Correct front pinion angle after lift / stock ds

[samw5]

Just finished installing my MC True Dual 2.5 lift this weekend.

I still have to recenter the axle (shifted about 1.5" passenger). I'm guessing I would just need to unbolt it pass side, shorten the trackbar and lift the axle on that side till it fits? (any tip to make it easier?).

Didn't do a whole lot with the upper control arms but line up the holes so they fit. Right now looks like I may have a bit of negative caster (C appears tilted forward). Still driving just fine even at speed. My bigger concern is the front driveshaft angle. What should I be looking for?
I have a stock driveshaft for now. Not planning on going crazy wheeling till I can get an aftermarket unit but in case I have to hit a trail and flex, what should I set the angle to in order to not damage anything else besides the driveshaft itself?

Also forgot to add that I'm on 35" right now but bumping up to 37" this weekend.

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[whysoserious]

I still have to recenter the axle (shifted about 1.5" passenger). I'm guessing I would just need to unbolt it pass side, shorten the trackbar and lift the axle on that side till it fits? (any tip to make it easier?).

I typically use a ratchet strap, one end on the axle and other end on opposite frame (depending on which way is needed). This way, after unbolting the track bar, you can shift the body over the axle and get it just right.

Didn't do a whole lot with the upper control arms but line up the holes so they fit.

Did you set the UCA's to the recommended length per Metal Cloak? If so, you should be close enough for an alignment.

My bigger concern is the front driveshaft angle. What should I be looking for?

This is where you should be looking...

 

[samw5]

The MC instructions didn't have the specs for the 2.5" springs... only the 3.5.
And no I didn't adjust them to anything outside of making the arms fit in the axle holes.

 

[whysoserious]

The MC instructions didn't have the specs for the 2.5" springs... only the 3.5.
And no I didn't adjust them to anything outside of making the arms fit in the axle holes.

Page 8...

Slide 1 (metalcloak.com)

 

[samw5]

Ya... Metalcloak 3.5" lift.... I have the 2.5"

I suppose I can try to go back the 6 degrees listed. that might work.

 

[whysoserious]

Yeah, that 19.75" is the same for the True Rate and the Game Changer, regardless of the lift height. It should get you within the ballpark of MC caster spec of 6 degrees. Post alignment data will let you know how close.

 

[Zachanadandy]

Trying to dial in pinion angle on the front axle is simply measuring the less important spec. Set the caster at 6⁰ and the pinion angle is set... and the jeep tracks better.

 

[samw5]

i was under the impression that pinion angle was more important than caster all things considered...

 

[JTPatriot]

6 -6.5 degrees of caster will get you a good driving (tracking) setup. Any more caster will give a bad angle at the pinon and driveshaft and will induce vibration when in 4 wheel drive.

 

[kevman65]

i was under the impression that pinion angle was more important than caster all things considered...

On the rear, pinion angle is more important.

On the front, caster is more important for driveability. But, you also need to make sure your front shaft is long enough AND that there isn't any binding.

 

[Wheelin98TJ]

i was under the impression that pinion angle was more important than caster all things considered...

Factory service manuals say pinion angle has priority over caster angle.

What they mean is don't run a caster angle that causes vibrations. The pinion angle might not be perfect, but if you don't feel vibes, you should be good.

 

[Sbro2021]

Unless you are going to cut the axle housing apart and re-weld it to rotate the pumpkin up, there is nothing you can do to change pinion angle and still have correct steering geometry, simple as that. All of the geometry/angles were set on the axle for stock conditions. Only other solution to fix pinion angle is buy an aftermarket housing that was setup for pinion angle with the amount of lift being used. If ya want to go ghetto to try and make the t case side boot live, I massaged that flange on mine with a custom wood block and BFH to get it not to bind. I’m running 4.5 inches up front on the stock shaft with 10” of down travel and I still have an intact shaft/boot at 80k.

 

[Gizmo]

Out of curiosity. Isn’t a JL axle housing the same as a JT as far as caster related to pinion angle. I only ask because on the JL forum it seems to be a given that 0 degrees pinion angle means you have about 6 degrees caster. Sure answers the OPs question easily.

 

[rharr]

Unless you are going to cut the axle housing apart and re-weld it to rotate the pumpkin up, there is nothing you can do to change pinion angle and still have correct steering geometry, simple as that. All of the geometry/angles were set on the axle for stock conditions. Only other solution to fix pinion angle is buy an aftermarket housing that was setup for pinion angle with the amount of lift being used. If ya want to go ghetto to try and make the t case side boot live, I massaged that flange on mine with a custom wood block and BFH to get it not to bind. I’m running 4.5 inches up front on the stock shaft with 10” of down travel and I still have an intact shaft/boot at 80k.

Like he said, there isn't much you can do for front pinion, if you rotate the pinon up it screws with the pre-set steering angles at the knuckles.

best setup is to go with a aftermarket front drive shaft that has a double Carden joint and a splined shaft that allows things to extent and contract.

i am running the stock shaft and it has self adjusted the aluminum flange as needed as i flex it out. I figure once i break the shaft or damage the sealing gasket i'll get a traditional drive shaft.

 

[samw5]

i am running the stock shaft and it has self adjusted the aluminum flange as needed as i flex it out. I figure once i break the shaft or damage the sealing gasket i'll get a traditional drive shaft.

ya that's where I'm at... haven't had issues offroad yet, albeit I'm not doing tons that require full flex. i figured that once adam runs a sale I'll probably grab one.

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