5th Gear Lockout

[CLB]

Hello,

I'm a bit of a Newbie so not sure this post is in the right section. I have a 2005 F250 4x4 6.0L Auto and love the truck so far. My only complaint is when towing in hilly terrain it constantly hops between 5th and 4th gear in Tow/Haul mode (trailer is about 9000lbs with a large frontal area). In this terrain I would prefer to just have it stay in 4th.

Is there any way to lockout 5th gear so the transmission stays in 4th (1:1) or even 3rd overdrive (1.10:1)?? The gear selector only gives you the option of 3rd or OD.

I would love to somehow have this lockout hooked to one of the upfitter switces.

Any help is appreciated!

Thanks.

[1snakedoc]

in not sure on the 6.0 but i think they only have 4 gears.

[CLB]

5R110 TorqShift trans was mated to the 6.0. It is advertised as a 5 speed auto but actually has 6 gear ratios. As I understand it uses 3rd+OD instead of 4th when ambient temps are cold. Either way 5th is OD and 4th is either 1:1 or 1.1:1 depending on ambeint temps. I want to be able to lockout 5th and keep it in 4th!

[colo_dually]

The only way you are going to be able to hold effective 4th gear, is to have a tow file written not to see a 5th.

Here's my question though, what RPM's and Boost levels are you seeing, and how much are you pulling that make you want to eliminate 5th gear?

Reason I ask, is depending on speed, gearing, and load, you may be taking the motor further from the peak power/torque band and do more harm than good.