B&M 70226 TRANSKIT FOR GM 4L80E TRANSMISSION - Manual

1
Required Modification Instructions
1991+ GM 4L80E TransKit
Part Number 70226 and 70227
©2012 B&M Racing and Performance Products
9500866-00 Printed in the U.S.A.
The B&M TransKit you have purchased contains all the parts necessary to convert your stock transmissions to the
same basic specifications found in the famous B&M Transmission. This kit has been assembled with the assumption
that all of the stock parts needed will be reusable. However, upon disassembly of transmission that has excessive
mileage or has been abused, you may find that certain stock parts will have to be replaced. New parts may be
purchased from your GM dealer although in many instances you may wish to purchase used parts from a wrecking
yard or transmission repair shop. Before proceeding with the installation please read all of the B&M 4L80E Transpak
Kit installation instructions so you will be familiar with the series of steps required to install part of this kit. For detail
reference information purchase the ASTG 4L80E manual (Not provided by B&M). The following modifications must be
done before completing the B&M TransKit installation in order to prevent any issues from occurring.
‘
STEP 1. On center support, remove 2nd
from top sealing ring:
STEP 2. On Direct drum, remove center
lip seal:
STEP 3. Plug top hole (reverse port):
FOR HEAVY DUTY ONLY:
STEP 1. On pump, cross drill under “X”
with a .050”-.055” drill bit in order to tie
line and lube:
DUAL FEEDING FOR HEAVY DUTY AND HIGH PERFORMANCE:
Remove Sealing Ring
Plug Hole
Drill under “X”