My E99 DRW F350 with dana 80 POSI or LS? It has a very low speed hop or shudder when starting off in a turn. I had the driveshaft out and did the hanger bearings and u joints but still get the shudder as starting off in a turn. No problems or noises on highway. Is this just the posi or something else. I just picked up the truck few months ago and going through it. I just replaced the torque converter as it had the E99 noisy converter

 

I don't have an answer to your problem but can I ask what a E99 is?

 

It is a early 99 not a 99.5 year

 

Thanks. Didn't know there was a difference

 

Mine had a shutter when turning when I first bought it. It was more noticeable in reverse.
After a synthetic fluid change and two tubes of Trans X limited slip additive (advance auto has it) the shutter slowly went away never to return.

I've heard that the diff fluid that claims to have LS additive does not contain enough of the additive. It's possible that the The previous owner changed the fluid and was not aware of this.
I've been running Mobil one with Trans X and haven't had any issues for the past 4 years.

The rear is a LS.

 

I am thinking same as I was researching. He must have changed fluid and no additive

 

I ran the code F2 on door and it is a LS 4:10 do I will try the friction modifier