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merdas
10-12-2007, 10:15 PM
Hallo everybody. I am a new, proud owner of the 2007 dodge Sprinter. One thing I would like to change is ring and pinion on the rear axle for say 3.55 to lower the RPM on highway speeds. I think that 3000 RPM's at 75 MPH is bit to high, the engine has enough power to pull with higher gear ratio. What do you all think about this idea and is it possible to get ring and pinion for this axle? Thanks for all input, Mark
:cheers:

sikwan
10-12-2007, 10:37 PM
What is your current gearing?

From this link...

http://sprinter-source.com/forum/showpost.php?p=420&postcount=2

...you can download the parts list.

The only ratios available according to the list are 3.92, 4.10, 4.72, 5.10. The last two are probably for the 3500's. If you're going from 4.10 to 3.92, you might be lucky enough to use the original carrier. I don't know what the ratio cutoff is for the carrier.

I don't know if you can get a 3.55.

merdas
10-13-2007, 01:02 AM
What is your current gearing?

From this link...

http://sprinter-source.com/forum/showpost.php?p=420&postcount=2

...you can download the parts list.

The only ratios available according to the list are 3.92, 4.10, 4.72, 5.10. The last two are probably for the 3500's. If you're going from 4.10 to 3.92, you might be lucky enough to use the original carrier. I don't know what the ratio cutoff is for the carrier.

I don't know if you can get a 3.55.

I have 4.10 now, I am not sure if 3.92 will make that much of a difference. I would like to go lower.

merdas
10-13-2007, 01:07 AM
Thanks for the link -sikwan-.
:thumbup:

Sprinter
10-13-2007, 07:33 PM
Merdas, I face the same issue of too high RPM's on the highway. In the suburbs at 50-55 MPH I get beautifull 24+ mileage so I am very happy, especially after reading others posts (under 20)

Problem starts above 2400 RPM on the highway (which is most in my case) and 23-24 MPG is history. I was also looking to change aspect ratio to lower number but I guess I was going in the wrong direction.
I was looking for the whole new axle, well that is $4000, no labor so I am not into this solution anymore.
I didn't know You can replace just the inner parts (ring, pinion?) to get lower ratio. Even going down to factory 3.92 should be enough for me, that's always 200-300 rpm's less, besides I don't go over 75, seldom over 70 so I should be able to squize 24, maybe 25 MPG. Too bad I didn't know about aspect ratio 4 months ago, when I was buying the van and salesman is the last person to tell (wonder if he knows?) I found this forum little too late, but better late than never, it already has helped me to get to 24mpg from initial 18! and I think it's not the end yet

Anyway, please let me know if You succed changing this pinion so I can try the same

merdas
10-13-2007, 08:08 PM
Merdas, I face the same issue of too high RPM's on the highway. In the suburbs at 50-55 MPH I get beautifull 24+ mileage so I am very happy, especially after reading others posts (under 20)

Problem starts above 2400 RPM on the highway (which is most in my case) and 23-24 MPG is history. I was also looking to change aspect ratio to lower number but I guess I was going in the wrong direction.
I was looking for the whole new axle, well that is $4000, no labor so I am not into this solution anymore.
I didn't know You can replace just the inner parts (ring, pinion?) to get lower ratio. Even going down to factory 3.92 should be enough for me, that's always 200-300 rpm's less, besides I don't go over 75, seldom over 70 so I should be able to squize 24, maybe 25 MPG. Too bad I didn't know about aspect ratio 4 months ago, when I was buying the van and salesman is the last person to tell (wonder if he knows?) I found this forum little too late, but better late than never, it already has helped me to get to 24mpg from initial 18! and I think it's not the end yet

Anyway, please let me know if You succed changing this pinion so I can try the same


In what way the forum helped you to get the lower gas millage?

Sprinter
10-13-2007, 11:25 PM
To get there I did few things. First of all, at my initial panic of getting only 18MPG I was told to let it brake in and wait until 10k miles. I have 20k on the clock now and I really started to see improvement after 7-8k of easy driving.

I also used upper cylinder lubricant/injector cleaner RL-2 (suggested by Altered Sprinter on another forum) That was a big jump not only in mileage but even in engine sound and power, I use it all the time although I just ordered RL-3 winter with cetane booster

Then I was told to pay more attention to the fuel brand and I stopped buying the cheapest diesel available. I switched to Shell fuel which suppose to be the cleanest one in US

I don't let it idle for too long, I just shut it off. Finally, I inflated front tires from 47 to 70PSI and of course I don't drive it like I would my old gas Mercedes, I drive it like it's diesel.

Easy. And here I am, 24+ MPG still looking for more.

please remember to let me know about Your axle project
My dealer knows nothing about Sprinters (even dough it's biggest seller in Midwest) Whatever I ask them reply is " I don't think that can be done..."

merdas
10-14-2007, 04:36 PM
To get there I did few things. First of all, at my initial panic of getting only 18MPG I was told to let it brake in and wait until 10k miles. I have 20k on the clock now and I really started to see improvement after 7-8k of easy driving.

I also used upper cylinder lubricant/injector cleaner RL-2 (suggested by Altered Sprinter on another forum) That was a big jump not only in mileage but even in engine sound and power, I use it all the time although I just ordered RL-3 winter with cetane booster

Then I was told to pay more attention to the fuel brand and I stopped buying the cheapest diesel available. I switched to Shell fuel which suppose to be the cleanest one in US

I don't let it idle for too long, I just shut it off. Finally, I inflated front tires from 47 to 70PSI and of course I don't drive it like I would my old gas Mercedes, I drive it like it's diesel.

Easy. And here I am, 24+ MPG still looking for more.

please remember to let me know about Your axle project
My dealer knows nothing about Sprinters (even dough it's biggest seller in Midwest) Whatever I ask them reply is " I don't think that can be done..."


Thanks for the tips and I will keep you posted.

:thumbup:

sikwan
10-14-2007, 06:59 PM
One thing you could do is maybe change the tire size to a large diameter, although I should calculate the ratio to see whether it would be doable (fit). :smirk:

Going form a 4.10 to a 3.55 is a 13.4% change is diameter. For a 245/75-16 (30.4) tire size, that would mean something close to ~34.5 inches in diameter.

Or you can regear to a 3.92 and change to size a smaller than 34.5 inches, but larger than 30.4 inches.

Or you can just drive slower. :smilewink:

Sprinter
10-18-2007, 01:44 AM
3.92 ring and pinion is $1100 at my dealer, no labor estimate yet as service manager had no idea. If it's gonna be below $1500 all together I think I am gonna do it

jdcaples
10-18-2007, 04:47 AM
( in an earlier post )
My dealer knows nothing about Sprinters (even dough it's biggest seller in Midwest) Whatever I ask them reply is " I don't think that can be done..."
(and more recently)

3.92 ring and pinion is $1100 at my dealer, no labor estimate yet as service manager had no idea. If it's gonna be below $1500 all together I think I am gonna do it


You trust this shop to pull apart your 24 mpg Sprinter? I'd recommend you look for a more confident (competent?) shop and not get too greedy about wanting service in close proximity to your normal stomping grounds.

Don't get me wrong: I think it'd be wonderful if you could find someone that is able to execute the transition, including the software modifications if the drive train's electronic parts need different programming.

If a dealership service manager says there's little Sprinter technical talent in the service bay, consider taking your ride elsewhere for surgery.

-Jon

Sprinter
10-23-2007, 10:40 PM
Yeah, You're right about this shop Jon, although the most important person there (mechanic) supposted to be good, with long time experience with diesel, guy is from Europe

Anyway I would rather change the wheels. I went to local discount tires and they told me there is no way I am gonna find it. There are tires (245/75/17) no problem Contitrac, Michelins and other but rims... 6.130 54 offset very unusual, they've never seen anything like it