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Crank slides forward/backward 1/8" or so?

BALTANAKT

NAXJA Forum User
Location
Berthoud, CO
Hi All,

I've been trying to narrow down what's been causing my chirp.

(For that thread see here: http://www.naxja.org/forum/showthread.php?t=1139967)

I noticed when replacing the harmonic balancer that the crank together with the HB will slide forward and backward 1/8"–3/16". Furthermore, when I push it rearwards with my hand, and then start it, it automatically slides to the forward position and stays there while running.

Curious if this is normal?
 
Nope, that's scary! Obviously your thrust bearing is shot!
 
Got under the Jeep and I could see when the crank shifted forward, that's when the belt started chirping! So it's definitely got to be fixed.

Now I am wondering whether I should have new bearings installed, or just swap in a crate/rebuilt motor.

This one seems to be a relatively good deal, but install is going to make it very costly: http://www.hiperformer.com/engines/jeep-cherokee-rebuilt_engines-amc_242lb_1.html

Sadly, I don't have a garage.
 
Nope, that's scary! Obviously your thrust bearing is shot!

My 400,000 mile 78 Dodge V-8 had 1/4" of play there before it barked LOL. But I had fried the torque converter shaft seals every 12 months for 3 years before....It died, It was still running but it made one hell of a racked the day it got too worn.... and barked at me. Replaced everything but the crank case.
 
The #4 bearing (thrust bearing)!
 
So I'm curious what causes crank walk in the first place on these 4.0's?
Sitting at a stop with the clutch pushed in.

A bud bought an early 90's truck with less than 90K on the odometer. The truck had one owner since new; a "mature" man who pretty much just drove it around town. That V-8 had 1/4-inch of crankshaft end play.
 
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