Hey guys, I have a quick question ... looking in the owner's manual, I see that if my truck had an E40D instead of the 5-speed, its GCWR goes up from 14,000 to 17,000 pounds. What's the weak link in the chain here? Is the trans fragile, or is this just because the auto benefits from the torque converter? Seems like a big spread in weight capacities ...

Cheers!

--Finn John (90 F250 XLT/L, 5sp, std cab, 4.10s, 4x4, 444 "IH Inside")
Corvallis/Albany, Ore.

 

I think the reasoning between auto Vs stick for towing, is partly the torque converter, but the E4OD is also rated for towing in top gear (overdrive), and the 5 speed is not (or so I've heard).

The reality is different however, since there is a much higher failure rate among the E4s than the ZFs, even more so in the early years.

The E4OD can go to hell and back if properly built, but even the latest OEM setups leave alot to be desired.

My feeling is that the difference in rating has more to do with the skill needed to operate a manual transmission while towing, than any durability conserns, lets face it, you don't have to think much when the transmission does it's own shfting.

 

Also don't forget all the trucks with the ZF 5 had dual mass flywheels from the factory.

That was another less than desirable setup.

 

What the heck's a dual-mass flywheel?

 

A dual mass flywheel is a two piece flywheel.
There are dampening springs between the two pieces.

The thought was that would help dampen the diesel power pulse as each cylinder fires.

Most trucks that never see heavy loads don't have much problem with them, but they are expensive to replace.
The shop spec for replacing the dual mass flywheel is when there is more than 5/8" free travel between the flywheel pieces.

 

I never understood there thinking for dual mass flywheels large trucks never had them.
more bucks for clutch jobs can be eliminated

 

if you buy the solid flywheel setup you can do away with that and make it more reliable. i still have the dual mass on my diesel with the zf and ive had no problems yet. i at one time i thought of converting to the e40d, but after all the problems ive heard i think ill just keep what i have then i wont have to deal with all the problems that can come along with the automatic

 

better fuel mileage with zf witch counts more and more everyday to me I dont mind shifting nearly as much as I used to.

 

The large trucks also have much larger driveline components so the power pulses have less effect.