Tow haul and overdrive

Bedlam wrote:
You were told wrong.

I should have added when towing at let's say 60.

My 68RFE would tow at 60 in 6th all day with 3.42's on flat ground with tH and EB engaged.

MeAgain???

Cummins12V98 wrote:

Bedlam wrote:
You were told wrong.

I should have added when towing at let's say 60.

My 68RFE would tow at 60 in 6th all day with 3.42's on flat ground with tH and EB engaged.

MeAgain???

My Aisin with 3.42's will not shift into 6th until 65mph but once it's there I can back down to 60 in 6th. If it downshifts to pull a grade then it will not go back to 6th until 65. I'm sure it's rpm and load related but 65 is the magic number to get 6th with TH on. 5th is 55mph. It will run in 4th until 55 with TH on. This relates to 2000 RPM.

Unless I'm running interstate I always lock 6th out towing my rig. There are times I will lock 5th out in the rolling backroads.

SoundGuy wrote:

gmc6000 wrote:
No, tow/haul does not lock out overdrive on any GM or Ram truck, at least. Tow/haul only changes your shift points on the transmission.

I guess it depends on what one means by "overdrive" but I recently bought a 6-spd 2012 Silverado 1500 to replace our 2005 4-spd Avalanche for towing and in Drive when I engage Tow/Haul it absolutely does lock out 6th gear. If I disengage Tow/Haul while towing at highway speed and happen across a relatively flat section of road only then will the transmission upshift to 6th, otherwise with Tow/Haul engaged the highest it will go is 5th, which as it turns out is right where it needs to be - 2000 rpm in 5th, downshifting occasionally to 4th as road conditions may require.

You may want to try this unloaded: Get the vehicle over 100 kph and then engage tow/haul. If it does not downshift, your top gear is not locked out. If it does not go into top gear while towing, your vehicle may not be developing sufficient power at that speed to sustain 6th gear.

No way to lock out O/D with my 2010 5.4L F250. 5spd Torqshift.

The Op is talking apples and most are talking oranges.
Shifting parameters/clutch locking and unlocking parameters/OD or no OD/the whole tow/haul event depends on the trucks transmission size/year model.

The 6L80e in the wifes 2016 1500 chevy 5.3 (and her old same chevy truck in a '06 5.3 4L60e) has a completely different tow haul operation than my sons 2016 2500 chevy Dmax/A crew cab.

All the tow/haul does in the 1500 '06 and '16 truck is hold the TC clutch unlocked to a higher rpm while accelerating. In fact the TC clutch is still unlocked while going downhill at that rpm/speed. At certain speeds/rpm there is no engine braking simply because the TC clutch is unlocked. Thats why I stopped using T/H mode in both trucks. Neither truck T/H mode locked out OD.

My sons '16 Dmax/A tow/haul works completely different and does a really good job all around.

Cummins12V98 wrote:
From what I have been told tow haul will not allow use of 6th with the AISIN trans.

MeAgain what say you???

Your signature shows you have a Ram with the Aisin transmission.

You also have stated several times in other posts how much better the Aisin is than the Allison.

Confused that you do not know how your transmission works.

RCMAN46 wrote:

Cummins12V98 wrote:
From what I have been told tow haul will not allow use of 6th with the AISIN trans.

MeAgain what say you???

Your signature shows you have a Ram with the Aisin transmission.

You also have stated several times in other posts how much better the Aisin is than the Allison.

Confused that you do not know how your transmission works.

Lol, so true. Must be lack of geritol day.
But fwiw, 12V qualified it with a certain speed limit in mind. Either way, there are a lot of recent posts that if the posters actually read what they said, they would think about having their blood sugar checked because somethin ain't right around here recently!

RCMAN46 wrote:

Cummins12V98 wrote:
From what I have been told tow haul will not allow use of 6th with the AISIN trans.

MeAgain what say you???

Your signature shows you have a Ram with the Aisin transmission.

You also have stated several times in other posts how much better the Aisin is than the Allison.

Confused that you do not know how your transmission works.

MeAgain has the 3.42 gears, I have 4.10's. In 6th I am 1,750 rpm's and he is the same in 5th. I am wanting a confirmation from what I "remember" he said about his staying in 5th towing at the upper limits of his trucks ratings while in TH.

Not sure what I have said about the Allison has to do with this???

"But fwiw, 12V qualified it with a certain speed limit in mind."

Thanks, yes I agree people should read what is actually SAID not what they think someone said because of a bias. Personally I try to read my posts before hitting submit and also after it's posted.

Also quotes without the context is very misleading.

I do appreciate being told when I am wrong, not from opinion but fact or actual experience. That's how we all learn.

2016 Silverado 1500 does not lock out any gears in tow haul.