correct me if im wrong. . if you have a lower gear ratio then the drive shaft spins less per tire rotation. so thats less work on the engine right. if so that will save gas because the engine doesn'twork as much. so if your truck is mostly highway you said then staying at 3.55 might not be bad. thats just a lot of money to spend on just going to 3.92/3.90. if i was you i would wait and see how you like the new tires with your 3.55 gears then decide.once again if i was wrong i apologize

 

The lower gear ratio spins more times to get a turn on the wheels. The higher the number, the lower the gearing. So if you have 4.10:1 gearing, you get 4.1 turns for one axle turn, which leads to more turns of the gears for axle revolutions. Right now, with the 3.55:1 gearing, 3.55 times is how many turns of the gears it takes for 1 axle turn. Sounds dumb, but higher equals lower.

 

Thanks for responding to my thread Tim.
I have 285/75/r16's with standard gearing on my 98 1500 4x4. Just talked to my local offroad shop about gearing up to 4.10's and they said with tires no bigger than mine, it wouldnt make any difference. My truck is a daily driver, mostly interstate, and I hate the loss of power going up the hills on the commute (which didnt start until the tire upgrade). Maybe my mechanic is mistaken and I should upgrade anyway. Any idea what a reasonable price (material and labor) is for front and rear gears?

Food for thought

HammerNailKid

 

No, problem. From what I've gathered, anywhere between $1300 and $1500 seems to be ballpark for re-gearing. I priced 3.92/3.90 gears from Randy's ring and pinion...about $500 for the gears. Labor is the main cost...

I used a calculator today to see about the gearing and where it should be. For a stock tire size of 245 and 3.55 gearing, then bumping up to 285 tires, the gearing needs to be at least 3.82 to retain factory setup.

 

I've been thinking about re-gearing my truck, too. How difficult would it be to do the work yourself?

 

You have to take off all four wheels, pull the brake assemblies and remove the hubs, and then slide the axles out a little bit so it will release the gears. Then reverse the process... It isn't extremely difficult, but it can easily be screwed up if you are unsure of something.

 

Thats why I dont suggest newbs to playin with differentials.......Hell I'm even afraid to do it

 

Correct me if I'm wrong, but for the cost of gears being between $1,000 and $1,500 bucks couldn't you just do some work to the motor and get more power for when cruising or taking off, off the line??? For that money isn't it possible to get;

Mopar Performance heads?

or

A 3 stage race port and polish job done to the stock heads, modify the keggar, and have the runners of the intake port matched for a increase in flow to around 270cfm at about .5" of lift and while your at it, get that plenum plate thing fixed with a hughes kit plus some good Royal Purple oil in the diff, crankcase, and transfer case?

or

Brand new high flow exhaust system with headers and an intake?

or

A nice 4.04" bore with pistons out of 5.9 liter engine installed 180* in the opposite direction for a slight offset thus lowering friction while increasing compression along with a 4.00" stroke Eagle 4340 Forged steel crank for $800 from Summit and then a new cam to allow for the engine to breath properly for that extra displacement or possibly even what some people where talking about in another thread being 1.7 ratio roller rockers to allow the engine to breath easier ( https://dodgeforum.com/m_1200230/tm.htm ) thus making a 410 Stoker?

All that I'm saying is that for that amount of cash, there are quite possibly many other options as to how a person could really make the motor come alive seeing as how gears just allow the engine to reach into the Torque powerband faster whereas modifying the motor increases engine output power thoughout the entire powerband.

I say it's nice off the line, but not as nice as some high quality components to make the motor scream all the time.

 

Pardon the mistake. 4.04" pistons would be coming out of a 340, so in that case, 4.00" bore with all of the above for a 402 cubic inch smallblock, but then again, who says that the block can't be overbored .04" over to make that motor have 410 cubes?

And please don't forget the windage tray to keep the crank from sloshing around in the oil in the crankcase like the old Police edition LA engine smallblocks had if this avenue turns out to be the one of choice.

 

You could, but one of the main reasons for regearing is to gas mileage back up and to get the right ratio for your tires. The guy I work with is running 37's with 3.55 gearing and he gets like 7 mpg. If you get new gears, you don't necessarily need to do performance mods to get your low end back. Plus, it's less stressful on your entire drivetrain if you have the correct gearing.