My tow/haul does not completely lock out OD, its just that it won't shift into OD unless you are flat and with almost no load. So, it will never shift into OD towing but will solo.
With the rpm's at only 3000 your just in high gear. So most likely you're kick down is from OD to high. What speed and rpm are you running before this happens and what is the truck/motor combo? As some have said tow/haul doesn't automatically lock out OD
Graybeard
02, 2500HD, ext, 4x4, sb, 8.1, allison, 3.73, TransFer Flow 50gal.
85 GMC, CC dually, 454, Gear Vendor OD
30'Layton TT
"When operating in
“TOW HAUL” mode, 5th gear (if equipped) is disabled
and 2-3 and 3-4 shift patterns are modified. Shifts into
Overdrive (4th gear) are allowed during steady cruise
(for improved fuel economy) and automatic closedthrottle
downshifts to 3rd gear are performed (for improved
braking) when driving conditions warrant. Pressing
the “TOW HAUL O/D OFF” button a second time to
select O/D OFF will disable 4th and 5th gear completely,
which should eliminate any excessive transmission shifting."
Quote: am towing my travel trailer with the "tow button" activated but my truck still feels like its continually kicking down. .. Can I assume its just the torque converter unlocking? And if so, is it bad for it to continually lock and unlock? There are no huge hill but every little incline in the road causes the converter to unlock, which increases the RPM's above 3000.. Then it locks back in again once I reach the top of the incline.. The Highway we take is full of small inclines so it is doing this continually and I'm lucky if it stays locked for a full mile.. Is this much locking/unlocking going to harm my trans or anything? I know it effects my gas mielage but thats not really a concern right now.
You didn't mention tow speeds, but over 3000 rpm is higher then just the converter unlocking at say 55-60...3rd gear with the converter unlocked should still be under 3,000 rpm...
"I won't camp next to you, if you don't camp next to me!"
2004 Titan King Cab, 2wd, 5.6L V-8, 5 Speed Auto Trans
Tow Package with killer 3.73 tow gears and TruTrac.
Bottom line is you dont have enough tow truck. You will be lucky to make your trip and still have a trans left. You need a 6000 liter motor with a 4.10 gearing in it minnimum . You need to be able to controle all gears of your trans. If I remember right the first year GM used the allison you couldnt lock out overdrive ( 5th gear). That setup wasnt worth a toot with the 8100 gasser. I think it was in 03 that GM changed that. Nothing wrong with these gasser motors. Yours is just too small with too fast gearing. Its hunting gears and that is what takes out the torque converter lockup clutch which in turn will trash the rest of the trans.
Like someone has mentioned, get a deisel and you will never look back. My choise is Dodge because it has a Commins industrial engine, second choise GM. Ford has a history of problems with there pickup deisel motors.
If you want to stick with gassers, a 6000 GM with 4.10 gearing and a trans that you can controll all gears will work fine. Or a 8100 with a 3.73 gear and the proper trans wiil give you more poop.
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