M-20 Trans Install not fitting
Thread Starter
5th Gear
Joined: Mar 2005
Posts: 5
Likes: 0
M-20 Trans Install not fitting
I have a 72 vette which I just purchased a GM performance 350 w/290hp motor. I have a muncie 4 speed which I am trying to install. I have done this on a couple of other chevys but for some reason When I install the trans the input shaft is coming within a half inch or so of going in. The splines mesh up fine it just seems that when it reaches the pilot bushing it stops. Does anyone know if the pilot bushing that is installed on this particular motor is a different size. I am doing this in my garage on my back so it is pretty tough trying to get it lined up but I feel like the pilot bushing is too small is this possible? Thanks for any helpful info
Melting Slicks
Joined: Mar 2006
Posts: 3,342
Likes: 7
From: Connecticut
Did the bushing come with the clutch kit?
Im pretty certain all Muncies and Borg Warners had the same diameter input shaft stem which would mean that the ID of any pilot bushing/bearing should be one size only. A litle grease on the end of the shaft helps too.
Is the fork mounted correctly? Is the throw out bearing backwards?
I trust you know what your doing but we all make mistakes.
I know its a very tight fit under there and the transmissision needs to be rotated a bit to get it in.
Seeing you already have the input shaft into the clutch disc this is probably not an issue anymore but could it be catching on something?
Im pretty certain all Muncies and Borg Warners had the same diameter input shaft stem which would mean that the ID of any pilot bushing/bearing should be one size only. A litle grease on the end of the shaft helps too.
Is the fork mounted correctly? Is the throw out bearing backwards?
I trust you know what your doing but we all make mistakes.
I know its a very tight fit under there and the transmissision needs to be rotated a bit to get it in.
Seeing you already have the input shaft into the clutch disc this is probably not an issue anymore but could it be catching on something?
Pro
Joined: Sep 2002
Posts: 546
Likes: 0
From: Pinellas Park FL
Sounds like an issue with the pilot bushing / bearing. Did you replace it before installing the tranny? If not, I would suggest you remove it and replace with a new one. They are inexpensive and should be changed when ever the tranny is replaced.
Le Mans Master
Joined: Mar 2001
Posts: 6,640
Likes: 287
From: Ann Arbor Michigan
My guess is that the clutch disc is not lined up with the pilot bushing. Push the clutch in then rotate the output shaft (trans in gear) while pushing it forward. 3 times out of 4 I had to do this even though I used an Alignment tool. Trans was about a 1/2" back just like yours.
Drifting
Joined: Jan 2006
Posts: 1,832
Likes: 38
From: Cedar,BC
The pilot bushing is the same size for all the different combos,maybe it got slightly distorted or burred when driven into the back of the crank.If not,check your disc alignment again,it sounds like it maybe off a bit.Also check to make sure the transmission front bearing retainer is the correct OD for the belllhousing if these parts haven't been used together before.
