Transmission Jerk

dank GN

BlackArts Automotive (661)993-8277
When i go from park to D my car jerks is this common?? I just put in a new stage 2 from lonnie at E/A.
 

dank GN

BlackArts Automotive (661)993-8277
The u joints looked good when i did my trans about a week ago. the clink sound kind of bothers me
 

LOT

Member
jerk or bang

They will do this if the waved steel in forward is replaced with a regular steel as some builders do. The waved steel acts as a cushion.I have done some that way and don't know as it hurts anything.
 

quickt

Well-Known Member
The internals rotate when in park. When you pull the trans into D gear oil is fed to the forward clutch. If the internals are still rotating as the wave plate bottoms this will cause the clutches stop the rotating parts abruptly. This results in a bump or clunk. This can and does happen with a wave plate and definitely with out one. (I use a wave plate in all my builds) Other things that aggravate the issue. Internal leaks that have been sealed up, Smooth forward clutches, Elevated main line at idle, tight converters, Elevated engine Idle speeds, TV Cable adjustment, TV Spring. The key to stopping the clunk is to stop the internals from rotating before the cushion spring (wave plate) bottoms. If that happens the engagement will be smooth. I have tried the sanding steel trick, using 2 wave plates, different clutches, Lowering the regulator spring tension and using larger boost valve. Results vary. Some positive and negative. In some cases the reliability of the forward clutch and the transmission are reduced. In my builds I choose to use more spring tension at the PR Valve v/s all boost valve for line rise. This will cause elevated idle pressure and with tight converter can aggravate engagement.
 
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