Engine/Transmission (1994 - 1998) tensioner?

[The patriot]

I did my tensioner a while ago, only have 135K on the truck
I look at the a/c comp pully & the belt is off the pully by1 rib. so I put it back on.
Today ....same.
Does this sound like the tensioner?
Where's the cheapest place to get a cummins part?
tia

 

[Freebore]

I bought a Dayco tensioner from Rockauto for my 07 5.9 and it is an exact duplicate of the one that came on the truck, even made in the USA, quite sure it's the same one that comes in a Cummins box and I believe it was $79.00

 

[The patriot]

Thanks. Mone is $44-$66 @ rock
Same symptoms?

 

[GAmes]

https://www.genosgarage.com/product/gates-38157-belttensionerassembly/belts

I have one of these, I can't tell you how many miles are on it, but it is over 300k for sure. I replaced it because of the belt coming offf the side of the pully, same symptoms as yours.

 

[The patriot]

Just saw your reply.
This is already my 2nd one @136 K miles.
I replaced the first because I didnt like a plastic pulley IIRC.
Thanks.