A500/42RH/RE, 44RE, A518/A618, 46 & 47 RH/RE Units

Overdrive Piston Not sitting Flat after Installation

After installation of the OD piston (mainly on 98 up units) make sure the piston

is sitting flat using a straight edge. 

(as pictured below)

(click on image for larger display)

Some late model OD pistons will sit higher on one side than the other as displayed in image below with #1 arrow. This causes the OD shim thickness to change unless you are still measuring using the factory method. Most builders have come up with faster & easier ways to measure the clearance but they are affected if you try to install this late model piston. Below is explanation on how to easily get the piston to sit flat.

(click on image for larger display)

Picture below shows the difference between the 2 OD pistons in the area marked w\red arrows

(click on image for larger display)

Picture below shows the problem that hits the piston if the area shown above is filled in. Remove the problem bolt, chuck it up in the lathe and cut the top off a little or you can use a grinder if you don't have access to a lathe. Cut the top of the bolt until it's smooth like the picture displayed below, then reinstall the bolt and the piston will sit flat & not cause you any problems.

(click on image for larger display)

 

(click on image for larger display)

 

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