4.10 gearing........is it worth it ...pros and cons?

Robert Bradbury · **Joined:** Wed Mar 22, 2006 10:37 am **Posts:** 132

Morning all!!!

O.K. so I already have the 4.10 brand new in the box. I have the jeep lifted, the 32 inch tires, all the armor and bumpers
with the winch....bla bla bla.

My transmission guy has been putting off putting in the 4.10 saying I WILL NOT LIKE IT. That I will burn MORE gas and on the highway will be annoying with the higher revs.

What should I do, install it or stay away ? I bought it to regain torque that I had lost and for better gas milage that some say
was the case.

Robert

Fulltimer · **Posted:** Wed May 07, 2008 6:59 am

My understanding, from reading posts on here, is that as long as you keep your speed down below 65 you WILL regain MPG and the power you lost with the bigger tires. I'm sure that some of the guys on here that have gone to the 4.10's and bigger tires will come on with their results.

I just went to 31.7" tires and took a pretty good hit on MPG. My plans are to get 4.10's.

Terry

tjkj2002 · **Posted:** Wed May 07, 2008 7:52 am

Robert Bradbury wrote:

Morning all!!!

O.K. so I already have the 4.10 brand new in the box. I have the jeep lifted, the 32 inch tires, all the armor and bumpers
with the winch....bla bla bla.

My transmission guy has been putting off putting in the 4.10 saying I WILL NOT LIKE IT. That I will burn MORE gas and on the highway will be annoying with the higher revs.

What should I do, install it or stay away ? I bought it to regain torque that I had lost and for better gas milage that some say
was the case.

Robert

Time to find another installer,with all that weight and those taller tires the lower the gears the better to gain back mpg's and power.I gained mpg's with the 4.10's over the 3.73's,on the highway(last trip) I was getting a average of 19mpg's at 75mph,real good for a 55oolbs brick.Though 4.56's would be better for both mpg's and power with 32" tires and all that weight.

tommudd · **Posted:** Wed May 07, 2008 9:27 am

If you would of stayed at say a 29 or 30 inch tire and went to 4.10s I could see where someone would say going to 4.10s would hurt your mileage , but with the larger tires and the extra weight as Troy stated you need to go to 4.10s at least ( well also thats all we have available) Its a common mispreception when you talk about lower gears.

go for it! :wink:

Tom

bugnout · **Posted:** Wed May 07, 2008 10:11 am

I haven't seen a drop in MPG, I think its better especially at 60-65. I'm only running 31"s and aluminum wheels. Changing to 4:10's made my speedo more accurate with these tires.

I put 4:10's in at the same time I installed lockers. Not sure what the expense would be just to put the gears in. if its a lot, maybe you need a better reason to install them.

Robert Bradbury · **Joined:** Wed Mar 22, 2006 10:37 am **Posts:** 132

bugnout wrote:

I haven't seen a drop in MPG, I think its better especially at 60-65. I'm only running 31"s and aluminum wheels. Changing to 4:10's made my speedo more accurate with these tires.

I put 4:10's in at the same time I installed lockers. Not sure what the expense would be just to put the gears in. if its a lot, maybe you need a better reason to install them.

I had the mechanical locker in but removed it because it broke . I have it fixed but I'm on the fence
about what to do now. I would like to be able to lock and unlock so I guess the air locker would be best.
What did you install??

I wish I had the CRD, my six eats gas. Any pictures to forward??

Robert

tommudd · **Posted:** Wed May 07, 2008 12:11 pm

Robert Bradbury wrote:

bugnout wrote:

I haven't seen a drop in MPG, I think its better especially at 60-65. I'm only running 31"s and aluminum wheels. Changing to 4:10's made my speedo more accurate with these tires.

I put 4:10's in at the same time I installed lockers. Not sure what the expense would be just to put the gears in. if its a lot, maybe you need a better reason to install them.

I had the mechanical locker in but removed it because it broke . I have it fixed but I'm on the fence
about what to do now. I would like to be able to lock and unlock so I guess the air locker would be best.
What did you install??

I wish I had the CRD, my six eats gas. Any pictures to forward??

Robert

Robert
just give up and get rid of the 4.10s send them to me and I will dispose of them for you! :twisted:

Tom

bugnout · **Posted:** Wed May 07, 2008 12:28 pm

Robert Bradbury wrote:

bugnout wrote:

I haven't seen a drop in MPG, I think its better especially at 60-65. I'm only running 31"s and aluminum wheels. Changing to 4:10's made my speedo more accurate with these tires.

I put 4:10's in at the same time I installed lockers. Not sure what the expense would be just to put the gears in. if its a lot, maybe you need a better reason to install them.

I had the mechanical locker in but removed it because it broke . I have it fixed but I'm on the fence
about what to do now. I would like to be able to lock and unlock so I guess the air locker would be best.
What did you install??

I wish I had the CRD, my six eats gas. Any pictures to forward??

Robert

ARB's front and back. What kind of pictures?

Here is my KJ at Moab this spring
http://www.lostjeeps.com/forum/phpBB3/viewtopic.php?t=31584

tommudd · **Posted:** Wed May 07, 2008 12:36 pm

bugnout
hows the steering feel after you got the ARBs installed? Any major difference in the way it handles or drives on and off road?

Thanks

Black_Dog · **Posted:** Wed May 07, 2008 4:09 pm

I have the 4.10 rear end with stock 29” tires (the optional SR-A’s, not the ST’s). Over 44K miles I have averaged better than 16 mpg. On the highway with roof rack and loaded with gear I average 18.6 mpg and in town I get 15.5 mpg. I don’t think these numbers are too different from the guys running around with the 3.73s, skinnier tires and no skid plates.

And there are no annoying high revs at freeway speeds. I cruise at 75 mph at a quiet (except for wind noise) 2,300 rpm. You can subtract from that due to your larger tires. By comparison, at the same speed in my I4 Honda Accord I’m turning 2,950 rpm.

One possible negative consequence: my rear wheel traction is especially loose in 4x2 on wet roads. My wife now refuses to drive the thing in the rain and I find myself engaging Part-Time 4WD more often than is probably good for the KJ on surface roads. I know this has much to do with the crappy SR-A’s. But I think having the larger gear ratio might make it a little harder to modulate traction on slick roads.

tommudd · **Posted:** Wed May 07, 2008 5:05 pm

I think 98% of the problems with wet roads will be directly connected with the tires, I used to be able to burn rubber like crazy all the time, then switched out the tires and all the fun was gone! But it was really bad on wet roads

InCommando · **Posted:** Wed May 07, 2008 6:37 pm

Go to one of the numerous gear claculators, punch in your new figures, and I think you will find that the 4.10's will just be returning you to close to stock. Stock is probably an engineering compromise bewtween acceptable performance and acceptable MPG.

bugnout · **Posted:** Wed May 07, 2008 8:00 pm

tommudd wrote:

bugnout
hows the steering feel after you got the ARBs installed? Any major difference in the way it handles or drives on and off road?

Thanks

No issues with steering, don't even notice the front locker until its engaged. I do notice the trak-loc is gone. I had gotten use to the added traction all the time. Now I have to remember to engage the rear locker if I want to beat the guy next to me when the light turns green

After seeing a couple of front diffs grenade on basically minor obstacles, I feel a lot more secure with the locker up front. I feel that having both wheels turning will go a long way to prevent that from happening. :evil:

Traction off road is tremendously better. I was able to do some obstacles I wouldn't have thought possible. I was out there with some guys who aren't satisfied unless they almost roll their rigs, and will seek out the hardest line every chance they get. They talked me into trying a lot of stuff I wouldn't normally do.

Next issue is to get it higher and improve the breakover. Can't remember which magazine recently ran an article titled "Articulation vs Traction". With the ARB's I can attest, traction beats out articulation every day.

tjkj2002 · **Posted:** Wed May 07, 2008 8:46 pm

bugnout wrote:

tommudd wrote:

bugnout
hows the steering feel after you got the ARBs installed? Any major difference in the way it handles or drives on and off road?

Thanks

No issues with steering, don't even notice the front locker until its engaged. I do notice the trak-loc is gone. I had gotten use to the added traction all the time. Now I have to remember to engage the rear locker if I want to beat the guy next to me when the light turns green

After seeing a couple of front diffs grenade on basically minor obstacles, I feel a lot more secure with the locker up front. I feel that having both wheels turning will go a long way to prevent that from happening. :evil:

Traction off road is tremendously better. I was able to do some obstacles I wouldn't have thought possible. I was out there with some guys who aren't satisfied unless they almost roll their rigs, and will seek out the hardest line every chance they get. They talked me into trying a lot of stuff I wouldn't normally do.

Next issue is to get it higher and improve the breakover. Can't remember which magazine recently ran an article titled "Articulation vs Traction". With the ARB's I can attest, traction beats out articulation every day.

It sure does!!!!!!!!!

I would have went with the front ARB but I liked the idea of my TT always working while in 4wd and still be able to turn.You can tell it's there in 4wd but turning is not really any harder since the TT will "unlock" when turning and does not decrease turning radius at all.I can crawl up places that open KL's just can't go with the lack of articulation.Plus that TT up front is totally awesome on ice/snow when in 4wd,pulls you where ever you turn the wheel,very nice

!

tommudd · **Posted:** Wed May 07, 2008 9:06 pm

Glad to hear about what you said tjkj about the snow, thats one of the things I was wondering about was the reaction in snow, settles it a little bit more for me TT is still on the top of my list for the front!

bugnout · **Posted:** Wed May 07, 2008 9:56 pm

tommudd wrote:

Glad to hear about what you said tjkj about the snow, thats one of the things I was wondering about was the reaction in snow, settles it a little bit more for me TT is still on the top of my list for the front!

I might have gone with a TT upfront, but I like selec-trac, was worried about road manners in full-time 4wd.

tjkj2002 · **Posted:** Wed May 07, 2008 9:58 pm

bugnout wrote:

tommudd wrote:

Glad to hear about what you said tjkj about the snow, thats one of the things I was wondering about was the reaction in snow, settles it a little bit more for me TT is still on the top of my list for the front!

I might have gone with a TT upfront, but I like selec-trac, was worried about road manners in full-time 4wd.

Yeah having the select-trac can be a handfull with the TT up front in full time,you feel it alot more but the onroad manners are still very good just a little heavier steering.

Robert Bradbury · **Joined:** Wed Mar 22, 2006 10:37 am **Posts:** 132

How much are the ARB's and are they worth it ?
I have decided to install the 4.10 gears but am trying to decide
if I should go ARB front and rear as well . Does the ARB require
air to lock up or is it electrical?

ARB's front and back. What kind of pictures?

Here is my KJ at Moab this spring
http://www.lostjeeps.com/forum/phpBB3/viewtopic.php?t=31584[/quote]

tjkj2002 · **Posted:** Thu May 08, 2008 7:58 am

Robert Bradbury wrote:

How much are the ARB's and are they worth it ?
I have decided to install the 4.10 gears but am trying to decide
if I should go ARB front and rear as well . Does the ARB require
air to lock up or is it electrical?

ARB's front and back. What kind of pictures?

Here is my KJ at Moab this spring
http://www.lostjeeps.com/forum/phpBB3/viewtopic.php?t=31584

[/quote]The ARB's are about $750 per diff,and yes they are air operated so you will need a compressor,about another $150-$250 depending on which compressor you go with.Install is a little more pricy to install the ARB's since they have to drill/tap the axles for the air line.

Robert Bradbury · **Joined:** Wed Mar 22, 2006 10:37 am **Posts:** 132

tjkj2002 wrote:

Robert Bradbury wrote:

How much are the ARB's and are they worth it ?
I have decided to install the 4.10 gears but am trying to decide
if I should go ARB front and rear as well . Does the ARB require
air to lock up or is it electrical?

ARB's front and back. What kind of pictures?

Here is my KJ at Moab this spring
http://www.lostjeeps.com/forum/phpBB3/viewtopic.php?t=31584

The ARB's are about $750 per diff,and yes they are air operated so you will need a compressor,about another $150-$250 depending on which compressor you go with.Install is a little more pricy to install the ARB's since they have to drill/tap the axles for the air line.[/quote]

Sounds like a $ 2000 dollar job. Will have to leave that one for next year. I have to get my car restoration finished and
the airplane done first .

4.10 gearing........is it worth it ...pros and cons?

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