Rear pinion angle?

[Mxjunky9]

Can anyone tell me what the stock rear pinion angle is on a Sport S Max Tow? I’m getting a vibration at around 25 mph and 45 mph that I’m trying to figure out. Currently at 4° pinion angle but thinking I need to dial it in close to stock. 3.5” Metalcloak lift with 37” cooper sst and beadlocks

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[ShadowsPapa]

You should be concerned about the angle difference front of shaft to rear, not just the pinion angle.
You have moved the pinion down as well as possibly changing the angle of the pinion so you have dropped the shaft rear, increasing the front angle.

 

[Mxjunky9]

You should be concerned about the angle difference front of shaft to rear, not just the pinion angle.
You have moved the pinion down as well as possibly changing the angle of the pinion so you have dropped the shaft rear, increasing the front angle.

right I get that. I talked to Will at Metalcloak and he said he hasn’t heard of anyone having to change the angle at the carrier bearing by adding a spacer at that joint. Only way to adjust that angle is with a spacer right? He said they only try to get the rear pinion angle back to stock Which I didn’t measure before I

 

[Renegade]

right I get that. I talked to Will at Metalcloak and he said he hasn’t heard of anyone having to change the angle at the carrier bearing by adding a spacer at that joint. Only way to adjust that angle is with a spacer right? He said they only try to get the rear pinion angle back to stock Which I didn’t measure before I

With CV joints, it shouldn’t really matter as long as they are within the operational range. Spicer does have a drop kit for the driveshaft though.

 

[ShadowsPapa]

With CV joints, it shouldn’t really matter as long as they are within the operational range. Spicer does have a drop kit for the driveshaft though.

CV doesn't have the speed-up/slow-down "cycle" with each revolution like the others do making it critical to match angles, quite true. Forgot they were CV. Biggest thing is maintain some angle and not have too much angle.

Earlier Jeeps had some real issues as those short shafts (with Hooke type joints) don't play well with mis-matched angles.

 

[Mxjunky9]

CV doesn't have the speed-up/slow-down "cycle" with each revolution like the others do making it critical to match angles, quite true. Forgot they were CV. Biggest thing is maintain some angle and not have too much angle.

Earlier Jeeps had some real issues as those short shafts (with Hooke type joints) don't play well with mis-matched angles.

I honestly don’t think my vibration is coming from rear drive shaft. Angle at TC is 2.5°, angle at carrier bearing is 2.5° and rear angle is about 4 °. I stacked washers and made a spacer for carrier bearing to test that theory and there was no change. Thinking the harmonic vibration I’m hearing and feeling is tire/wheel related

 

[cgflyer]

Can anyone tell me what the stock rear pinion angle is on a Sport S Max Tow? I’m getting a vibration at around 25 mph and 45 mph that I’m trying to figure out. Currently at 4° pinion angle but thinking I need to dial it in close to stock. 3.5” Metalcloak lift with 37” cooper sst and beadlocks

Pretty sure MC recommends a new drive shaft for their 3.5" lift

 

[Renegade]

Pretty sure MC recommends a new drive shaft for their 3.5" lift

That’s because of the extended length of their shocks, not the ride height.

 

[Mxjunky9]

Pretty sure MC recommends a new drive shaft for their 3.5" lift

That’s the front drive shaft they recommend changing and that’s because the shaft will hit the cross member at full droop and tear the boot off. But front drive shaft don’t turn when not in 4L so that wouldn’t be my vibration. I’m talking about the rear shaft.

 

[ShadowsPapa]

That’s the front drive shaft they recommend changing and that’s because the shaft will hit the cross member at full droop and tear the boot off. But front drive shaft don’t turn when not in 4L so that wouldn’t be my vibration. I’m talking about the rear shaft.

I chased down a weird vibration in one of my cars - took about 4 years and finally found it. I totally redid my rear driveshaft, had a racing shop go through it - balanced and better, heavier u-joints in it, checked pinion angle up one side and down the other as I had replaced springs - leaf springs can impact the angle of the differential in the rear. Some said - well, the drive shaft up front could be doing it. Geesh, and these were Eagle and Jeep people? Nope - in 2 wheel drive I could wire that shaft to the chassis and it wouldn't matter - the front shaft is NOT turning. You could not tell where it was coming from. Everyone asked - front, or rear? Left or right? Whole car!
It shook so bad at 65-70 it was shaking the dash, visors, and I was afraid of some real damage from fatigue stresses.
I took the tires to a shop - they all said there was NO runout, they were round and my wheels were fine. I checked the wheels myself with a dial indicator - all in spec for runout.
I swapped things around and finally gave up and decided just to avoid certain speeds and stay off the highway as much as possible.
I took it to an axle shop and they checked the wheels and tires and said all were fine, and aligned it (but since my front springs were wrong, the car sat high so they couldn't get camber perfect - oh, well)
Finally I decided to take the car to the next level in the international shows. I found a shop - the ONLY shop in Iowa, that does CNC wheel refinishing. I had made new centers to replace the plastic center caps that were shot, and needed them machined to final shape and finish anyway.
I left the wheels and tires with that shop and left them with a 5th wheel "just in case". A week or so later - they called, all done. I went and talked to the guy that did the work. I saw what I thought was the extra wheel I left sitting next to the others and asked- oh, you didn't need that wheel, thanks for finishing it anyway. He said no, that was one of the wheels that was on the car originally. He had to use the spare!
OK, why?
He said the wheel was EGG SHAPED, like it had dropped HARD into a hole. He was able to get it back into shape (they can literally squeeze wheels back into round)
He said when it put it in the CNC machine and it started to turn he instantly saw the problem!
Result - NO MORE VIBRATION.
Now, why didn't 2 alignment shops, at least 2, maybe 3, tire shops, not find or see the issue?
I could have put the car up on stands, put it in 4 wheel drive mode and let all 4 wheels spin at some speed - but I was doing other things and paid THEM to do that.
I'm saying - that one wheel, no matter where it was on the car, set up vibrations through the whole chassis - you felt it in the floor as much as anything. Steering wheel was always rock-solid, stable. Never any side-to-side movement of the wheel, braked fine, etc.
WEIRD.
I do recall hitting a spot in town where they had a big narrow trench cut into the concrete and a steel plate over it, but the plate had shifted and I hit that spot hard BANG, but never thought of it making a wheel egg-shaped.

 

[Mxjunky9]

I chased down a weird vibration in one of my cars - took about 4 years and finally found it. I totally redid my rear driveshaft, had a racing shop go through it - balanced and better, heavier u-joints in it, checked pinion angle up one side and down the other as I had replaced springs - leaf springs can impact the angle of the differential in the rear. Some said - well, the drive shaft up front could be doing it. Geesh, and these were Eagle and Jeep people? Nope - in 2 wheel drive I could wire that shaft to the chassis and it wouldn't matter - the front shaft is NOT turning. You could not tell where it was coming from. Everyone asked - front, or rear? Left or right? Whole car!
It shook so bad at 65-70 it was shaking the dash, visors, and I was afraid of some real damage from fatigue stresses.
I took the tires to a shop - they all said there was NO runout, they were round and my wheels were fine. I checked the wheels myself with a dial indicator - all in spec for runout.
I swapped things around and finally gave up and decided just to avoid certain speeds and stay off the highway as much as possible.
I took it to an axle shop and they checked the wheels and tires and said all were fine, and aligned it (but since my front springs were wrong, the car sat high so they couldn't get camber perfect - oh, well)
Finally I decided to take the car to the next level in the international shows. I found a shop - the ONLY shop in Iowa, that does CNC wheel refinishing. I had made new centers to replace the plastic center caps that were shot, and needed them machined to final shape and finish anyway.
I left the wheels and tires with that shop and left them with a 5th wheel "just in case". A week or so later - they called, all done. I went and talked to the guy that did the work. I saw what I thought was the extra wheel I left sitting next to the others and asked- oh, you didn't need that wheel, thanks for finishing it anyway. He said no, that was one of the wheels that was on the car originally. He had to use the spare!
OK, why?
He said the wheel was EGG SHAPED, like it had dropped HARD into a hole. He was able to get it back into shape (they can literally squeeze wheels back into round)
He said when it put it in the CNC machine and it started to turn he instantly saw the problem!
Result - NO MORE VIBRATION.
Now, why didn't 2 alignment shops, at least 2, maybe 3, tire shops, not find or see the issue?
I could have put the car up on stands, put it in 4 wheel drive mode and let all 4 wheels spin at some speed - but I was doing other things and paid THEM to do that.
I'm saying - that one wheel, no matter where it was on the car, set up vibrations through the whole chassis - you felt it in the floor as much as anything. Steering wheel was always rock-solid, stable. Never any side-to-side movement of the wheel, braked fine, etc.
WEIRD.
I do recall hitting a spot in town where they had a big narrow trench cut into the concrete and a steel plate over it, but the plate had shifted and I hit that spot hard BANG, but never thought of it making a wheel egg-shaped.

thanks for the input. Mine I cannot feel in the steering wheel only in the floorboard and brake/gas pedals. At around 25mph I can hear a whoo whoo whoo(or however you spell it lol) sound. When I put stock tires on I don’t hear or feel it. That’s why I leaning more towards tires. But I also know bigger tires can magnify problems. The issue is I had rims and tires on the Jeep before the lift and didn’t feel the vibration. Possible that It was there but new Metalcloak springs are making it seem worse? Idk. But tires is where I’m going to next. I don’t think it’s driveline

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