver,bc and back, thence to lake lopez and on the way home the trannie started bucking on a long grade. stopped at a toyota dealer in salinas and the first thing the service manger ask me was, was i "towing in overdrive?" in all this time had never thought about it. it had towed nicely all those miles without a hitch and all of a sudden it started complaining.
we now go into od when it starts to downshift.:o

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Interesting tidbit from the 'ATS website' regarding rebuilt Dodge ram transmissions.....

"Our high performance rebuilt transmissions are built to handle heavy loads and high horsepower. We increase the number of overdrive direct clutches from 8-10 to increases the amount of torque the overdrive can handle from 640 foot pounds to 800 foot pounds. We also increase the number of high/reverse clutches from 4-5 to handle higher torque loads. Better oiling to the overdrive planetary gears enabling towing in overdrive......

......Our transmissions are designed to enable towing in overdrive."

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At the library, I found information in "Mitchels" referring to my Chrysler mini-van 4 speed automatic transmission. As I understand it, when in overdrive, the electronic controls sense when the vehicle becomes 'under load' and 'unlocks' the torque converter in order to allow a smooth downshift. If it's not enough load to complete the downshift, the transmission might operate with the converter 'unlocked'. Interpreted as 'not good'.

I experimented with towing in overdrive on a flat interstate and would notice an increase of engine rpm on overpasses with out any speed increase. This was puzzling. But apparently the converter was becoming 'unlocked' during this time.

Trucks and cars are designed differently from the ground up....well, we know that?! :)

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Lou:

Keep smilin'........just part of the expense of having what sounds like a wonderful trip.

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Hi PineConeDon
What you read is exactly what our Ford Mechanic friend told us. When towing in OD the torque converter is constantly locking and unlocking which burns out the trany.

We towed our tent trailer for years in OD and noticed nothing different. The 17' stick built was what we noticed the constant lock/unlocking with. The 13' Trillium seems not to cause the problem but its not worth the risk.
Nancy

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PineConeDon: You quoted a website that was talking about rebuilt trannies. Everybody is trying to avoid that but if it does come around to a rebuild, beefing up a trannie is common. The guy I know that does it wont rebuild a 700r4 to factory specs, its only a couple of bucks to put in a better clutch pack and make a few other mods. Just make sure the guy doing the work knows you tow, how much it weighs, you will get you a slightly different rebuild.

The 4L60e in not a known to be extremly strong but it will do fine under reasonable conditions and even better once beefed up a bit. Im confident in mine, driving in OD and all but I would know when to drop it down and keep it there (I hope-where is that wood-knock, knock).

Rich

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All, (Al and Charles in particular)
Sorry for the sloppy homework in my previous post. The procedure for accessing gm's manuals online follows:

1. Go to www.gm.com, click on "Owner Center" in the upper right corner of the page.

2. This brings up a login page for the "Owner Center." Click on the "register" button, about mid-page in the graphics

3. Complete the registration process, it will ask you for the VIN, or year, make, and model, among other things. It will also ask you for an email address. They will email you your password to the email address you provide.

4. There will be a shortcut to the login page in the email that provides your password; go to the login page and enter the username and password provided. Once you login into the site, go to the "glovebox, " this is where you can download an electronic version of your manual, or order a print version.

I don't know how many model years in the past they service on the site this way. I hope this helps and is more complete than my last post.
v/r
MB

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Hi All
As I said in Gen Chat my wife and I bought a new to us tow vehical.Of course this is first auto trany I have had in 25 years.Now I have got to see what I can do according to manual.In trailer towing section, NOTHING said about towing in OD one way or the other.

In another section of manual for one paragraph,which I all most missed Says (When driving in hilly areas,towing a trailer or carring heavy loads TURN OD OFF)This will reduce trany failure.

If that isn't clear to me nothing is.
;)