E40D TC Lock/Unlock question

[iverger]

My torque converter works fine during upshifts but I don't think it is acting right when coasting. No matter how fast I'm traveling the TC always unlocks when I lift of the pedal. Just touch it slightly and it re-engages and starts slowing me down.

I have found threads that tell me that this function is somehow affected by the brake lights but where and what? Should I be looking for a switch or sending unit somewhere that needs replacing?

Thanks,
Bob

 

[david85]

I've never run an E4OD bone stock with the factory controller, but I think what you are describing is normal.

 

[rjjp]

Yea, it is normal, when coasting the E4OD unlocks according to all data (a computerized maint. manual) and everyone I know that runs them does the same thing, including me.

 

[LCAM-01XA]

Unfortunately that is indeed the norm for them, apparently someone at Ford thought that the fuel savings while coasting are worth more to the driver than engine braking capability. For this reason downshifting into 3rd while descending a hill will usually do you no good for holding your speed - with factory-set E4OD 2nd gear is what you need for this, even with an empty truck, but you have to watch out to not over-rev the engine.

 

[argve]

Yep the tc unlocks when you let off the go pedal. As stated it was done for fuel savings. If you want to keep it locked you can just press ever so slightly on the go pedal and it will lock up to gain some engine braking (what little there is - meaning we have no throttle plate so you won't create a vacuum for the engine work against).

 

[LCAM-01XA]

Actually engine braking with a diesel is much higher than that of a gasser engine - the reason is that the compression ratio in the cylinders is much higher for the diesel, and it is that compression the driveline is working against. 3rd gear with the converter locked can hold an empty truck back down some 8-10% grades, 2nd gear (converter unlocked, works better that way) will hold a loaded 1-ton, and if you are idling against the high-speed governor in 1st gear you can have a trailer behind you and you still won't need to touch the brakes. At least this has been my experience with my 7.3 IDI truck with 4.10 gears and E4OD with manual converter lockup.

 

[iverger]

Thanks all. I guess I'm glad to know it is working correctly, just not the way I would have preferred.

Thanks again,
Bob

 

[sootman73]

Yea theres a lot of things that i dont prefer that the E4OD would do but with a stock computer there is nothing you can do about it... if you want to i have been talking to david85 about his Baumann controller and by the sounds of it is very happy with how he can control the trans and change the shift points vs. engine load.... someday i'll get one but im moving into my own place so that got put on hold rather quickly....

 

[Fozz]

As stated, anytime you're off the gas or on the brakes, it unlocks. Do a search on the lock-up mod for this tranny. I did it and am very happy, especially going downhill with my 5r in tow. Plus with it unlocked, driving around town is a lot nicer. I almost bought a Transgo Tugger shift kit, but now I'm satisfied with how the tranny is performing.