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Tow / Haul Mode Questions

Chevrolet1

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Chevrolet1 Enthusiast

Chevrolet1

Posted
Posted

Have a 2005 Silverado crew cab with 5.3L, 3.23 gear and factory towing package (love it). Towing my 2,800 lb. camper + family + gear for the first time was very easy, but it seemed to occassionally go into overdrive and I want to know if that's they way it's designed. My total load (camper, family and gear) was 4,000 pounds at the absolute most and based on pessimistic meaurements.

 

When towing the camper at 60 mph for a while on a relatively flat road, the tach would sometimes drop to 1500-1600 rpms. Then when I encountered a large enough incline, the tach went to 2,100 rpms and the trans downshifted. If I kept it below 60 mph (i.e. 50 - 55) on a flat road, it seemed to stay right around 2000 rpms (in a lower trans gear). I know I pressed the tow/haul button and that the dash light was illuminated. And the lower trans gear shift points did seem higher (which I expected).

 

Is overdrive occassionally engaging? Should it be engaging at all?

Does anyone have the techincal specs and details of the tow/haul mode behavior (e.g. trans shift point changes, etc.).

MikeNH Senior Enthusiast

MikeNH

Posted
Posted

Overdrive is not locked out in T/H mode so yes, it likely did shift to 4th a few times. If you don't want that you need to put the shifter into 3rd. T/H will raise shift points and firmness as well as downshift easier I think.

ChevyTech77 Senior Enthusiast

ChevyTech77

Posted
Posted

I would never haul/tow anything over 1,000 lbs in a 4L60E transmission equipped truck, like that listed here in this thread, IN O/D. T/H will do nothing more than just raise the transmission shift points, it will NOT lock O/D out and if you tow over 1000lbs with a 4L60E trans IN O/D, you're just asking for trouble, imo. Seen them smoked too many times from towing in O/D.

Chevrolet1 Enthusiast

Chevrolet1

Posted
  • Author
Posted

Thanks guys, this confirmed my thoughts that OD had engaged a few times. Just wanted to confirm since my manual didn't state whether or not it locked out OD (which is what I heard from other people).

 

I personally believe that towing should not be done in OD (too much shifting --> too much heat) and will definitely be using "3" going forward. Fortunately this was a relatively short trip that was well under my towing limit and had only a few small hills, plus I let all but one hill decelerate me to prevent downshifts. The trans fluid was recently flushed, but I'll be checking it this weekend for peace of mind.

  • 3 months later...
00Silverado4x4 Senior Enthusiast

00Silverado4x4

Posted
Posted
I would never haul/tow anything over 1,000 lbs in a 4L60E transmission equipped truck, like that listed here in this thread, IN O/D. T/H will do nothing more than just raise the transmission shift points, it will NOT lock O/D out and if you tow over 1000lbs with a 4L60E trans IN O/D, you're just asking for trouble, imo. Seen them smoked too many times from towing in O/D.

 

 

1000lbs? Really? The 4L60e can handle more than that all day long. I've used mine to tow my travel trailer 4200lbs loaded, bed full & 5 people in the truck on a 6300 mile track from Alaska to Georgia with no problems. I now have 87k+ miles. Agreed the more weight you add the slower you go & select lower gear.

I always use tow/haul when loaded but 1000lbs will not kill this transmission.

tyhuck Senior Enthusiast

tyhuck

Posted
Posted

It depends on the terrain. If Im on flat ground, like near the SETX coast, Ide have no problem towing anything that the truck could handle all day long in OD. However, where I live it gets hilly, so I prefer to tow in 3rd if the weight gets rather large. Just depends on how much "hunting" the trans is doing.

jtstacy77 Enthusiast

jtstacy77

Posted
Posted
I would never haul/tow anything over 1,000 lbs in a 4L60E transmission equipped truck, like that listed here in this thread, IN O/D. T/H will do nothing more than just raise the transmission shift points, it will NOT lock O/D out and if you tow over 1000lbs with a 4L60E trans IN O/D, you're just asking for trouble, imo. Seen them smoked too many times from towing in O/D.

 

 

1000lbs? Really? The 4L60e can handle more than that all day long. I've used mine to tow my travel trailer 4200lbs loaded, bed full & 5 people in the truck on a 6300 mile track from Alaska to Georgia with no problems. I now have 87k+ miles. Agreed the more weight you add the slower you go & select lower gear.

I always use tow/haul when loaded but 1000lbs will not kill this transmission.

 

 

:P I used to tow my 4100 lb pontoon and trailer at least once a weekend in the summer (before I leased a slip) and never had any transmission trouble. Not sure it helped my castech heads though!

wavery Enthusiast

wavery

Posted
Posted

I tow my 4,000# trailer (and about 800# of stuff in the back) a lot, almost every other weekend. I also pull it in the High Sierras to Bridgeport and back about 4 times a year. We tow in altitudes of over 8,000'.

 

I have the same ratio (3.23) but the smaller (4.8) V8. I have a large trans cooler with a pusher fan and I run synthetic trans fluid. I have a ScanGauge in my truck and I've never seen trans temps over 200*, even pulling the Grape Vine in 115* weather.

 

I've had absolutely no issues with my trans. I always tow in 3rd/tow mode.

Diesail Enthusiast

Diesail

Posted
Posted
It depends on the terrain. If Im on flat ground, like near the SETX coast, Ide have no problem towing anything that the truck could handle all day long in OD. However, where I live it gets hilly, so I prefer to tow in 3rd if the weight gets rather large. Just depends on how much "hunting" the trans is doing.

 

^X2, if it is hunting bump it down a gear.

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