NAXJA Forums -::- North American XJ Association  

Go Back   NAXJA Forums -::- North American XJ Association > NAXJA Unibody Jeep Technical Forums > Jeep Cherokee XJ (1984 - 2001) > OEM Tech Discussion
HOME Member FAQ Sponsor Info Rules Bylaws E-Mail

OEM Tech Discussion Forum for OEM (Original Equipment) or stock XJs and MJs.

Reply
 
Thread Tools Display Modes
  #1  
Old September 15th, 2017, 06:51
BALTANAKT BALTANAKT is offline
NAXJA Forum User
 
Join Date: Jul 2015
Location: Boulder, Colorado
Posts: 191
What causes "crank walk" to occur?

Hey guys,

A year ago I picked up a '91 Cherokee with a 4.0 and an automatic transmission.

It ran great for six months, but then I realized the crank was walking back and forth about 3/8"-1/4", sending the pulleys out of alignment and making a huge racket.

I've heard you can get crank walk by riding the clutch, but this is an automatic.

I'm pretty much at a loss for being able to explain what happened, and I am worried about it occurring again once I put in a new motor. Could the tranny/t-converter/flex-plate be responsible in some way? Or was it something else?

Thanks for your help
Reply With Quote
  #2  
Old September 15th, 2017, 06:59
RCP Phx RCP Phx is offline
NAXJA Forum User
 
Join Date: Mar 2003
Location: Phoenix,Az
Posts: 11,636
Re: What causes "crank walk" to occur?

The only way you can have excessive end play is if the thrust bearing is toast and that is caused by wear or possibly something not installed correctly!
Reply With Quote
  #3  
Old September 15th, 2017, 07:15
Anak's Avatar
Anak Anak is offline
Mostly Harmless
 
Join Date: Sep 2013
Location: SoCal
Posts: 2,662
Re: What causes "crank walk" to occur?

3/8"-1/4" sounds like more play than a worn thrust bearing. I think you would have to completely eliminate that bearing and then some in order to get that much play.

Have you checked the balancer itself? Could it be loose on the crank? Or perhaps the outer rim loose on the center?
__________________
Project "Scope Creep": 1996 4wd 4.0L, AX15
Reply With Quote
  #4  
Old September 15th, 2017, 07:24
BALTANAKT BALTANAKT is offline
NAXJA Forum User
 
Join Date: Jul 2015
Location: Boulder, Colorado
Posts: 191
Re: What causes "crank walk" to occur?

Quote:
Originally Posted by Anak View Post
3/8"-1/4" sounds like more play than a worn thrust bearing. I think you would have to completely eliminate that bearing and then some in order to get that much play.

Have you checked the balancer itself? Could it be loose on the crank? Or perhaps the outer rim loose on the center?
Actually I put in a new balancer thinking that was the problem. That's when I realized the whole crank is shifting back and forth.
Reply With Quote
  #5  
Old September 15th, 2017, 16:13
techno1154's Avatar
techno1154 techno1154 is offline
NAXJA Member
 
Join Date: Apr 2003
Location: In the islands
Posts: 2,276
Re: What causes "crank walk" to occur?

Crank shaft thrust bearing? Isn't that part of the rear most crank main bearing? If that is so then both front and rear lips (sides) are only about 1/8" thick, iirc. Assuming that is true, it mean both front and rear lips are gone to allow 1/4" of movement,....or is it possible to put a bearing in that do not have the lips on both sides?
__________________
Patrick

#594
1996 XJ; 4.0L; AW4; NP231; SYE; D30 and D44; ECTED; 4.10 gears; 30X9.5 -15 BFG/AT/KO; 3" lift; Rusty's LCA; JKS ADJ UCA; Kevins ADJ Track bar; Drawtite Front Receiver; Dual Electric Fans; Dual Battaries.
Reply With Quote
  #6  
Old September 15th, 2017, 16:16
Anak's Avatar
Anak Anak is offline
Mostly Harmless
 
Join Date: Sep 2013
Location: SoCal
Posts: 2,662
Re: What causes "crank walk" to occur?

Sounds like time to pull the pan and figure out what is going on.

I can't imagine any way around it.
__________________
Project "Scope Creep": 1996 4wd 4.0L, AX15
Reply With Quote
  #7  
Old September 15th, 2017, 17:04
trippled trippled is offline
NAXJA Member
 
Join Date: Apr 2006
Location: colorado springs, co
Posts: 1,969
Re: What causes "crank walk" to occur?

It should be the middle bearing that's the thrust bearing, and it is pretty thick. there is the possibility of a torque converter ballooning under pressure, and basically forcing the crank into the thrust bearing the same as a clutch would. I agree before anything is done a pan drop is in order.
Reply With Quote
  #8  
Old September 15th, 2017, 19:49
RCP Phx RCP Phx is offline
NAXJA Forum User
 
Join Date: Mar 2003
Location: Phoenix,Az
Posts: 11,636
Re: What causes "crank walk" to occur?

Yes the thrust bearing is the middle bearing!
Reply With Quote
  #9  
Old September 15th, 2017, 20:41
Hypoid's Avatar
Hypoid Hypoid is offline
NAXJA Member
 
Join Date: Jul 2006
Location: Golden, CO
Posts: 7,267
Re: What causes "crank walk" to occur?

Quote:
Originally Posted by BALTANAKT View Post
Or was it something else?
Is it possible that the engine is not original to your XJ?
__________________
The Lost Boys' motto: We don't know where we are going, but we'll be there for awhile...
Reply With Quote
  #10  
Old September 16th, 2017, 08:59
BALTANAKT BALTANAKT is offline
NAXJA Forum User
 
Join Date: Jul 2015
Location: Boulder, Colorado
Posts: 191
Re: What causes "crank walk" to occur?

Quote:
Originally Posted by Hypoid View Post
Is it possible that the engine is not original to your XJ?
I just went out and looked.

My Jeep was built 5/91.

Engine reads: I09MX27

Not sure what an "I" indicates. Trying to find some info on that. I'm assuming it means "1". If so, that I think it would mean the engine was built after the XJ.

Last edited by BALTANAKT; September 16th, 2017 at 09:12.
Reply With Quote
  #11  
Old September 16th, 2017, 10:03
Hypoid's Avatar
Hypoid Hypoid is offline
NAXJA Member
 
Join Date: Jul 2006
Location: Golden, CO
Posts: 7,267
Re: What causes "crank walk" to occur?

There is a cast date on the driver side, toward the back, just above the ribs that run the length of the block.

When I pulled the engine out of my '90, the block had a cast date in 1991.
__________________
The Lost Boys' motto: We don't know where we are going, but we'll be there for awhile...
Reply With Quote
  #12  
Old September 16th, 2017, 14:24
techno1154's Avatar
techno1154 techno1154 is offline
NAXJA Member
 
Join Date: Apr 2003
Location: In the islands
Posts: 2,276
Re: What causes "crank walk" to occur?

Quote:
Originally Posted by RCP Phx View Post
Yes the thrust bearing is the middle bearing!
Thanks for the info.

I have been in there once and that was in 2001 to change a rear main seal.
__________________
Patrick

#594
1996 XJ; 4.0L; AW4; NP231; SYE; D30 and D44; ECTED; 4.10 gears; 30X9.5 -15 BFG/AT/KO; 3" lift; Rusty's LCA; JKS ADJ UCA; Kevins ADJ Track bar; Drawtite Front Receiver; Dual Electric Fans; Dual Battaries.
Reply With Quote
  #13  
Old September 16th, 2017, 15:56
BALTANAKT BALTANAKT is offline
NAXJA Forum User
 
Join Date: Jul 2015
Location: Boulder, Colorado
Posts: 191
Re: What causes "crank walk" to occur?

Quote:
Originally Posted by Hypoid View Post
There is a cast date on the driver side, toward the back, just above the ribs that run the length of the block.

When I pulled the engine out of my '90, the block had a cast date in 1991.
Thanks!

Block reads: 83091
Vehicle built 05/91

Guess that's feasible.

Here's a video of the crank walk.

https://youtu.be/L4XN_mSOk_o
Reply With Quote
  #14  
Old September 18th, 2017, 06:37
Green XJ Jeep Green XJ Jeep is offline
NAXJA Member 4950
 
Join Date: Mar 2011
Location: Spanaway Wa
Posts: 553
Re: What causes "crank walk" to occur?

Your thrust bearing is shot.
Down and dirty quick fix is drop the pan and put new bearings in it. Keep in mind this is not the correct way to fix this.
The bottom end should be gone through since all the bearing surfaces are probably full of metal from the thrust bearing

Last edited by Green XJ Jeep; September 18th, 2017 at 06:41.
Reply With Quote
Reply


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Crank slides forward/backward 1/8" or so? BALTANAKT OEM Tech Discussion 6 May 4th, 2017 17:48
Found my "no bus" ,still crank and no start jeepdreamer OEM Tech Discussion 65 December 20th, 2015 17:44
"Any landing you walk away from,..." tbburg Non-Tech / Off Topic 12 July 11th, 2010 20:05
search for the "good" 258 crank the_bandit87 OEM Tech Discussion 4 October 7th, 2005 19:43


All times are GMT -7. The time now is 04:56.


Powered by vBulletin® Version 3.8.9
Copyright ©2000 - 2018, vBulletin Solutions, Inc.
NAXJA and NAXJA logo's Copyright NAXJA. All content/images Copyright NAXJA 1999-2014