What rear end ratio?

[Hounddog]

How can you tell what rear end ratio is? I have a 2007 3500 6. 7 with the 68RFE, DRW, quad cab long bed 4x4 with the anti spin diff. I couldn't find anything that tells me whether its a 4. 10 or 3. 93 ratio. The tach reads 1850 rpm at 75mph if that helps anyone. Thanks.

 

[redram3]

At that r. p,m , I would say 3. 73.

John

 

[gsbrockman]

3. 73's are standard equipment.



If you have the window sticker, and there's not an additional charge option listed for the 4. 10's, you will have the 3. 73's.



Greg

 

[klenger]

According the the gear charts on my website, you have 3. 373's.



go to page 3 of http://www.klenger.net/dodge/general-reference/gear-speed-calculator.pdf

 

[navyramman]

You need a GPS to get your right speed or closer then the truck MPH. The speed O metters are set about 3 to 4 MPH faster then you are going (you know them bean counters and lawers trying to CYA). 3. 73's will give you around 2000 rpm = 79 mph on your truck and gps is 76 mph. All numbers are about, It is hard to watch and drive at the same time, and things can be off on each truck + - 1 or 2 mph or 100 - 200 RPM's. We are driving down the road, not Nascar. The 5. 9's were a round 2000 rpm = 70 mph about (I think). That is what I got on my 03, with 3. 73's and it changed +4 or 6 mph with my 285's on it too.

 

[HBarlow]

Comparing my truck speedometer to the speed over the ground as measured by my Garmin Street Pilot 2720 my speedometer is only 0. 5 to 1. 0 mph fast. Not bad actually.



Harvey

 

[Hounddog]

All, thanks for the replies. No I don't have an additional charge on window sticker. I thought the 4. 10s were an order option but wasn't sure if it came with the tow package. Loving my truck. This weekend's trip (350miles) netted 17. 7mpg. Not bad for only having 600mi on the truck.

 

[TKeeler]

How can you tell what rear end ratio is? I have a 2007 3500 6. 7 with the 68RFE, DRW, quad cab long bed 4x4 with the anti spin diff. I couldn't find anything that tells me whether its a 4. 10 or 3. 93 ratio. The tach reads 1850 rpm at 75mph if that helps anyone. Thanks.

I am running right at 2,000 RPM at 70 MPH with the 4. 10's axles.