Pinion Angle Correction

[85_Ranger4x4]

I have a rather harsh vibration under hard acceleration and a very faint one (that could very well be tires) on highway cruise.

So I checked things with my angle finder, I am 5* off between the t-case output and pinion. Shims come in even numbers, 4* or 6*, better to be a little over or a little under?

And does the center bolt in the spring pack need to be replaced with something that has a longer head?

 

[Curious Hound]

I THINK I have read that it is better to set it a degree is so too high. But wait til someone more authoritative comments on that.

I would think having a longer bolt head for the center of the spring pack would be good to help locate the shim. The lowering kit I put on my F150 came with shims and new bolts for the spring pack. I didn't measure the length of the head, though. It's probably a good idea.

 

[don4331]

The nose of the pinion is going to rotate up, amount dependant on much force is being applied to the skinny pedal while going forwards. (Opposite for reverse.)

So. depending which way you are off, you want it so when the rear axle rotates a degree from compression of spring bushings, flexing of leaves, etc, that the end result is where you want it.

 

[bobbywalter]

Low.


Try the both.

Make sure you are in plane.

 

[85_Ranger4x4]

The nose of the pinion is going to rotate up, amount dependant on much force is being applied to the skinny pedal while going forwards. (Opposite for reverse.)

So. depending which way you are off, you want it so when the rear axle rotates a degree from compression of spring bushings, flexing of leaves, etc, that the end result is where you want it.

Yup, I stuck my gopro on it a couple nights ago to see if that correlated with the vibration, it sure seemed to. You an see the camera start to shake at the top end before I shift while I am in second and third gear.

As far as driveshaft or whatever, it used to be smooth as glass cruising before I did the belltechs. I have had the vibe on hard accel since the trans swap last year... without rebuilding the crossmember and redoing my exhaust there no easy fix for that though. Sitting in my driveway the trans is tipped down 3*, axle up 8*.

 

[Shran]

I'd be tempted to go with the 4* shim as per what don said. Whatever you end up doing, don't use aluminum shims. I have had them come apart.

 

[85_Ranger4x4]

I'd be tempted to go with the 4* shim as per what don said. Whatever you end up doing, don't use aluminum shims. I have had them come apart.

I have heard cast aluminum are junk, stay with forged aluminum or steel. I have my eye on steel ones.

 

[Curious Hound]

Figures I had it backwards. Good thing you didn't take my advice on this one

 

[Snoranger]

I’d go with 6 degree...
6 will put your rear at 2 degrees. Under a load the pinion will climb up 1-2 degrees (or more if your springs are weak or worn) and put it at 3 or 4 degrees while driving.
You don’t need to be exact... just within a degree or two will be fine. Right now you’re probably at 9-10 degrees while driving... that’s too far off from the 3 at the trans.

 

[franklin2]

Yup, I stuck my gopro on it a couple nights ago to see if that correlated with the vibration, it sure seemed to. You an see the camera start to shake at the top end before I shift while I am in second and third gear.

As far as driveshaft or whatever, it used to be smooth as glass cruising before I did the belltechs. I have had the vibe on hard accel since the trans swap last year... without rebuilding the crossmember and redoing my exhaust there no easy fix for that though. Sitting in my driveway the trans is tipped down 3*, axle up 8*.

How did the rearend end up so high? That sounds like a Bronco II setup. It's what you would run if you have the double cardan joint at the transfer case end.

 

[Bgunner]

Only because it is a pet peeve of mine, To use the degree symbol on a PC Press and hold ALT and enter " 0176 " (without quotes) and you get the degree emblem as such ( ° ) 8° - 3° ect. the * is for multiplication and such.

I didn't notice the shake but I have to agree with the 6° shims to help the drive shaft straiten out under acceleration. That axle is twisting quite a bit under all that V8 power thrown at it.

 

[Snoranger]

Only because it is a pet peeve of mine, To use the degree symbol on a PC Press and hold ALT and enter " 0176 " (without quotes) and you get the degree emblem as such ( ° ) 8° - 3° ect. the * is for multiplication and such.

I didn't notice the shake but I have to agree with the 6° shims to help the drive shaft straiten out under acceleration. That axle is twisting quite a bit under all that V8 power thrown at it.

I knew about the alt code... I just looked up how to do it on my phone.
°°°°

FYI... if you have a iPhone, hold down 0 and it will give the option of a degree symbol.

 

[Uncle Gump]

I usually do it this way.... degrees

 

[Snoranger]

I usually do it this way.... degrees

Look at Mr. Fancyplates... “I spell out the entire word.”

 

[Uncle Gump]

I would rather not clog up what little memory I have left... I wasted to much of it in my youth.