Rear Blocks removed on an FX4 XLT ft. Space White

[TexasTruck]

Interesting that you didn't have any drive line vibrations after removing the rear blocks. Lowering the rear would slightly increase the output flange angle on a short bed. I guess it's not enough to matter.

When I leveled my truck 2.0" I picked up drive line vibrations around 50 to 60 MPH. I checked the pinion and output flange faces and I was 2* out of phase. I ended up installing a 2* SBC shim, problem solved. I'm not a fan of shims, more of a quick cheap test. I need to find a tapered block that's equivalent to the factory height now.

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[WhiteLightningnshitshadow]

Interesting that you didn't have any drive line vibrations after removing the rear blocks. Lowering the rear would slightly increase the output flange angle on a short bed. I guess it's not enough to matter.

When I leveled my truck 2.0" I picked up drive line vibrations around 50 to 60 MPH. I checked the pinion and output flange faces and I was 2* out of phase. I ended up installing a 2* SBC shim, problem solved. I'm not a fan of shims, more of a quick cheap test. I need to find a tapered block that's equivalent to the factory height now.

It didn't change the pinion angle at all because the blocks were flat. The angles the output and input sides were reduced, but should be identical in delta to stock delta.

 

[nezff]

Interesting that you didn't have any drive line vibrations after removing the rear blocks. Lowering the rear would slightly increase the output flange angle on a short bed. I guess it's not enough to matter.

When I leveled my truck 2.0" I picked up drive line vibrations around 50 to 60 MPH. I checked the pinion and output flange faces and I was 2* out of phase. I ended up installing a 2* SBC shim, problem solved. I'm not a fan of shims, more of a quick cheap test. I need to find a tapered block that's equivalent to the factory height now.

It didn't change the pinion angle at all because the blocks were flat. The angles the output and input sides were reduced, but should be identical in delta to stock delta.

My 4wd looks like it has shims. Not sure.

 

[TexasTruck]

Gosh, my truck has flat blocks too. I measured the pinion flange before the leveling kit and it was 2* opposite the output flange. Because of the rake the factory adds negative pinion angle to account for pinion rise during hard acceleration, towing or load squat.

After leveling my truck, the pinion was 0* to the 2* output flange. So that means any pinion rise will create more vibration and explains when I let off the gas at speed, the vibration disappeared (pinion dropped).

Any way, glad it worked out! Your truck looks great with just a little rake!

 

[Buyer2021]

My 4wd looks like it has shims. Not sure.

FWIW the workshop manual makes no reference to 'shims' separate from the 'blocks' in the procedures relating to spring / axle removal & replacement.

There is reference to three different versions of the OE 'blocks', and though not mentioned in the WSM some of those may have a taper cast into them (the WSM does warn about maintaining proper front/rear orientation when reinstalling the OE blocks).

Separate shims are mentioned in the WSM procedure for adjusting pinion angle, but that seems to be for mitigation of a problem, not as OE parts from the factory.

 

[WhiteLightningnshitshadow]

Yeah the shims arent really any different from low blocks. It's not like they're unsafe or anything. I have shims on my other truck.

 

[snapper9601]

anybody know the torque spec on the U-bolt nuts?
@Buyer2021, maybe it's in the WSM?

 

[Buyer2021]

anybody know the torque spec on the U-bolt nuts?

Posted here: Axle U-Bolt Tightening Torque Specifications?

 

[TexasTruck]

This is the best place for information. I learn something new every day. The participation is the best I've encountered - thanks y'all!

 

[DcnPat]

lol Alright so the fuel door is plastidipped black. I like it, wife hates it, everyone else seems to hate it too lol. I think it gives the truck some dimension personally.

Seems appropriate - the fuel tank is the black hole where money continously disappears

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