Truck pulls sideways under acceleration or deceleration...

[tractor_boy]

Hey guys I have a 93 supercab ranger, 4X4 4.0 manual. I'm pretty rough on the thing, just like any young stupid guy, but I keep up on all the maintenance, as I'm a mechanic too. Well maybe now I've done it though. I was hauling this big ol steel hydraulic press in the bed of my truck (~1500#) and jumped a curb with the rear tire when going around the corner. OOPS.
So I just noticed this problem, don't think it existed before the curb incident, but when I floor it, my truck drifts to the left (about 10 feet in 300-400 feet maybe), when I let off the pedal and decelerate in gear, it drifts right about as much, and when I coast out of gear, it tracks perfectly straight. Braking, if there is any side pull it isn't noticeable. Looked underneath and everything still appears tight, nothing obviously wrong.
But the left side does sit maybe an inch or so lower in the rear.
I'm guessing I sprung my spring...? If I did, no big deal I have a 4 inch lift with new 4 or (5?) leaf springs in the shop that's going on the truck in a month soon as school is out.
And if I did frame damage, no biggy there either, I'm beefing up the frame at the same time as the lift too... beefing it up to handle a "little bit" of torque from a hopped-up baby Cummins (3.9L 4BT). That will make for a sweet little truck with some power, noise, smoke, a lift, and better MPG all the while.
Let me know what your ideas are on the drifting please... And yes I already know I shouldn't be hauling that kinda stuff any more.
thanks in advance,
Chris

 

[Ozwynn]

don't know if its normal but it sounds a little like torque steer.

 

[AngryLepercon]

I would say maybe you bent the wheel a little or you broke a bolt off something in the rear.

 

[tractor_boy]

Looking in the mirrors while driving there is 0 wobble so that kinda rules out bent wheels.
And as far as the torque steer... hmm my best guess was one of the rear springs was so weakened that it would flex more than the other, causing the axle to shift a bit? The truck bed does seem to twist up a bit more than I had noticed in the past while under hard acceleration. Driving it, feels definitely like the problem is in the rear end though. A little bit flimsy and loose almost like weak shocks, but those are new.

 

[doorgunner]

jack up the frame at the rear to get the tires off the ground with the suspension hanging & see what hangs weird-looking...jack-ass kick both the tires a couple times to see if any bolts are sheared

 

[79machowagon]

could be a broken center bolt or loose u bolts

 

[kcm1582]

Torque steer is usually associated with fwd cars. Sounds like a suspension issue. Id look at the spring hangers and ubolts. Or you could have broken the spring itself.

 

[Ozwynn]

Torque steer is usually associated with fwd cars. Sounds like a suspension issue. Id look at the spring hangers and ubolts. Or you could have broken the spring itself.

well duh, I just said it sounds like it. check everything from the motor mounts to the rear bumper. check every bolt and every screw and every weld. then let us know what was causing it.

 

[94STXRanger]

did you check your tire pressure?

 

[martin]

sounds like the rear axle is moving slightly. check the front bushings on the leaf springs and also the mount, it may have rusted and be moving slightly.

 

[Legend]

I had a steel belt break in a radial tire that behaved exactly like that. The only way I finally found it was to rotate the tires and the directions changed. Then I had to swap out each tire until I found the one with the broken belt. Once the tire was off the rim, there was no indication of any problem, but the dealer was with me when we were swapping and testing and could verify that the tire was the cause.

 

[tractor_boy]

I have fairly new Cooper Discoverer STT's on there. If that's what it is, (broken steel belt) well I'm gonna pat myself on the back for buying tire insurance when I got the tires. Can't even get it into my shop for a week or two but I'll rotate the tires soon as I can and see if that changes anything. Thanks for the ideas guys I'll be sure to let you all know what it was...
Chris

 

[naford]

Broken shocks will cause this but if you hit a curb hard enough or at the right angle it could be a bad tire.

 

[doorgunner]

Be sure to let us know what fixed the problem

 

[tractor_boy]

Well I fixed the problem guys!! Took me awhile to get around to posting it up but the problem is solved. The left rear spring was bent and weakened. When I would accelerate or decelerate it would flex more than the right spring, allowing the axle to shift, hence the "torque steer". Solved the problem by installing new tough country springs when I lifted the truck. I did a 4" suspension lift, 2" body lift, and replaced every single bushing on the truck at the same time. It handles so much better now. Here are some pictures:
Before:

After:

During:

Bent left rear leaf spring can be seen on the right. It's noticeably easier to compress than the right spring and sits lower when uncompressed. Clearly the culprit of the torque steer symptoms!

Compare the new and old springs. Feels like I'm driving a F350 with the new springs. They have twice as many leaves.

Thanks for your suggestions all!
Chris