4:10 Gears

ROADHAWG · **Posted:** Mon Jul 28, 2008 10:21 pm

I am sure this has been asked before but here goes anyways. I am running a Frankenlift II with 265/70/16 BFG AT's and an ARB bumper. I find my Jeep is lacking a lot in the power department particularly if i am towing my utility trailer. I really want to add a rock lizard rear bumper, sliders and a winch but I am worried about how much more power I stand to lose with all that added weight. I am wondering if anyone here has done a 4:10 swap and what kind of improvements if any a guy could exoect from this. Thanks.

Dje Ryu · **Posted:** Mon Jul 28, 2008 11:09 pm

Do it, you won't be sorry. From what I've heard, anyway. It's the lowest gear set you can get for the D30A and you're already at the tire size recommended for it. Can't hurt mileage any. Call Reider Racing for the gears (also only read that).

dieselenthusiast · **Posted:** Tue Jul 29, 2008 3:14 am

ROADHAWG wrote:

I am sure this has been asked before but here goes anyways. I am running a Frankenlift II with 265/70/16 BFG AT's and an ARB bumper. I find my Jeep is lacking a lot in the power department particularly if i am towing my utility trailer. I really want to add a rock lizard rear bumper, sliders and a winch but I am worried about how much more power I stand to lose with all that added weight. I am wondering if anyone here has done a 4:10 swap and what kind of improvements if any a guy could exoect from this. Thanks.

The more weight you add, the more you're killing your KJ. 4:10's will help, but not solve the horsepower problem. I'm torn also.

tjkj2002 · **Posted:** Tue Jul 29, 2008 8:59 am

Well I was in your same situation,my KJ went from 4000lbs to 5500lbs due to armor being added.I installed 4.10's with my 265/75's and it was a world of difference,almost back to stock power.4.10's is not the correct gear ratio for my tires/weight and the KJ's powerband,4.56's would be the best choice but are not possible with our D30A's.For 245/75's and heavy armor, 4.10's would be just about right.

That's the biggest reason for me doing a SFA swap,being able to gear correctly--------35" tires and 5.13 gears.

jsc7002 · **Posted:** Tue Jul 29, 2008 12:07 pm

When I called Reider Racing they told me it would be $572 and that was including everything the gears and master overhaul for front and rear, so thats what Im going to be doing here real soon

dieselenthusiast · **Posted:** Thu Jul 31, 2008 1:02 am

jsc7002 wrote:

When I called Reider Racing they told me it would be $572 and that was including everything the gears and master overhaul for front and rear, so thats what Im going to be doing here real soon

That's a good price, let us know how much of a difference it made.

JL Rockies · **Posted:** Thu Jul 31, 2008 9:30 am

After installing my 4.10 gears, I just burned through my first full tank of fuel. I am happy to report that my economy increased 1.5 mpg. Any increase is OK but to put things in context; I was down 8 mpg from stock after all the weight and lift was added. Now I am rockin down the road at 20 mpg......yeah baby!

tommudd · **Posted:** Thu Jul 31, 2008 9:55 am

I haven't done mine yet :twisted:

but I know form past experience that it will make a big difference in not only performance but also a little better fuel ecomony.
Mines the same as ROADHAWG, when I have the trailer on and down "in the hills" my power is gone!
But soon I hope to have 4.10s installed :twisted:

jsc7002 · **Posted:** Thu Jul 31, 2008 12:23 pm

tommudd wrote:

But soon I hope to have 4.10s installed :twisted:

me too but the darn parts are soo expensive! I got a good mechanic tha said he could install the gears for me for about $550 and I can get all of the gears for a good prrice but the ones for the D30A the cheapest is $216

which isnt bad im just cheap lol

BeepBeepJeepJeep · **Posted:** Thu Jul 31, 2008 12:29 pm

JL Rockies wrote:

After installing my 4.10 gears, I just burned through my first full tank of fuel. I am happy to report that my economy increased 1.5 mpg. Any increase is OK but to put things in context; I was down 8 mpg from stock after all the weight and lift was added. Now I am rockin down the road at 20 mpg......yeah baby!

20mpg? For a CRD? Isn't that... Really bad?

tjkj2002 · **Posted:** Thu Jul 31, 2008 12:31 pm

BeepBeepJeepJeep wrote:

JL Rockies wrote:

After installing my 4.10 gears, I just burned through my first full tank of fuel. I am happy to report that my economy increased 1.5 mpg. Any increase is OK but to put things in context; I was down 8 mpg from stock after all the weight and lift was added. Now I am rockin down the road at 20 mpg......yeah baby!

20mpg? For a CRD? Isn't that... Really bad?

Not for a lifted CRD with about a 1000lbs of armor on it.

4:10 Gears

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