Hi guys love the site, learn new stuff everyday here. I ordered a 1500 Laramie with a build date of March 29th.

I've never own a truck but always wanted one so getting pretty excited about it. Anyways I done some research about the gears 3.55 and 3.92, just wanted some last minute ideas to it.

I probably will never tow anything excepted maybe a sea-doo, I drive highway to work everyday and travel alot. Live in the Detroit/Windsor area for snow which isn't that much compare to everywhere else around us.

So should I stay with the 3.55 or move up to 3.92? Do I need the 3.92?

Help please!!

 

If you are not going to play to rough in it, or going to work it hard absolutely go with the 3.55's. This will improve your highway mileage a little. The only caveat is if you want an LSD rearend, which is only available in the 3.92. Hope this helped.

 

not only that, if you have 3.55 gears already, the dealership isnt going to swap them. from what i was told at the dealership is that each truck is programmed with that particular gear set. and they say once it is done, it is done. you could go with aftermarket from another company, but then it will mess with your warranty.

 

Nah that's a bunch of BS you could swap gears everyday and it wouldn't effect the truck's programming. I'd go w/ the 3.92's if I was ordering one new.

 

This is something that relies precisely on your type of driving.

We have the 3.21 diff (which most everyone here will say is a "dog" or too slow, whatever) but for what we do (95%+ highway driving) it's the best option. We hardly ever tow, and when we do it's a motorcycle on a trailer (so maybe 1000lb's max).

The 3.21 diff gets GREAT highway mileage but yes, it will cause your around town mileage to suffer, and yes it is more than likely slower off the line than the other diffs.

But, if all you do is sit on the highway at 70-80mph, then this is the diff for you. The diff gears the truck so that 2nd gear is almost perfectly in line with the governor. The truck is limited to 105mph, and the truck is about 200-300RPM's away from redline in 2nd gear when it hits that limiter. Makes for great passing at highway speeds. The truck also sits at less than 2000RPM at 85mph, which is great for mileage.

I averaged 18.2mpg going about 90mph for 10 hours with some mixed in city driving (we do have a tonneau though). We got 23.6mpg going 70mph on the freeway only.

If you do a lot of combined (like 50/50 hwy/city or even 70/30) you might want to opt for a 3.55 diff. But if you do a TON of highway driving, then the 3.21 diff might be something you want to look into.

If you do primarily city driving, the the 3.92 might actually get you better mileage.

This is my one complaint about the truck. Other than go through all this BS with the diff ratio's, they should have thrown a 6 speed into the truck and not worried about the gearing. With a 6th gear we could have had the first 3 gears as short as a 3.92 diff and the final drive still as tall as a 3.21 diff.

 

I would go with the 3.92 because of the LSD. I primarily drive in the city, but do have a 250 mile drive to a friends cabin that I am at almost every weekend. My 06 with 3.92's did 21.5 MPG going 65-70 and it was a quad cab hemi 4x4 - I am happy with that for a truck and that it will have the extra umph I want around town. Also, the LSD makes a HUGEEEE difference in the snow, when I had an open diff on my 06 I was in and out of 4x4 ALL THE TIME, when I went to LSD it was night and day. Just my .02

 

It is the final ratio that matters. My general rule on these trucks, towing or not.... Factory 17" with factory size rubber, 3.55s. Factory 20" with factory size rubber, 3.92.

 

My truck will be in the shop all day Thursday getting 4.10s, Aurburn LSD, and the R/T torque converter.

 

I agree 100%.

Also if you are questioning it now that means you probably want it. It is only $375 upgrade from the dealer and it will cost about $1500 if you decide you want it later. Also you say this is your first truck, It is only a matter of time before that Sea-doo turns into a 20 ft Bowrider. Then you will wish you had the 3.92's. I say get the 3.92's if you are ordering it. I got lucky and the truck I bought came with them.

 

LOL, buying the emblem as well?