I got 1994.5 f250 with a vibration / shuddering going on when I'm driving down the road and it's driving me crazy! At about 3mph you feel like your going over one of the stop sign bumps , and it stops all virbrations or shuddering until I get in between 30-35 mph then defiantly you can feel it throughout the cab and steering wheel . After 35 mph exactly all virbrations go away and it's a smooth driving truck until right at 50 mph the virbrations comes back and is almost just as present as the one that occurres at 35mph . From 50-55 mph the virbrations in the cab and steering wheel (like I'm riding over a rough piece of road) and anything over that it might've smooth on some high speeds but around 60mph the truck has a slight shake and I really don't drive the truck over 65mph due to the 4:10 rear end and anything Over 2k rpms is out of its powerband . But tranny is new , u-joints have no slack in them what's so ever , t-case bolts are firm , it has new tires and have been balenced , rear end severcing everything checked out and I'm beating my head on the wall with this if anyone would please chim in it would be greatly appreciated !

 

Did the vibration start after the new tires or before? It doesn't sound like driveline to me.

 

I have had this truck since I was 16 and I have 5 years worth of drive line work done to this trying to work all the bugs out of it , and it's always done this since I've owned it , I do know that front leaf springs are sagging , front shocks have been replaced and I always keep the t-case and lock out hubs unlocked at all times . But I've been beating my head on the wall since I've had this truck trying to get rid of the shuddering driveline virbrations and it's only at those specific speeds and I do have the bw 1356 t case if that helps

 

What driveline work have you done?

 

I changed the rear end fluid with 75-140w with the friction modifier( gears and yoke , etc looked solid ) , all u joints (3 joint ) have been replaced with moog parts and were greased , transmission was replaced by a very reputable shop ( trans shift on schedule for the most part sometimes it will shift early into over drive ) new 285/75r16 tires and balanced, new shocks , motor mounts seem be in good shape the motor doesn't vibrate at all , and the rear brakes have been completely over hauled just about but that's all I can think of that I've done to it

 

If that work has been done in an attempt to solve the issue, and it has remained the same, then I would look at the front end/steering components (ball joints, tie rod ends etc.).

 

Did this just start, or did it start after having something fixed?

 

It has been an in going issue since I've had the truck , the front inner and out bearings have been replaced with new mile marker lock out hubs , inner and outter ltie rods were replaced with moog parts and the steering wheel had been adjusted , there has always been a slight knock on the front passenger side when ever the suspension joust or rebounds but I'm not able to tell if ball joint are nessessarly the issue with the shuddering vibrations

 

What about tires/rims? Shouldn't be that drastic at 3 mph, but just a thought.

 

You could put the rear up in the air (on jack stands and solid ground!) and run it up to 50 mph and see if the symptom persists. I agree with the above idea about possible bent rim. While the wheels are turning, check for how true they run.

 

Check and see if your drive line yokes are in phase. The drive shaft could have been removed at one time and put back wrong.

 

Sorry For the late reply guys , I found out that the tire shop that I've trusted all these years and have had speed specific shuddering/vibrations had only 30 psi in all tires . I filled them up according to the door sticker 55psi front and 80psi in rear and drives completely fine now but there is one thing I found also . I belivebthis truck had the absolute ***** beat out of the front end and some one tried to fix it

 

I really appreciate everones help ! the virbrations are still present but no where as much as before pumping the tires , I'm going to look at the yoke phasing tomorrow and let y'all know what's up with that as well , and what do y'all think of the front end ? Other than it being a d50 lol

 

One thing for sure, the pivot bushings are worn completely out.

 

Do you have a two piece rear drive shaft? I get a shudder when pulling away from a stop when the support bushing is not spaced up or down correctly.