Vibration after Th400 install. - JeepForum.com
Search  
Sign Up   Today's Posts
User: Pass: Remember?
Advertise Here
Jeep Home Jeep Forum Jeep Classifieds Jeep Registry JeepSpace Jeep Reviews Jeep Gallery Jeep Clubs Jeep Groups Jeep Videos Jeep Events Jeep Articles
Go Back JeepForum.com > Models > Jeep CJ Forum > Vibration after Th400 install.

Introducing MONSTALINER™ UV Permanent DIY Roll On Bed LineRubicon Express Suspensions from CCOR 706-207-4140Smittybilt Hard Tops @ Oconee Off-Road! 706-534-9955

Reply
Unread 08-24-2014, 05:58 PM   #1
skizriz
Web Wheeler
 
skizriz's Avatar
1978 CJ7 
 
Join Date: Jun 2011
Location: , Pa
Posts: 3,581
Vibration after Th400 install.

Been having vibration issues after a recent rebuild of my TH400. I've had it off and apart with no issues before, but after a recent rebuild, new flex plate, and new torque converter, I am having vibration issues.
I unbolted everything today, and slid the trans back about 1/2", and rebolted everything up to make sure nothing was crooked.
Everything seems fine. The torque converter has about 1/16 gap between the mounting pads and flex plate. Spins freely when unbolted. The T/C bolts start right in with very little effort to line the holes up.
The vibration isn't driveline, it does it with it in park, at about 1,500 to 2,500 rpm.

What might I be missing here??

__________________
78 CJ7 258 TH400/Dana18 SOA/stock YJ springs 35" General Grabbers.
skizriz is offline   Reply With Quote
Unread 08-24-2014, 06:27 PM   #2
skizriz
Web Wheeler
 
skizriz's Avatar
1978 CJ7 
 
Join Date: Jun 2011
Location: , Pa
Posts: 3,581
Wonder if it could be the crank bushing missing? I never even noticed whether there is one in there or not. The converter seems to slide in very easy, almost too easy. And I can push up on the converter slightly to start the bolts in.
__________________
78 CJ7 258 TH400/Dana18 SOA/stock YJ springs 35" General Grabbers.
skizriz is offline   Reply With Quote
Unread 08-24-2014, 06:44 PM   #3
RenoF250
Registered User
1985 CJ7 
 
Join Date: Sep 2011
Location: Foresthill, CA
Posts: 1,363
Quote:
Originally Posted by skizriz View Post
Wonder if it could be the crank bushing missing? I never even noticed whether there is one in there or not. The converter seems to slide in very easy, almost too easy. And I can push up on the converter slightly to start the bolts in.
So you are saying the TC can move relative to the crank when loose? That is not good, it is quite heavy and if not centered would certainly vibrate.
RenoF250 is offline   Reply With Quote
Unread 08-24-2014, 06:53 PM   #4
skizriz
Web Wheeler
 
skizriz's Avatar
1978 CJ7 
 
Join Date: Jun 2011
Location: , Pa
Posts: 3,581
Quote:
Originally Posted by RenoF250 View Post
So you are saying the TC can move relative to the crank when loose? That is not good, it is quite heavy and if not centered would certainly vibrate.
I did notice that I pushed up on it a hair to get the first t/c bolt started. Got me wondering if the bushing came off with my old t/c (turned it in for core), or it never had one, and I was lucky before and it didn't vibrate without it.

I never even knew about the bushing until I started looking into the problem. Got me wondering now.
__________________
78 CJ7 258 TH400/Dana18 SOA/stock YJ springs 35" General Grabbers.
skizriz is offline   Reply With Quote
Unread 08-24-2014, 08:12 PM   #5
RenoF250
Registered User
1985 CJ7 
 
Join Date: Sep 2011
Location: Foresthill, CA
Posts: 1,363
Quote:
Originally Posted by skizriz View Post
I did notice that I pushed up on it a hair to get the first t/c bolt started. Got me wondering if the bushing came off with my old t/c (turned it in for core), or it never had one, and I was lucky before and it didn't vibrate without it.

I never even knew about the bushing until I started looking into the problem. Got me wondering now.
Have you run it with the cover off to see if the TC is centered?
RenoF250 is offline   Reply With Quote
Unread 08-24-2014, 08:13 PM   #6
RenoF250
Registered User
1985 CJ7 
 
Join Date: Sep 2011
Location: Foresthill, CA
Posts: 1,363
You could take the plugs out and turn it over with the starter and use a micrometer to get it centered.
RenoF250 is offline   Reply With Quote
Unread 08-25-2014, 01:24 AM   #7
dg6772
Registered User
1986 CJ7 
 
Join Date: Feb 2011
Location: Muskegon, Michigan
Posts: 1,471
AMC TH400 has a torque converter bushing? The standard GM does not. Just fits into the end of the crank. I would assume the same......

Dave in Muskegon using JeepForum
dg6772 is offline   Reply With Quote
Unread 08-25-2014, 01:39 AM   #8
skizriz
Web Wheeler
 
skizriz's Avatar
1978 CJ7 
 
Join Date: Jun 2011
Location: , Pa
Posts: 3,581
Quote:
Originally Posted by RenoF250 View Post

Have you run it with the cover off to see if the TC is centered?
That i did. Could see it wobbling some. I have no idea what is a normal amount to compare to. Ill do it again after work today, and post some video of it.

Sent from my HTC One SV using JeepForum
__________________
78 CJ7 258 TH400/Dana18 SOA/stock YJ springs 35" General Grabbers.
skizriz is offline   Reply With Quote
Unread 08-25-2014, 03:55 AM   #9
skizriz
Web Wheeler
 
skizriz's Avatar
1978 CJ7 
 
Join Date: Jun 2011
Location: , Pa
Posts: 3,581
Quote:
Originally Posted by dg6772 View Post
AMC TH400 has a torque converter bushing? The standard GM does not. Just fits into the end of the crank. I would assume the same......

Dave in Muskegon using JeepForum
From what i understand the AMC cranks will fit the 727 and used a bushing for the th400.

Sent from my HTC One SV using JeepForum
__________________
78 CJ7 258 TH400/Dana18 SOA/stock YJ springs 35" General Grabbers.
skizriz is offline   Reply With Quote
Unread 08-25-2014, 04:04 AM   #10
grasmo
Registered User
1982 CJ5 
 
Join Date: May 2014
Location: tallahassee, florida
Posts: 205
there shouldn't be a 'bushing'. it would serve no purpose seeing how the tc/flexplate/cs all bolt together.....I have heard that re-clocking the tc in relation to the flex plate removes vibration sometimes.
grasmo is offline   Reply With Quote
Unread 08-25-2014, 05:07 AM   #11
dg6772
Registered User
1986 CJ7 
 
Join Date: Feb 2011
Location: Muskegon, Michigan
Posts: 1,471
Quote:
Originally Posted by skizriz View Post

From what i understand the AMC cranks will fit the 727 and used a bushing for the th400.

Sent from my HTC One SV using JeepForum
Damnit. ....learned something again.....thanks! Lol

Dave in Muskegon using JeepForum
dg6772 is offline   Reply With Quote
Unread 08-25-2014, 05:08 AM   #12
dg6772
Registered User
1986 CJ7 
 
Join Date: Feb 2011
Location: Muskegon, Michigan
Posts: 1,471
Quote:
Originally Posted by grasmo View Post
there shouldn't be a 'bushing'. it would serve no purpose seeing how the tc/flexplate/cs all bolt together.....I have heard that re-clocking the tc in relation to the flex plate removes vibration sometimes.
Good idea....I've heard of that before...

Dave in Muskegon using JeepForum
dg6772 is offline   Reply With Quote
Unread 08-25-2014, 06:05 AM   #13
skizriz
Web Wheeler
 
skizriz's Avatar
1978 CJ7 
 
Join Date: Jun 2011
Location: , Pa
Posts: 3,581
Quote:
Originally Posted by grasmo View Post
there shouldn't be a 'bushing'. it would serve no purpose seeing how the tc/flexplate/cs all bolt together.....I have heard that re-clocking the tc in relation to the flex plate removes vibration sometimes.
I set out to do that yesterday, but couldnt get the trans back far enough to get a rotation out of the t/c. Those darn nubs on the flex plate keep it from rotating fully like a normal t/c would do when unbolted.

Sent from my HTC One SV using JeepForum
__________________
78 CJ7 258 TH400/Dana18 SOA/stock YJ springs 35" General Grabbers.
skizriz is offline   Reply With Quote
Unread 08-25-2014, 08:49 AM   #14
CSP
Registered User
 
Join Date: Aug 2002
Location: Colorado
Posts: 12,300
Quote:
Originally Posted by grasmo View Post
there shouldn't be a 'bushing'. it would serve no purpose seeing how the tc/flexplate/cs all bolt together.....I have heard that re-clocking the tc in relation to the flex plate removes vibration sometimes.
Yet AMC did install a thin bushing into the back of the crank when used with the TH400. Even with bolts holding things together there can be enough leverage at RPM to have runout at the front of the convertor.

Bolt holes are far from precise when it comes to rotating assemblies as well.

Novak sells replacement bushings.
CSP is offline   Reply With Quote
Unread 08-25-2014, 08:51 AM   #15
jblue1555
Member
1979 CJ7 
 
Join Date: Aug 2006
Location: Topeka Kansas
Posts: 262
If the sleeve isn't in the crank you have to pull the trans and put one in it. 727 fits without.
jblue1555 is offline   Reply With Quote




Jeep, Wrangler, Cherokee, Grand Cherokee, and other models are copyrighted and trademarked to Jeep/Chrysler Corporation. JeepForum.com is not in any way associated with Jeep or the Chrysler Corp.