Jeep Wrangler Forum banner

1 - 20 of 26 Posts

·
Registered
Joined
·
60 Posts
Discussion Starter #1
picture the scene. i am running 31" tires on my 2.5l 4 banger and i live in a place that is covered with hills. i have been looking into re-gearing to 4.56 to try and get my 5th gear back.

i am a little tight on money and don't want to buy the cheapest gears out there. i am trying to save some money on the install and since i would never trust myself with this i was wondering if it was possible to only re-gear the rear axle.

i rarely go off-roading due to school, work, and no close-by trails........i know its a shame:nonono:

i am new to the automotive world and this is my first vehicle so please don't be offended or too harsh with your replys
thank you
 

·
Registered
Joined
·
830 Posts
No you must regear both axles. If you don't then your rear wheels will be spinning at a different speed then your front wheels.
 

·
Registered
Joined
·
4,885 Posts
Yeah...as above, regear both axles...going to run you around 1200 give or take
 

·
Registered
Joined
·
2,098 Posts
You can regear only one axle at a time. However, you have to remove one of the driveshafts (front if you only regear the rear) so you can't use 4wd.
 

·
Registered
Joined
·
336 Posts
Really? I thought the answer that I was going to see to his question was that he could just do the rear, but he couldn't put it in 4wd. Shows how much I know I guess. Why does the front driveshaft have to come out if he keeps it in 2wd?
 

·
Registered
Joined
·
2,098 Posts
Really? I thought the answer that I was going to see to his question was that he could just do the rear, but he couldn't put it in 4wd. Shows how much I know I guess. Why does the front driveshaft have to come out if he keeps it in 2wd?
To avoid binding in the t-case
 

·
Knows a couple things...
Joined
·
48,897 Posts
No, the front driveshaft does not need to be removed if the f/r axle ratios do not match. Absolutely not required. You couldn't use 4x4 but that's it.

And not even factory front/rear axle ratios match precisely... with the exception of the Rubicon with matching f/r axles, Jeep axle ratios are generally .01 different between the f/r. As in 4.10/4.11, 3.73/3.74, 3.54/3.55, 3.07/3.08. And even if they match precisely as the Rubicon's do, the front & rear axles still turn at different rpms since the front tires rotate faster than the rears do on turns or curves.
 

·
Knows a couple things...
Joined
·
48,897 Posts
So even in 2wd you're still "connected" to the rear axle?
Nope, at least not if I understand your question. The sporadic advice that you somehow "must" remove your front driveshaft if your axle ratios don't match is not true for a Wrangler TJ. You just need to avoid using 4x4.
 

·
Registered
Joined
·
440 Posts
As Jerry said you do not absolutely need to disconnect the front driveshaft. When the transfer case is in 2wd both the mainshaft and the front output shaft can both move independantly as the T-case drive chain is not linking them in unison.
But removing the front driveshaft can keep you from accidentally engaging 4wd and causing yourself a world of headaches.
 

·
Knows a couple things...
Joined
·
48,897 Posts
But removing the front driveshaft can keep you from accidentally engaging 4wd and causing yourself a world of headaches.
I dunno about you but I have never accidentally engaged 4x4. And if you're sitting still & engage 4x4, the most that will happen is things will start binding as you start to drive off... but it will bind up enough to stop you at a still slow speed, not break things. You'd have to try real hard like engaging 4x4 at highway speeds with good traction... you know, stupid stuff... before any damage might occur. Keep in mind that not even the factory f/r ratios are perfectly matched... and even if they were, you still can't drive in 4x4 on a high traction surface or highway without it eventually binding... it would still bind up for the reason mentioned in my earlier post. :)
 

·
Registered
Joined
·
440 Posts
I dunno about you but I have never accidentally engaged 4x4. And if you're sitting still & engage 4x4, the most that will happen is things will start binding as you start to drive off... but it will bind up enough to stop you at a still slow speed, not break things. You'd have to try real hard like engaging 4x4 at highway speeds with good traction... you know, stupid stuff... before any damage might occur. Keep in mind that not even the factory f/r ratios are perfectly matched.
I would agree with you. I have never accidentally engaged my 4wd and dont see that happening. I was more thinking on the lines of stupid stuff like you said. Someone forgetting and engaging 4wd in low/no traction situation and then carrying some speed on to solid ground. I dont know how much force it would take to start breaking stuff, but i do know people do stupid things and somehow find a way for people to say WTF.

If it was me I wouldnt remove my front driveshaft, but just wanted to point out that it is still an option.
 

·
Registered
Joined
·
336 Posts
Nope, at least not if I understand your question. The sporadic advice that you somehow "must" remove your front driveshaft if your axle ratios don't match is not true for a Wrangler TJ. You just need to avoid using 4x4.
Thanks for the clarification, Jerry. When I posted that question your First post hadn't showed up for me yet. That's how I always understood it, that you were in no way connected to the front in 2wd. Just thought I might have been missing something, as I know there are a lot of folks on here that know more than I do.
 

·
Registered
Joined
·
2,098 Posts
Sorry it was early and as I was cutting my grass I realized that what I said wasn't true and I was just getting back on to say that. But thanks for the correction Jerry!

However, if you're worried about someone else accidentally engaging it (I don't typically let other people drive my Jeep, very few have, but some people are more giving than me :D ) or if you're real forgetful, it still might be a good idea in my opinion :)
 

·
Registered
Joined
·
60 Posts
Discussion Starter #15
thank you guys so much for all of the replays.

so what i am getting from all this is that it is possible but once it is done i can't use 4hi/4low. its kinda what i guessed.

it will only be temporary until i can make enough money to re-gear the front axle.

is there anything else that i need to worry about?
 

·
Registered
Joined
·
60 Posts
Discussion Starter #17
one last question. exactly what do i need to buy for this project. ring? pinion? gear?

also what is a good website to order off of?

and finally what is a good brand?

sorry for all of the questions.

:Thanx:
 

·
Registered
Joined
·
69 Posts
I just regeared my 4 banger. It's a manual which had the 4.10s. I am running a 285 series tire(about a 32-33) and the 4.88s are not all that overgeared. What I'm saying is I would not go to the trouble of regearing unless I was going all the way to the 4.88s. If yours is a auto, it may be different. I've heard they pull better with the lower(numerical) numbers. I now can use 5th gear all the time, whereas before it was only on the interstate while running downhill.
Chris
 

·
Registered
Joined
·
60 Posts
Discussion Starter #19
mine is manual. i hear that if i were to regear it to 4.88 then i will loose my top speed but will gain acceleration i am just looking for something in-between because i don't think that i will run any tires bigger than the 31s i got on it
 

·
Knows a couple things...
Joined
·
48,897 Posts
mine is manual. i hear that if i were to regear it to 4.88 then i will loose my top speed but will gain acceleration i am just looking for something in-between because i don't think that i will run any tires bigger than the 31s i got on it
4.88 gearing for 31" tires would be excessive for sure. However, 4.88 gears would however be very appropriate for the 2.5L engine and 33" tires and would actually restore top speed lost with the factory 4.10 gearing after installing 33" tires. For your 31" tires, I wouldn't change your existing 4.10 gear ratio. :)
 
1 - 20 of 26 Posts
Top