<HR style="COLOR: #d1d1e1; BACKGROUND-COLOR: #d1d1e1" SIZE=1> <!-- / icon and title --><!-- message -->
Howdy,

I have a 1995 F-150 4X4 with the 4.9l 300 and 5 sp manual. it is lifted 6" and has 35" bfg at tires, and 4.56 gearing. i have noticed there is alot of shaking or shuddering when i take off in first gear, especially on an inclined. . the whole truck in shuddering. any info is appreciated. thanks and gig em

 

How long has the lift been on the truck? anything recent that might have changed the pinion angle to change?
U-joint condition alright?
Trans mount still together?

 

i have had the lift for about 2 years. its a short bed regular cab. i had the driveshaft worked on when the gears were installed. that was maybe last summer.

 

OK, so have you done any inspections yet?
Look for broken leafs, or even a loose yoke? Bad u-joints, or the trans mount that I mentioned?

 

Sometimes you have to tighten the loose nut behind the throttle pedal.


But seriously, what 75F350 said, if it just recently developed, check the trans mount and u-joints. Also, I guess this question should be asked, how long has it been shaking like that? Since the lift was installed, or just recently?

 

The u joints are good. there is no play in the driveshaft...

 

What is the condition of the splines in the slip yoke / joint?
It is possible that you have some dry splines, and when the axle tries to move under acceleration, it is finding resistance at the splies causing the acceleration vibration.

 

I would suspect the angle has changed with the drive shaft/pinion. If there is a carrier bearing installed along the drive shaft, a fix might be to lower the carrier bearing with a spacer. But the question is how long has this been going on and is it related to the lift.