hello there, I'm new to this site so please bear with me if I'm posting this in the wrong place. Anyhow I have a 01 Silverado 2500hd 4x4 with the 8.1 litre and Automatic trans. I was coming home from work today and upon deceleration to slow to turn in my driveway, my truck made an awful grinding noise for approximately 30-45 seconds and the check engine light came on but now my truck will hardly pull itself. Anyone have any info on what may have happened or what I could check without a engine light scanner?? Any help appreciated, Thank you.

 

Got a Code: P1721
Anyone familiar with this??

 

Seems to be a common diesel code for the Allison trans. Does your truck have the Allison trans?

 

https://www.google.com/search?q=obdi...ntu&channel=fs

God bless
Wyr

 

Yes it has an Allison Tranny.