Help!!! Drive Train movement during Acceleration

[jbh]

Hi all. I need a bit of help trouble shooting my problem...

Oh, and great site... I have used the loads of info here for quite a while... although new to posting.

so here it goes...

1999 Ford Ranger XLT SuperCab 4X4 5 speed manual

When I accellerate from a dead stop in first, the torque from the motor causes simething in my drive train to move. It feels like the motor is shifting back... It also happens after decellerating in gear, then accelerating again... Like having the reverse torque from decceleration moves it in the other direction.

I have already replaced my motor mounts... and no change to my problem... a smoother idle... but still shifting somewhere in my drivetrain...

I don't know what to look at next... rear suspension? Drive shaft? Differential? I don't know...

Please lend me a hand at trouble shooting this problem...

it happens in 4-wheel as well...

Thanks.

-jbh

 

[jonafer]

have you check'd the tran's mount?

 

[jbh]

have you check'd the tran's mount?

Yes, I replaced the trans mount as well... and no change...

 

[jonafer]

driveshaft bolt's?

 

[jbh]

driveshaft bolt's?

Maybe, I was thinking U-joint... no real visible damage... no play... could it be rear suspension? maybe loos U-bolts... or play in the leaf spring assembly?

-jbh

 

[gijoecam]

I still don't understand the problem you're describing... can you give some more specifics, or maybe try describing it differently?

(I realize this may sound dumb, but try describing it like a woman would... "It goes clunk, click, bang, whirr instead of clunk, click, bang, wheeze)

I'm just not clear on the description...

-Joe

 

[jbh]

During acceleration, light and heavy... it there is a shifting of the drive train. You can hear a slight clunk with the movement. It feels like part of the driveline is going clunk under applied torque from the motor.

when deccelerating in gear, the clunk is much less apparent but in the opposite direction.

when accelerating again, in 1st, 2nd... from a moving start, the same clunk.

This occurs from a stand still, moving acelleration (low speeds up to 40 mph), moving hard acelleration (low and higher speeds - up to 70 mph)

there is no vibration.

no constant noise

the feeling of the movement is more apparent than the noise itself. I can feel it move through the shifter, steering wheel, floor pans, etc...

I hope that helps... I really appreciate your help with this.

I know that a slight movement is normal with a manual transmission... IE. feeling the torque/power pass through the transmission (when holding the shifter), but this is a bit stronger of a clunk/movement...

 

[gijoecam]

Aaah, OK... to me, it sounds like the pretty typical driveshaft slip yoke spline hanging up. The spline tends to stick, so all you would need to do is drop the driveshaft, slip the spline apart, liberally coat it with grease, and slip it back together. It might fix it for a while....

That's my best guess...

-Joe

 

[jbh]

great... I'll give that a shot when i get home today...

Everyone here is super helpful...

thanks again... I'll post the results tonight.

-jbh

 

[rwenzing]

I agree that you're experiencing "slip/bump" in your truck's drivetrain - very common and very annoying, IMO.

Greasing a 2WD Ranger is fairly easy because the slip yoke just slides over the output shaft and into the tailshaft housing of the transmission. Your 4x4 will be a bit more involved because the spline is within the body of the driveshaft itself and it's covered by an accordion boot with crimped on clamps.

Ford sells a special PTFE grease for this problem for $25/pound!

Worst thing of all is that the grease fix is not permanent. I've owned 3 Rangers and found that greasing the spline is good for only about 3~12 months, even if you spring for the magic grease. I got tired of that and installed traction bars that eliminate the problem at its source. Controlled axle windup = no slip/bump.

 

[jbh]

who makes a good traction bar kit that would fit my 1999 ranger xlt? That sounds like a good solution... along with some greasing...

-jbh

 

[rwenzing]

James Duff made them for years, then discontinued them, then moved to Tennessee, then made another production run. I don't know the current status.

http://www.jamesduff.com/