3.92s Engine RPM at 65mph?

[JonF]

I bought my 2011 1500 used a bit over a month ago. The window sticker said the truck had 3.55s but I downloaded the build sheet last night and it said it has 3.92s. On the highway at 65mph I'm running right at 1800 engine rpm. I had a 2013 1500 for about 3 months and it had 3.55s but I don't remember the engine rpm on the highway. Does this RPM sound right for 3.92s and stock P275/60R20 tires?

 

[NYCruiser]

I have 3:55's and I'm over 70 mph I think at 1800. I'd trust the build sheet over the used car dealer's window sticker.

 

[RLJ10X]

Hey Jon, my truck has 4.10s, and it turns 2000 rpm at 70. So I think you are correct in thinking you have the 3.92. I'm sure some one who really knows will chime in soon.

 

[Gymkata]

Yes, you have 3.92 gears if the 0.67 final drive ratio I looked up was correct.

 

[blackbetty14]

Crawl under the back of the truck and look at the sticker on the driver side axle tube. Will have the gear ratio printed on it very clearly... as long as there wasnt a gear swap.

That being said I'm at about 1800 at 70-75mph with my 3.55 and 6speed.

 

[JonF]

Thanks guys. I did pretty much trust the build sheet. I didn't really trust the used car sticker because it also said manual seat adjusters but I have the 10 way power drivers seat too. So... 3.92s... I think I see a little taller tire in my future when the stockers are done.