2005 GMC 5.3 Liter Towing

[rockfordroo]

It's a 4 speed. D-3-2-1. Tow/Haul button. No other buttons.

Also checked 2015 Silverado manual. No "overdrive," "over drive" or "OD." At least GM doesn't seem to know/use the term overdrive.

Overdrive is really just a concept, anyway. The engine really doesn't have a clue how fast the output of the tranny is turning. It only knows what the load is.

The accurate statement is probably "drop a gear." Your truck may not really have "overdrive" anyway.

[ov845]

Does it look like this?



"D" represents 3 forward gears plus Overdrive
"3" is just the 3 forward gears

[Mr Havercamp]

Put it in D and go, use the tow haul only when in hill country or towing something heavy. if you get in a situation where its lugging or seems to be hunting drop it to 3. Its a 4L80E. Prior to 91 or 90 it would of been a 4L60E and they actually called it overdrive. That's all if I am remembering my numbers and years correctly.

I've had all of em, never worried about the overdrive crap, and never lost a tranny.

[rockfordroo]

Originally Posted by ov845

Does it look like this?

Attachment 98562

"D" represents 3 forward gears plus Overdrive
"3" is just the 3 forward gears

Yeah, looks more or less like that. That's why I think folks saying "turn off OD" are being confusing to many of us. (Me, at least.)

[ov845]

Originally Posted by rockfordroo

Yeah, looks like that. That's why I think folks saying "turn off OD" are being confusing to many of us. (Me, at least.)

Roo

What Mr Havercamp is saying is correct. Technically "OD" is electronically controlled turning it off/on is correct via a button or moving the gear selector to a different selection.

[rockfordroo]

Originally Posted by ov845

Roo

What Mr Havercamp is saying is correct. Technically "OD" is electronically controlled turning it off/on is correct via a button or moving the gear selector to a different selection.

Checked 2015 F-150 Owners Manual:

Drive (D)
Drive (D) is the normal driving position for the best fuel economy. The overdrive function allows automatic upshifts and downshifts through gears one through six.

Discusses an "overdrive function."

Later it says:

Descend a hill in the same gear you would use to climb up the hill to avoid excessive brake application and brake overheating. Do not descend in neutral. Disengage overdrive or move the transmission selector lever to a lower gear.

That's all. Never says HOW to "disengage overdrive" but implies there's another way besides moving the selector to a different gear.

The 2014 Ram 1500 manual does explain overdrive a lot better, but again, doesn't discuss "turning it off." It does discuss a manual mode where you "limit the highest available gear." Also says if you turn on tow/haul, it won't go into overdrive (i.e., limits the highest available gear.)

But again, none of them ever say "turn off overdrive." So my point is that we probably shouldn't either. Just say, "drop it down a gear" or "turn on tow/haul."

[The_Rhino]

My truck is a 2005 GMC 5.3 Liter V8 engine Sierra short bed 4x4

OP: Unfortunately the GMC 5.3 doesn't have a lot of torque & the tranny doesn't help... IMO changing rear-ends, etc. will not solve your problems...

In comparison, Ram got it right with the affordable 5.7 Hemi which produces lots of torque for a gas engine. In 2013 I bought a 2011 Ram 2500 CC w/5.7 Hemi for only $14K and it has towed my 8,500 TT through the Smoky Mts. with power to spare. So for the price of Band-Aide fixes you could probably sell your GMC & buy a Ram... (Or get a GMC with a bigger engine, but it will cost more than a Ram...)

[Mr Havercamp]

Roo, Dont worry about any of that Ford and Dodge foolishness, Neither one knows how to design a transmission, GM does. Just put it in D and run the hell out of it.

[Platokidd]

CoopsRvn, Would recommend a tranny cooler and they are easy to install yourself.
Plenty of you-tube videos on the install.

If the tranny is constantly shifting from D to 3, I would just leave it in 3 and use the towhaul option. Sometimes just slowing down a few mph will help find the sweet spot for the truck.

[terryallan]

Originally Posted by rockfordroo

I see "turn off OD" a lot on this forum. But my Owners Manual doesn't even contain the word "overdrive" or "over drive," let alone talk about turning it "off."

What I think you mean is take it out of Drive and put it in the next lower gear, as my Owners Manual says:

D (Drive) can be used when towing a trailer, carrying a
heavy load, driving on steep hills, or for off-road
driving. You might want to shift the transmission to a
lower gear selection if the transmission shifts too often.

I know as a new truck owner a couple of years ago, this was very confusing for me for awhile. Does ANY truck have a switch that "turns off overdrive?"

Fords do. Mine does anyway

[Tommy Joann]

Originally Posted by The_Rhino

OP: Unfortunately the GMC 5.3 doesn't have a lot of torque & the tranny doesn't help...

The new 5.3L V-8 is SAE-certified at 355 horsepower (250 kW) and 383 lb.-ft. of torque (519 Nm). With EPA-estimated fuel economy of 23 mpg highway (2WD), it offers the best fuel economy of any V-8 pickup, and beats the fuel economy estimates of the Ford EcoBoost V-6.


Read more: GM 5.3 Liter V8 EcoTec3 L83 Engine Info, Power, Specs, Wiki | GM Authority

[CoopsRvn]

Platokidd, I have some county hills I can take it on to get the feel of it.

[The_Rhino]

The NEW 5.3L V-8 is... 355 horsepower and 383 lb.-ft. of torque...

Exactly. I was referring to the OP's older 2005 5.3L w/310hp & only 338lb.-ft. of torque. It's a real dog towing...

The OP just bought a new TT so he may not be able to run right out and buy a new/newer GMC. In 2013 I bought a 2011 Ram 2500 CC for $14K and the 5.7 Hemi has 383hp & 400lb.-ft. of torque. IMO the OP could sell his 2005 GMC & buy a 2011+ Ram 2500 without breaking the bank... The GMCs hold their value & the Rams offer the best bang/buck...