# gear selection while towing



## blacktail (Jun 6, 2013)

I've always heard it's bad for a transmission to tow a load while using overdrive in an automatic or 5th gear in a manual (if it's a 5-speed). My truck is a 5-speed manual and I'll be towing a small boat next week to a lake that's about 4 hours away. The boat is a 15ft aluminum and only weighs a few hundred pounds. Add in a small outboard and some gear and it's still not very heavy. The trailer probably weighs more than the boat.
I checked my owner's manual and it says not to use 5th gear while towing, but says this is recommended to maintain engine braking ability. It says nothing about damaging or straining the transmission.
My question is, would there be any risk to the tranny if I did use 5th? If it matters, my truck is geared fairly low and turns pretty high RPMs at highway speeds.
Really, with two mountain passes each way and lots of back roads, 5th gear wouldn't get used that much if I did choose to use it.


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## MasterMech (Jun 6, 2013)

Doubtful that you would hurt the trans at all.  The reason they make that recommendation is to avoid lugging the engine at low RPMs.  If you want to use 5th while cruising or down hills, that's fine.  But if you find yourself leaning on the throttle, pull it down a gear.

Engine braking improves in lower gears.  5th would provide the least amount of engine braking.


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## Highbeam (Jun 6, 2013)

Use all gears. That's why they are there. I tow in overdrive in a big diesel pickup with total weight at 16000#, the auto trans stays cool.

Another reason you may have heard that is that towing in overdrive can lead to lots of downshifts and upshifts, aka "hunting, and that can be very hard on a trans. If you can hold the gear then use it.


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## blacktail (Jun 6, 2013)

Thanks guys.


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## Jags (Jun 6, 2013)

Highbeam said:


> If you can hold the gear then use it.


 
Well said.


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## mikefrommaine (Jun 6, 2013)

My truck has a tow mode. Which keeps the truck from going into OD.


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## greg13 (Jun 6, 2013)

The damage usually happens to an automatic transmission, caused from either shifting gears from OD to high or overheated fluid. With a manual transmission YOU control the gear selection, the worst thing that happens is the engine lugs down in too high of a gear. You will hear if the engine is working too hard.


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## salecker (Jun 6, 2013)

Hi Blacktail
 In days of old.actually days of the GM TH700 you would fry the trany towing heavy loads in OD.
 I have a 03 GM 6.0 with auto,has the tow haul button,it tows in OD with the button in tow haul mode,it has a temp guage and i have towed heavy with it and it worked fine.
 Anything i have with manual trans,highest gear i can use for good RPM's.
 When you are towing/hauling heavy just up your vigalance while driving,watch your mirrors constantly and guages.
 I tow /haul heavy with pretty much any combination of trucks and trailers and havn't had any problems because i'm watching and listening all the time.Had a severly overloaded trip with my old 6.2/TH400 pulling a tandem trailer 200 miles,i went over the scales for curiosity the combined load was just a touch over 25K.Was a slow trip up the hills but never had a lick of trouble,and if i had to i would do the same trip with the same load,with the same truck.
 In fact i would use the old 6.2 diesel over the 6.0 gas for the heavy work anyday.
 Thomas


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## xman23 (Jun 7, 2013)

It doesn't sound like it's a big load. Just don't lug the engine. If you can accelerate, slowly from the speed your at. The gear your in is ok. If not shift down one gear.


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## Bigg_Redd (Jun 7, 2013)

What every one else said


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## Sprinter (Jun 8, 2013)

If you have a tach, I believe it's best to find the gear that allows your engine to run near it's peak torque rpm, which is a published spec.  That's supposed to give you best mileage while towing as well.


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## Highbeam (Jun 10, 2013)

Sprinter said:


> If you have a tach, I believe it's best to find the gear that allows your engine to run near it's peak torque rpm, which is a published spec. That's supposed to give you best mileage while towing as well.


 
It is generally best to be working the engine between the torque peak and the HP peak. Both published. What this does is give you a rising torque curve as you slow down when you hit a hill. If you're over the torque peak then as you slow down, the engine will make more torque and you should be able to maintain speed or at least have time to grab the next lower gear.


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## TMonter (Jun 10, 2013)

blacktail said:


> I've always heard it's bad for a transmission to tow a load while using overdrive in an automatic or 5th gear in a manual (if it's a 5-speed). My truck is a 5-speed manual and I'll be towing a small boat next week to a lake that's about 4 hours away. The boat is a 15ft aluminum and only weighs a few hundred pounds. Add in a small outboard and some gear and it's still not very heavy. The trailer probably weighs more than the boat.
> I checked my owner's manual and it says not to use 5th gear while towing, but says this is recommended to maintain engine braking ability. It says nothing about damaging or straining the transmission.
> My question is, would there be any risk to the tranny if I did use 5th? If it matters, my truck is geared fairly low and turns pretty high RPMs at highway speeds.
> Really, with two mountain passes each way and lots of back roads, 5th gear wouldn't get used that much if I did choose to use it.


 
I tow a 12ft Aluminum boat with my Corolla with no ill effects, I doubt your truck will have issues with something that small. I'd just gear down for long hills and you should be okay to use 5th on the flats or downhill.


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## blacktail (Jun 14, 2013)

I got home today and was pleased with my truck going over the passes. 5th gear was used a lot on flat and downhill sections. Once I hit the road it was easy to feel what the truck was comfortable with.
When I gassed up, it was a nice surprise to learn I got 18mpg going over the pass with a load.
It took me a long time to find the specific truck that I wanted and I've been 100% happy with it.


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