Engine/Transmission (1998.5 - 2002) RPM @ speed??

[Bobalos]

what RPM are you guys spinning @ 70/75 MPH??? I have an auto truck with I think 3. 50's & 31 in tall tires (measured @ 31"), & its turning just over 2100 RPM.



I noticed it last night on the way home & it seems high to me. I tried to calculate out what it should be, but the numbers kept coming out all dumb & not making any sense.



thanks

Bob

 

[SnoKing]

Here is Klenger gear calculator. Go to the right for the auto. 2100 with 3. 56 should be around 75, with 31 inch tires.

http://www.klenger.net/dodge/general-reference/gear-speed-calculator.xls

SNOKING

 

[Bobalos]

thanks mucho.



Bob

 

[Bobalos]

Hey Snoking,



what kind of mileage you get with your truck??



thanks

bob

 

[SnoKing]

Hey Snoking,



what kind of mileage you get with your truck??



thanks

bob

Before or after new VP44? I just got 18. 6 combined driving on the new VP44. Have not driven it enough with the new pump, but it seems to have picked the mileage up about 2 MPG.



Got around 12. 5 at 19K with the trailer, before the new pump, it would be great if that went up a mile or two!! SNOKING

 

[SAndreasen]

i have 285 75 16 tires and 354 gears my rpm at 80 mph is dead on at 2000

 

[SAndreasen]

how do i change the numbers for axle ratio and tire size on the gear calculator

 

[Bobalos]

Before or after new VP44? I just got 18. 6 combined driving on the new VP44. Have not driven it enough with the new pump, but it seems to have picked the mileage up about 2 MPG.



Got around 12. 5 at 19K with the trailer, before the new pump, it would be great if that went up a mile or two!! SNOKING

I was getting 16 - 16. 5 while commuting & 19 - 19. 5 on the open freeway, it went down a bit to about 15 - 15. 5 & 18 - 18. 5 here recently. I just changed the VP & its the same. I was a bit surprised that it did not go back up to where it was or better.



the reason Im asking about the trans, is that Im concerned that maybe its slipping, I dunno how many miles are on it, but Im sure its days are numbered with the towing Ive done & now the HP increase.



thanks

Bob

 

[Bobalos]

how do i change the numbers for axle ratio and tire size on the gear calculator

when I downloaded it I was able to change the axel ratio, I could not do it on line.



Bob

 

[Dodoro]

My 2002 4x4, auto trans, 3. 55 gears, with 265/75 16 turns 2000 rpms at 77 / 78 mph empty I get 18. 5 - 21 on the highway and 16. 5 - 18. 5 combined.

 

[Bobalos]

Hmmmmmmmm, maybe its not so far off then.



thanks

Bob

 

[Schlickenmeyer]

2001 6 speed, 3. 54, at 70 mph I am running 1800 or so an even 2k rpm is like 72-73. seems happy there.