# chevy will not stay into over drive



## peter1 (Feb 17, 2004)

Hi guys

I have a 2002 Chevy Tahoe that can pull 7700 lbs. and Iâ€™m pulling a 28bhs.. I have taken a few trips with this setup but I noticed most of the time Iâ€™m driving and trying to maintain 60 mph most of the time the truck will not go into overdrive.. Have you guys ever experienced this before and can something be done to help keep the truck in overdrive..Thanks for any input in advance

Pete action


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## camping479 (Aug 27, 2003)

Hi Pete,

Do you know which engine and rear end gearing you have? Also do you have the towing package?

Most of us with the 5.3 vortec powertrain tow in 3rd with the tow/haul on. I found in overdrive, the slightest incline would shift the trans out of overdrive into third. A lot of shifting leads to a build up of heat which you want to avoid.

This link was a thread recently on towing in overdrive you might want to check out.

http://www.outbackers.com/forums/index.php?showtopic=620

Mike


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## fixjet (Jan 19, 2004)

Just forget 4th gear (overdrive). It ain't gonna happen with small block. The only way to pull in 4th gear is to have a big block to handle the load. To try to use OD is to hard on the trans. Just because it is rated to pull "x" amount doesn't mean it will do it in OD. In the winter I pull a 5500 lb snowmobile enclosed trailer and we use 3rd gear also on my brothers 2500HD Chevy. It has instant MPG indication on the dash and there is less that 1 mpg difference in mileage from 3rd to 4th. I get the same results with my Suburban pulling the Outback or the Snowmoible trailer. The trans will run hotter in 4th also. The reason it runs hotter is because it is shifting from 4th. to 3rd. and from 4th gear lockup to just 4th gear. All of this shifting in and out of lockup and 3rd. to 4th. gear produces heat at every shift point because of the slight spillage during a shift. (normal) But if you shift constantly your cooling system can't keep up and your temp goes up. I tow only in 3rd. gear and very seldom every shift out. I just cruise along at 65 and it stays put in 3rd. It
's much easier on the truck.
Dan


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## aplvlykat (Jan 25, 2004)

I have to agree with the above comments. If you have the tow/haul mode button click it on and go







, forget about OD except on long flat roads with no head winds. Kirk


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## NDJollyMon (Aug 22, 2003)

Ditto.


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## MikeyM (Mar 24, 2004)

aplvlykat said:


> I have to agree with the above comments. If you have the tow/haul mode button click it on and go
> 
> 
> 
> ...


Werd!


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## NWcamper2 (Mar 28, 2004)

Okay I might just be having a blonde moment here but what is "Werd!" ?


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## Splash Mountainers (May 3, 2004)

We just picked up our 28 BH on Monday. We got to meet our first fellow Outbackers.com "and 4togo" while we were there. Great people!

I towed it home with our 2003 Tahoe Lt and didn't have any problems. I kept it in "D" most of the way and listened carefully to the engine for over shifting. At 60MPH it ran at ~1800rpms without strain. 3rd put me at ~2500rpms. I had to pull it over 2 lenghty 6% grades on my way home and I have some questions.

I tried to use 3rd up those grades to keep it at 60MPH and almost redlined the tach----I shifted to "D" and it pop in and pulled nice and smooth up the hills. I guess just listening to your TV and what its telling you is the best way to go. As conditions change so should your towing techniques...

Now, what should have I done up those grades?? Lower the speed and keep it in 3rd or use "D" and listen for overshifting? I don't want to make and tranny burning mistakes!!


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## Y-Guy (Jan 30, 2004)

I found with my Avalache (1500 5.3, 4.10) that just the tow/haul mode is all I needed to do most of the time to prevent the shifting. I kept my speed at around 60 on the open interstates and 55-50 on the Highways and it did just fine. On the steeper grades I'd shift down and drop my speed if needed. Trying to keep 60 on an incline maybe pushing your truck to far.


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## Splash Mountainers (May 3, 2004)

Ahhhh







so the tow/haul mode button controls the overshifting?? I wondered what exactly that did.

Cool...


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## hatcityhosehauler (Feb 13, 2004)

The tow/haul mode actually changes the shift points controled by the vehicles computer, to allow the engine to reach peak HP and torque RPM's, therefore allowing the vehicle to move that 5000#+ of TT behind you much easier.

It does come at a cost, lower MPG's, and increased tranny temps. If you don't have one already, a transmission temp gauge is a wise investment, as is an auxillary transmission oil cooler.

Good luck with the new Outback, and welcome to the forum.

Tim


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## jgerni (Nov 10, 2003)

My Suburban will rarely go into OD while towing the 25RS-S. With the Tow/Haul on it will go in after going past 60mph and very flat or a slight decline. It tows much better in 3rd and hums along nicely at 2600rpms with out trouble.

I have noticed that as soon as I hook the camper up the burb starts to consume oil though. In normal driving it consumes none. Has anyone else had this problem with the 5.3L? I am running Moble 1 Synthetic in the engine, transmission and diff.


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## camping479 (Aug 27, 2003)

I think it is normal for and engine under a heavier than normal load to use a little oil.

Mike


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## Jevi (May 28, 2004)

Had the same concerns with my 2002 Tahoe, 5.3L, 3.73. Try it without the trailer some time. In Tow/Haul, GM has reprogrammed the shift points on the transmission. Even without the trailer, it won't go into OD until you reach 60 mph. If you want to cruise along at 55 mph, it will never shift into OD. Of course, if you are on nice level running, you can disable T/H and let it shift. Switch T/H back on if it starts to strain or shift too often.


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