I have a 1990 f-250 4x4 5l with a zf-5 speed tranny. And back a couple months ago it started to vibrate int 4th and 5th gear sometimes it feels like a vibration sometimes it feels like a jerk. kinda like something is slippin here is what I think my possibilities are

clutch
suspension?
tires?

I do not know when the clutch was last replaced or if it has ever been replaced. Im the 3rd 17 year old its had and it was also a farm truck for 10yrs. I know I have worn out suspension and tires. The u-joints on the driveshaft seem to be prety good to me. I hear a slight wine from the transmission but it could just be me to. And its maily in 3rd, 4th, and 5th gear. my clutch has also gotton a bit softer as well. which is what me think its clutch related

Any suggestions would be great! Thanks Josh

 

When do you feel it? How many miles are on the truck?

 

Pull the inspection port on the bell housing, take a look at the clutch (check your Haynes). Is the pedal completing its full range of travel? And while you're at it, check the clutch fluid level. And as to when you feel it, we need RPM & MPH. Also what kind of vibration is it? The whole truck, the driveline, etc. Is it in those gears or above a certain speed or RPM. That will help us tell if you should start with the engine, Trans, clutch, wheel weights, etc.
-Mike

 

It seems to mainly be above 1500rpm in 3rd 4th and 5th gear. as far as speed my speedometer is broke and the only speed i know is 55 mph which is roughly 1500 rpm in 5th gear.
As far as clutch fluid level, you mean the slave cylinder? I already have topped it off but will check inspection port next time I go to my granpas (where the tools are lol)
As far as the shaking it mainly feels like its coming from the back of the truck.
there is also roughly im guessing 200,000 miles on it

There is to things I forgot to mention though i dont now if they matter sometimes when the engine is cold ill be goin down the road and suddenly loose all oil pressure, I put it ito neutral and restart it and pressure comes right back.

and also almost always after Ive driven somewhere and everything is warm I can be goin through a parking lot or driveway with clutch out in 1st gear idiling and hear almost kinda like a rachiting sound Ill try to record and post if ya'll want? kinda hard to describe

 

It seems to mainly be above 1500rpm in 3rd 4th and 5th gear. as far as speed my speedometer is broke and the only speed i know is 55 mph which is roughly 1500 rpm in 5th gear.
As far as clutch fluid level, you mean the slave cylinder? I already have topped it off but will check inspection port next time I go to my granpas (where the tools are lol)
As far as the shaking it mainly feels like its coming from the back of the truck.
there is also roughly im guessing 200,000 miles on it

There is to things I forgot to mention though i dont now if they matter sometimes when the engine is cold ill be goin down the road and suddenly loose all oil pressure, I put it ito neutral and restart it and pressure comes right back.

and also almost always after Ive driven somewhere and everything is warm I can be goin through a parking lot or driveway with clutch out in 1st gear idiling and hear almost kinda like a rachiting sound Ill try to record and post if ya'll want? kinda hard to describe

Thanks! Josh

 

To help diagnose trans problems, put your transfer case in neutral (Make sure it's in neutral, and block your wheels too) and run it through the gears. You will be able to hear/feel if the synchros are gone. If there are no more vibrations, it's rear driveline components (driveshafts, axle, etc.). If you still have vibrations, depress the clutch. Assuming the clutch is off the flywheel (that is, working), if you still have vibrations it's an engine problem. Being that it starts at a certain rpm, not roadspeed I'm thinking more in the direction of engine/input shaft.

Having it start at that rpm in those gears with a zf means its happening almost all the time; that is, any time above ~10 mph. And if it feels like a jerk> u-joints.

Your vehicle is equipped with a hydraulic clutch, so it's not exclusive to the slave cylinder. The reservoir is on the firewall next to the brake booster, so if thats what you checked, you're good.

You mentioned your spedo is gone, dose your Odo still tick/ was it working when you got it? if not, it may have a few more miles on it then you think.

The inspection port is just a rubber flap on the bottom of the bellhousing, no tools required save a pair of pliers if you need grip.

Does if have to be in neutral to get the oil pressure back? Check the connection for the sensor. And did you change the oil when you got it? Its always a good idea, and next time you do, let it completely drain then add the amount in the manual and scribe a new fill line an the dipstick.

Clutch out, you mean not depressed, right? Does if sound like gears chattering?(not completely engaged) Ask someone old enough to remember what a syncro is to give a listen.

To recap>
transfer case in neutral, clutch up, no vibration-----> Transfer case, u-joints, unbalanced driveshaft, unbalanced wheel, something in the diff housing.

transfer case in neutral, clutch up, with vibration-----> tranny or engine

Clutch off flywheel(depressed and working), no vibration-----> tranny

Clutch off flywheel(depressed and working), with vibration----->engine
-Mike

 

Speedo- it wasnt even hooked up when we got it it got hooked up and worked for a lil while but eventually got so off the you can be goin 75 and it read 15 to 20 and it bounces alot to. I was goin to hook a drill to the end of the speedo cable to see if it was broke and also check the gears.

Transfer case test- Ill do that tomorrow when I get home from school and take notes and put on here. (forgot to do it on my break to day)

The vibration- I was on my way home from work today and I could feel it pretty good (sometimes its worse sometimes its not) but I noticed that when I press my clutch in it will go away that to me would seem like it would deal with engine tranny or the t-case, Cause even if I press the clutch in the driveshaft, diff and tires would still be goin the same speed. Feel free to correct....im 17 ad still trin to learn

Sound- yeah it does sound kinda like gears chattering in my opion it sounds like gears chattering but with a lil bit of guess scratching sound mixed in.

and on the clutch out the I mean by the clutch isnt depressed sorry for any confusion

Oil presure- no it doesnt have to be in neutral for it to come back, I put it in neutral cause I was in heavy traffic and didnt want the engine running with no oil pressure so I put it in neutral to shut it off and restart it, It does have to be restart though for it to come back. It has also been changed several times most of the time by a mechanic.

Thanks again! Josh

 

BTDT and mine turned out to be a badly worn "driven" gear.
they are cheap and easy to replace, might check that? :)

It'll look like new if it's good. The worn one I had was the first
and only worn speedometer gear I've ever seen, all the rest,
no matter how old looked like new. And that includes old VW's
that'd been turned into dune buggies and all.

It came inside the '90 F250 parts truck with a ZF 188k miles.

I still have the originals in my '75 F150 T18. LOL :)

Alvin in AZ
ps- DuPont's Multi-Use works great for speedometer cables
and motorcycle throttle and clutch cables.

 

That's what im thinkin mine is to. I just have to check it lol


And to answer your questions
Transfer case neutral go through gears like normal driven----slight vibration mainly felt through the gear stick, im guesing mainly cause engine was running

Transfer cause neutral with clutch pressed down----same slight vibration as before im guessin cause the engine was runing

Thanks for any comments!! Josh

 

That slight vibration should/might be normal. The real question is is that the same vibration you feel going down the road? If no ( I assume it isn't) then its driveline. That jerk makes me think u-joint, check them again. If you're sure it's not them, driveshaft balance weight missing, wheel weights missing, and pull the diff cover, see whats going on in there. I'm really thinking u-joints.
-Mike

 

The drive shaft was replaced with a junkyard one about a year ago and has been practically a daily driver since to will defiantly check the drive-shaft weights and tire weights. And been wantin to change the oil in both diffs so I guess this gives me a good reason to!

Thanks! Josh

 

Wow, you lucked out with a junk yard drive shaft! :)

Those things are really touchy suckers, don't take much to mess
one up either (if you are sensitive to vibrations in your vehicles).

The way I check for stuff like that is to get the vehicle up off the
ground and then start it up and run it at different speeds on the
speedometer.

Try not to run over yourself. ...it'd prob'ly hurt. ;)

I've done a quite a bit of that crazy sounding business and never
had a problem. YMMV! LOL :)

---------------------------

Anybody else on here -true- their own tires?

Alvin in AZ

 

When you put is the Driveshaft, did you use jy u-joints too? A missing wheel weight or driveshaft weight would cause vibration, but not a jerk. Jerks are u-joints or lockers.
-Mike

 

x2

And a loud clunk if it's a loose 8.8" (which it ain't).

Butthead in AZ

 

Ok here is the story to clear up the driveshaft.

I got mad cause I didnt think the 4 wheel drive was working so one rainy day I got out in the yard in the water in 4wheel low range and dumped the clutch and floored the gas. Needless to say I spun the tires but I also spun the splines off the rear driveshaft. Smoothed that sucker out........ So we took it to a mechanic thinkin it was the tranny (input shaft) and he drove it in the shop in 4 wheel drive (go figure) even locking in the hubs I couldnt get it to go anywhere in 4 wheel. SO he went through about 40 different junkyard driveshafts and finally found one that fit and we took her home

SO Its possible its outta balence or wait fell off, Im 17 and probably rougher on it than I should be (what teen aint) but I also do my best to take care of it to
On the tires they are VERY worn down and are crap, one wheel I know is out of balence cause awhile back walmarts machine broke and they couldnt balence it. Its front passenger I think if that matters.

Hope it clears anything up!

Thanks! Josh

P.S. I have no clue if he used new or old u-joints. And what do you mean by lockers. I know the rear diff has a limited slip? And front is open? I think