Re: Twin Ultramatic Transmission oil pan bolts

Posted by Redhexagon On 2023/5/23 5:49:31

A lifetime transmission rebuilder friend of mine runs transmission pan bolts down until they are just barely snug then turns them all 1/4 turn more regardless of the torque.

I thought it was nonsense until I thought about it this way:

The goal is to produce the correct amount of "squish" on the gasket. What if the gasket is wider in some areas that others? Those wider areas would squish less than the narrower areas if the bolts were all torqued the same. It's all related to surface area and pressure per square inch. It would take more turns of the bolts in the narrower areas to reach the same torque.

By running all the bolts down snug, then turning them all the same amount, you produce the same amount of squish across the entire gasket.

Then it made sense to me.