MT654 Lock up in 1st

[Jason O]

Has anyone tried to force a lock-up in 1st gear by powering the soleniod? I'm looking to maximize engine braking.

I have a steep hill to travel down any time I take the truck out. The ideal speed is right around where the converter unlocks in 2nd as engine speed drops, resulting in loss of engine braking. Then I speed up
a few MPH and it locks up again.

I was considering trying a momentary switch to power the solenoid and keep the converter locked. My driveway is even steeper, and 1st gear, converter locked would be ideal.

The biggest potential problems I see would be the 2-1 downshift would be so harsh, something would break if the converter was locked, and remembering to let off the solenoid when comming to a stop so the engine wouldnt stall.

Any thoughts?

 

[Nomadic]

I don't know the RPMs at the point it unlocks, but it sounds like a safety risk if it isn't done right. Say you needed to brake for a deer and the converter lock was overridden. Wouldn't the truck stall? Maybe wire a sensor from the brake to your auto-locking mech so the converter unlocks if you brake.

 

[Jeeperjoe]

Yeah and that was / is the big fear on these when the engine stalls due to hard braking you loose steering functionality and if I'm not mistaken there have been a few deaths due to that hence one of the reasons they installed ABS... awfully big truck to flop on its side / top

 

[Jason O]

I thinking of a momentary switch on the shifter that you would have to hold in by hand. Nothing automatic

 

[dmetalmiki]

When I read things like this, I (yet again) can not understand the 'wick' of designers who prepare a military tactical vehicle to not perform at least as well as 'other countries' military combat situation vehicles that Reverse in low range, Have ctis that actually works and is reliable. Do not have an assortment of 'gimmicky' electronics that constantly go wrong, Stop AND steer when you (have to!) brake in an emergency, Nor a plethora of other ridiculous 'problems'. They mostly ARE. mostly rough, tough, basic,reliable, and simply just preform as required. When required. (gripe over).

 

[Jeeperjoe]

I thinking of a momentary switch on the shifter that you would have to hold in by hand. Nothing automatic

That's ano intriguing idea I guess I would just be concerned that you could be locking it up to too low an rpm

 

[simp5782]

The transmission will not like it. You will run into issues powering up that solenoid. I moved my lockup to 3rd gear since i pull alot. You are better off using your roller on the brake valve to slow you down or add a manual brake caliper and rotor to the front output or rear output flanges

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