this could simply be my error, but I have noticed that when I shift up gears, my pick-up will almost always "jump", it is not at all smooth. The wierd thing is that I can competley realease the clutch pedal and be smooth, but the instant I put my foot back on the gas pedal, it jumps. My pick-up is a '94 F-350 with a 5spd and 7.3L IDI turbo diesel, any suggestions? should I simply work on a new technique or is this normall? Also are there any test that someone with very little mechanical knowledge could preform to find out if my cold start features and/or my turbo are working? The engine only has about 20-30000 miles on it, I'm guessing eerything should work pretty good. However it did burn out 3 glow plugs due to a bad controller, that made it a little hard to start.

Logan

 

Does it jump if you coast while in gear and then get back into the throttle? Could the jump be excess play in the drive train? What does it do if you shift without using the clutch? (it's hard to explain how to do this smoothly, but tap the throttle just as you start going into the higher gear and then apply power the instant it's fully in gear). Let us know.
As-an-aside-note
I was giving a test drive to a applicant last spring when after about 20 miles of him crashing and grinding gears I told him he needed a little more pratice and that I would drive the rest of the way. After he watched me shift without the clutch he proceeded to berate me for it since the driving school he had just grad-EE-ated from instructed that he never, ever shift without a clutch. Go figure.

alanscott

[link:ford-trucks.com/users/alanscott/|http://www.ford-trucks.net/users/alanscott/clubftesml.jpg]...Click!

 

You could be feeling the free play in the dual mass flywheel, however this is a typical response from owners of 7.3's with the Oe dual mass flywheel and clutch. It is not a smooth easy pedal.

 

[font size="1" color="#FF0000"]LAST EDITED ON 25-Mar-01 AT 04:32 PM (EST)[/font][p]alan, I have heard of "powershifting" but to me it doesn't sound like a good idea. I shift by pressing the clutch, moveing the shifter, releasing the clutch which increases the engine's RPMs, then pressing on the throttle. As I press on the throttle, the pick-up jumps once. How can I check if I have a dual-mass fly wheel? or is it guaranteed that I have a dmfw?

Logan

 

You have a dmfw if the clutch has never been changed by someone other than the dealer. Take off the inspection cover and you will be able to move the flywheel back and forth. You should have approx 5/8 free play. Anything over 3/4 and the flywheel is bad.

 

I agree, it sounds like your dual mass flywheel is about to crap out on you.

 

I don't know much about the truck and I'm not ready to take anything apart, I do know that the engine was replaced about 20000 miles ago and the truck has about 178000+/- miles. Today I went outon some of the poor quality back-roads after it rained yesterday for some 4wheeling, on the way back in a blue wire was spotted running from the cab about to the u-joint near the diff., I was less than half a mile from home, so I simply pulled the wire away and probbably will take it 30miles away to the nearest Ford dealer(my fav. part of country life, miles away from civilization, and yet I live "in town"). I'll see what I can find out.

Also, am I the only one who thinks the transfer case is confusing to shiftbetween 4hi, neutral, and 4lo? I plan to practice a little bit at that before I find myself stuck on a paved road with the transfer case in neutral. I am glad I won't have to use 4lo very often, creeping along at 5mph just aint fun.

Logan

 

>
>Also, am I the only one
>who thinks the transfer case
>is confusing to shiftbetween 4hi,
>neutral, and 4lo? I plan
>to practice a little bit
>at that before I find
>myself stuck on a paved
>road with the transfer case
>in neutral. I am glad
>I won't have to use
>4lo very often, creeping along
>at 5mph just aint fun.
>
>Logan

You should only shift between hi/lo or lo/hi while at a dead stop and the clutch disengaged. The transfer case is what transfers power to the front differential as well as having the capabilities of the low reduction final drive ratio. Although it is "part of your transmission", it is actually a seperate gear box.

alanscott

[link:ford-trucks.com/users/alanscott/|http://www.ford-trucks.net/users/alanscott/clubftesml.jpg]...Click!

 

Alan, everything you told me about the transfer case I already knew. The thing I find confusing is the shifting pattern used to shift between 4hi, neutral, and 4lo. I was simply asking if I was the only person who finds the pattern confusing, I know it would probbably be too hard to type out a description over the net of how to shift the transfer case.

Logan

 

Could it be a simple case of axlewrap??

-Jacksland

 

Actually, I'm begining to think the problem was more just my error, I think probbably just pushing the gas pedal too hard. I don't still see any good reason to have the dmfw checked. I eventually found out what the blue wire hanging near my axle was: a wire for a trailer brake controller, neither end was attached to anything so I know have that problem cured.

Logan

 

Could someone please define what axlewrap is? I've been hearing it for quite a while now and I have no idea what it is. Seems like it occurs on lifted trucks?

Thanks!
-Nick.

 

Axle wrap is the twisting of the axle in the upward position due to torque applied to the differential. Wheels turn forward, axle wants to rotate upward or "backwards".

Les

 

thats it right there, but in turn this twisting or turning of the axle bends all the leafs, shocks, driveshaft, all the way through. this is very bad, my lifted diesel had that problem till i fabbed up some traction bars one night i was drinkin, and now she works beautiful.

-Jacksland
God I Love Fords

 

I think that you are probably dealing with slop in the drivetrain, which many of these trucks have. I have a 460 and the ZF 5 speed and so I don't have a dual mass flywheel. My truck seems to have more slop in the drivetrain (even when it was brand new) than any other vehicle I have driven. Just letting off the throttle in the lower gears often causes quite a bit of jerking as the drivetrain components slop around. It makes shifting the vehicle smoothly more challenging as you have to do your best to get the drivetrain to a "float" condition before depressing the clutch pedal and you have to match the speeds fairly closely before releasing the clutch pedal. I think that this is just an annoying characteristic of Ford Truck's with ZF transmissions. I know one of the 4x4 magazines I get mentioned excessive drivetrain slop in the transmission when they tested an F-250 with a V10 and a ZF 5 speed. A friend of mine had a Dodge with the V10 and an NV4500 5 speed and it seemed like that transmission was very tight and quiet compared to mine. He drove mine and said that it was "much more loosey goosey" than his. I also read when GM was developing the new HDs that they were going to put the same ZF 6 speed behind the 8.1L and the Duramax that was behind the Powerstroke, but that they would be giving the transmission a "thorough going through to improve shift quality". In summary I think that ZF transmissions seem to be fairly durable but they have some annoying characteristics such as hard shifting and excessive rotational slop that will lose you style points.