Tow Haul Dangerous????
Site Moderator
Joined: May 2008
Posts: 9,657
Likes: 24
From: Louisville, Ky
Ok here is the real deal on 5th gear.
Yes it is disabled in tow/Haul. I checked it on the highway this morning and again, this afternoon.
RESULTS with stock 275/60r20 tires and 3.92 gears MDS off.
65mph
Tow haul = 2000rpm
normal = 1800rpm
70mph
Tow/Haul = 2180
normal = 1950
There is not a big drop from 4th to 5th, but it is there.
Roughly a 200rpm drop.
Yes it is disabled in tow/Haul. I checked it on the highway this morning and again, this afternoon.
RESULTS with stock 275/60r20 tires and 3.92 gears MDS off.
65mph
Tow haul = 2000rpm
normal = 1800rpm
70mph
Tow/Haul = 2180
normal = 1950
There is not a big drop from 4th to 5th, but it is there.
Roughly a 200rpm drop.
Legend
Joined: Feb 2005
Posts: 8,058
Likes: 183
From: Fort Worth, TX
Ok here is the real deal on 5th gear.
Yes it is disabled in tow/Haul. I checked it on the highway this morning and again, this afternoon.
RESULTS with stock 275/60r20 tires and 3.92 gears MDS off.
65mph
Tow haul = 2000rpm
normal = 1800rpm
70mph
Tow/Haul = 2180
normal = 1950
There is not a big drop from 4th to 5th, but it is there.
Roughly a 200rpm drop.
Yes it is disabled in tow/Haul. I checked it on the highway this morning and again, this afternoon.
RESULTS with stock 275/60r20 tires and 3.92 gears MDS off.
65mph
Tow haul = 2000rpm
normal = 1800rpm
70mph
Tow/Haul = 2180
normal = 1950
There is not a big drop from 4th to 5th, but it is there.
Roughly a 200rpm drop.
2nd 1.67:1
2nd Prime 1.50:1
3rd 1.00:1
4th 0.75:1
5th 0.67:1
http://wahiduddin.net/calc/calc_speed_rpm.htm
2000 RPM @ 0.75:1 @ 3.92 @ 16.5" = 66.8 MPH
1800 RPM @ 0.69:1 @ 3.92 @ 16.5" = 65.3 MPH
2200 RPM @ 0.75:1 @ 3.92 @ 16.5" = 75.3 MPH
1950 RPM @ 0.69:1 @ 3.92 @ 16.5" = 70.8 MPH
Veteran
Joined: Jan 2007
Posts: 413
Likes: 1
From: Oklahoma City, OK
I was asking if my truck never enters 5th gear regardless of tow/haul. With tow/haul on, I am at 1800rpms at 70mph. With tow off I'm at 1800rpms at 70mph?????? That's why I said tow mode doesn't turn off 5th gear.
Maybe there's something wrong with my truck because there certainly isn't a 500rpm difference between the two while I'm on a flat no winded highway.
Maybe there's something wrong with my truck because there certainly isn't a 500rpm difference between the two while I'm on a flat no winded highway.
[edit] nevermind, it seems I'm late...
Site Moderator
Joined: May 2008
Posts: 9,657
Likes: 24
From: Louisville, Ky
Sounds like the transmission is throwing a code. Have the computer scanned. Sounds like a bad solenoid perhaps.
Shift points when in tow haul mode are delays from 2-3 and 3-4. 5th is disabled.
It will also downshift at highway speeds from 4th to 3rd when you touch the brake to help slow the truck.
Oh, by the way, welcome to the forum.
Shift points when in tow haul mode are delays from 2-3 and 3-4. 5th is disabled.
It will also downshift at highway speeds from 4th to 3rd when you touch the brake to help slow the truck.
Oh, by the way, welcome to the forum.