LS Swap Vibration at highway speeds
 

Hey guys, I swapped a LS 5.3 gen 3 with 4L60 BP engine harness in my 72 c10. Here is my issue. When I drive the truck from when it was sitting so the trans isn’t completely warmed up, drives like a dream, no vibration at 70-80. But when I have been driving for a while and all is warmed up (trans 185 / motor 210) and I stop and turn it off and fire it back up, I get a vibration at 60+ it seems. Has anyone ever had this before? Does that make sense? Been dealing with it since I did the swap. Supposed to be a rebuilt 4L60 so I am stumped. Any info would be greatly appreciated. Thanks! Neil

Re: LS Swap Vibration at highway speeds
 

When it starts vibrating, can you try slipping it in neutral ..if its possible ,while its still rolling..and see if it still vibrates?
Does sound odd it only does it when warm and after a recrank.

Re: LS Swap Vibration at highway speeds
 

Thanks for the advice, will definitely try that. Thanks!

Re: LS Swap Vibration at highway speeds
 

Could it be an engine misfire? I know its possible for an engine to run great and then develop a miss once warmed up. Maybe it's running on 7 once warmed up and creating a shake. Just a thought. Hopefully it's an easy fix.

Re: LS Swap Vibration at highway speeds
 

One more thing. I have never had a vibration issue from the many 4l60e's I have owned but I did have shift solenoid issues in my s10 a few years ago. It was stuck in 3rd gear and I had to drop the pan to change the two shift solenoids. I realize that has nothing to do with your problem but maybe one of the other solenoids in the transmission is acting goofy. I have had hanger bearings cause a shake but that cant be it because those always happen at the same time and speeds.

Re: LS Swap Vibration at highway speeds
 

I have been thinking about getting it retuned. I had not thought of that being the issue, I will check it out. Thanks!

Re: LS Swap Vibration at highway speeds
 

A bad torque converter can cause vibration.

Re: LS Swap Vibration at highway speeds
 

The problem is we are just throwing darts at the wall at this point. Hopefully its something simple.

Did you ever clear the adaptive learning on the pcm for the transmission? I doubt it’ll fix this but I’m curious to know if it’s necessary or if it’ll cause any problems if you don’t.
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