Weird shudder on decel…

Specs:
2017 TRD Spirt manual transmission
3” lift
285/75/17 (34-ish”) tires

since the day we lifted this two and a half years ago there’s a weird shudder. Only happens when slowing down. The entire truck shakes and it’s been getting worse. Happens from ~18–> 10 mph and is not noticeable anywhere else. Now, this happened with the old 33” tires and new almost 35” tires.

Braking has no effect on it. Also whether or not I’m in gear effects it. I can be in 2nd gear and it does it. I can be in neutral and it does it. I can be on or off the brakes and it does it.

I’m at a loss. I’m going to put it on a lift at work and have a tech peek at it but is this something you all have experienced before? Could it be the needle bearing in the front diff hammered and I need that bushing? Or is it maybe something else. I know all suspension components are tight with no play. Thanks.

 

I’m think some use a wedge like shim in the rear spring perch to change diff angle.

Definitely list very specific specs on lift and pics, if you want any real help from the experienced.

 

Does it go away in 4wd? What do you have for lift on the back of truck? Any axle shims, carrier bearing drop?

 

it seems to change oscillations if that makes sense in 4HI versus 2WD… it’s still there but not as bad. I may try the ecgs bushing when I do the axles later this month

 

Dobinson’s 3” lift with heavy load front and rear springs. Nothing crazy. Did the carrier bearing drop, did not yet do a diff drop.

 

I would due ecgs and a 2 to 3 degree shim in rear. These trucks don't like anything over 2" - 2.5".