Help Me 4:88 or 5:13 gears !

harbe692004

harbe692004

New Member
Joined
Oct 20, 2009
Location
Morganton
i've got a 08 4 door JK auto and 3:73 with 35's. And right now it wouldnt pull a greasy string out of a cats a$$ ! Most everbody on jkforum says to go with 5:13 gears with 35's there was one that said his 5:13 seemed to be to much gear for the road. The chart on the for rpms at 70mph with 5:13 was like 2380 it tacs about 1700 right now with stock 3:73 and wont hold OD. Need help ! Does anybody have some insite on this that could help ?
 
do you plan on going bigger? if not 4.88s should do fine and still give a good all around rpm. if you plan on going to 37s then then i would step up with the 5.13s. my xj has 4.88s with 37s and i wish i would have went 5.13s
 
harbe692004 said:
i've got a 08 4 door JK auto and 3:73 with 35's. And right now it wouldnt pull a greasy string out of a cats a$$ ! Most everbody on jkforum says to go with 5:13 gears with 35's there was one that said his 5:13 seemed to be to much gear for the road. The chart on the for rpms at 70mph with 5:13 was like 2380 it tacs about 1700 right now with stock 3:73 and wont hold OD. Need help ! Does anybody have some insite on this that could help ?
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go with 5:13's and an auto. I've had them with 35's on my JKU for the last 67K miles and no way would I be happy with 4.88's. If you want we could meet up and you can take mine for a drive. BTW jkf sucks, eddie is douche bag, come over to jkowners :beer:

The JK's 3.8 NEEDS the 5.13's to get it where the power is at, what little there is :lol: I can still cruise 70-80mph at about 2500-2700 rpm. If you ever went to 37's you'll wish you had 5.38's and I know a few that have 5.38's with 35's and are happy.
 
tkob1060 said:
go with 5:13's and an auto. I've had them with 35's on my JKU for the last 67K miles and no way would I be happy with 4.88's. If you want we could meet up and you can take mine for a drive. BTW jkf sucks, eddie is douche bag, come over to jkowners :beer:

The JK's 3.8 NEEDS the 5.13's to get it where the power is at, what little there is :lol: I can still cruise 70-80mph at about 2500-2700 rpm. If you ever went to 37's you'll wish you had 5.38's and I know a few that have 5.38's with 35's and are happy.
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is urs a dd ? what kinda wheelin do u do ? what kind of mpg do u get now ?
 
I have A bronco 38's with 4.56 gears and would be unhappy with 5.13. It's hard for me to imagine 5:13 with 35's.

I have another bronco with 36's and 4.10 gears and it works very well.

Since you have a small motor you may need to compensate some, but 4.56 should be plenty. If you go with 5.13 the motor will be at high RPMs at highway speeds and gas mileage will go way down.
 
GubNi said:
I have A bronco 38's with 4.56 gears and would be unhappy with 5.13. It's hard for me to imagine 5:13 with 35's.
I have another bronco with 36's and 4.10 gears and it works very well.
Since you have a small motor you may need to compensate some, but 4.56 should be plenty. If you go with 5.13 the motor will be at high RPMs at highway speeds and gas mileage will go way down.
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This is the way I looked at it also,

But skiming through the JK forum, Everyone states your crazy not to do 513s on 35s, Stating they have do theres and it works great.
 
GubNi said:
I have A bronco 38's with 4.56 gears and would be unhappy with 5.13. It's hard for me to imagine 5:13 with 35's.
I have another bronco with 36's and 4.10 gears and it works very well.
Since you have a small motor you may need to compensate some, but 4.56 should be plenty. If you go with 5.13 the motor will be at high RPMs at highway speeds and gas mileage will go way down.
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This is the way I looked at it also,

But skiming through the JK forum, Everyone states your crazy not to do 513s on 35s, Stating they have do theres and it works great.
 
If it were more of a wheeling rig living with 2700 rpm cruising down the interstate is no problem, but not as much of a dd as it is. Shit would get old quick.
 
GubNi said:
I have A bronco 38's with 4.56 gears and would be unhappy with 5.13. It's hard for me to imagine 5:13 with 35's.
I have another bronco with 36's and 4.10 gears and it works very well.
Since you have a small motor you may need to compensate some, but 4.56 should be plenty. If you go with 5.13 the motor will be at high RPMs at highway speeds and gas mileage will go way down.
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Either of those Broncos have a small V6 under the hood with an OD transmission? Our old Exploder had 4.10s and 28" rubber. Worked just fine.

What's the OD gear on that Jeep? .68ish? I'd say the deeper diff gears, the better. Maybe check and see how the 5.13 and 5.38 gearsets hold up in those axles, but I think that's where you should be looking, especially so if you have any plans of going to larger tires.
 
I would go with the 5.13's if you are going to wheel it. If you are going to just drive it on the road I would say 4.88's would work. I think you will be happy either way getting away from the 3.73's. I am planning on going to 5.38's in the next month or so with mine. Mine is a 6 spd though and I run 37's. I have 4.10's now and I drive it daily it just sucks when you start to hit the hills.

Jeremey
 
You should run 5.13s if you have the auto....if you had the 6 spd you could run the 4.88s. I'm on the JK boards quite a bit and have some good experience with them....go 5.13
 
With the auto I'd go 5.13s. I'm running 4.88s on my XJ with 34s and I have no complaints on the trail or off however I think the 5.13s would do a lot better on the trail and still provide me with plenty of top speed on the road since I'm running an auto.
 
Apples and oranges.
I have a TJ with auto and 4.88's on 37's. The I6 has more get up and go than the V6 and it still will not get out of it's own way and I don't have over drive either. My best possible hwy speed is 55mph down hill with a tail wind.

I have a I6 ZJ with 4.56 on 33's auto w/OD. Cruises around town just fine but will not hold OD on the hwy very well.

An auto sucks the life out of your power plant and with OD it's even worse. In both my Jeeps I wish I had gone a little lower on the gearing, as in 5.13 on the TJ and 4.88 on the ZJ. but what's done is done. Running a higher RPM on the hwy is more tolerable than always downshifting to keep speed, IMHO.
 
I am not familiar with the axles under the JK, if it is still the d30/d35 combo, wouldn't 5.13 in the 30 mean only one tooth would be engaged at a time in the gears? Would this lead to problems? 5.13 just seems like some big teeth in a small d30
 
BigClay said:
I am not familiar with the axles under the JK, if it is still the d30/d35 combo, wouldn't 5.13 in the 30 mean only one tooth would be engaged at a time in the gears? Would this lead to problems? 5.13 just seems like some big teeth in a small d30
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The D30s on the JKs are not the same as a TJ, They can go to 5.13 as apposed to 4.88 in a TJ, But yeah that is a small pinion head.
 
harbe692004 said:
is urs a dd ? what kinda wheelin do u do ? what kind of mpg do u get now ?
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yes its my DD, I wheel rocks and mud, more mud then rocks till I moved to NC. umm MPG? Its a Jeep :lol:

I believe 5.13's scare people so much because they think of old muscle cars and you would have Zero top end with 5.13's lol BUT it is a jeep running much bigger tires. I have ZERO problems running highway speeds like I said of 70-80, I can easily get to 90mph. The engine at 2500-2700rpm is not screaming, that is where its making power, it NEEDS To be there, specially to hold overdrive so the trans is not constantly down shifting trying to stay at speed.

saf-t scissors said:
Either of those Broncos have a small V6 under the hood with an OD transmission? Our old Exploder had 4.10s and 28" rubber. Worked just fine.
What's the OD gear on that Jeep? .68ish? I'd say the deeper diff gears, the better. Maybe check and see how the 5.13 and 5.38 gearsets hold up in those axles, but I think that's where you should be looking, especially so if you have any plans of going to larger tires.
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the OD gear is .68 or .67 I forget. From what I've seen the 5.13's have been holding up great, and not to many running the 5.38s but have yet to see anyone say they broke them.

ABadJeeper said:
If you are going to just drive it on the road I would say 4.88's would work. I think you will be happy either way getting away from the 3.73's. I am planning on going to 5.38's in the next month or so with mine. Mine is a 6 spd though and I run 37's. I have 4.10's now and I drive it daily it just sucks when you start to hit the hills.
Jeremey
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you tell him 4.88's would work but yet you plan on going to 5.38's with a 6spd which doesnt need to have as low gearing. Will 4.88's be better then his 3.73's YES. Will it be enough to hold the trans from not downshifting when he hits the hills, not likely, some yeah but the 5.13's will be better and without a real negative.

CarolinaTruggies said:
Wait til Eddie finds out who I am on there.
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Well Alex the build is almost done so when you spilling the beans :lol:

I know everyone is trying to compare their vehicle and gearing choices to the JK but none of you have the wonderful minivan engine :lol:

OP what is your big concern with going to 5.13's? Everywhere you look JKF, JKO and JF everyone says do 5.13's with 35;s and auto. Have you found anyone that said they were unhappy with them? I've never seen it. Anyone ever complain they cant drive on highway with them? Nope never seen it.

here is a dyno run graph posted by rippmods on jko, notice the rpm's on bottom 2500+ the motor doesnt make crap for power below that
awww.rippmods.com_v_vspfiles_photos_072010JK38_LTHDR_4.jpg


The offer still stands if you want to take my jeep for a drive. I'm going to Jeep Beach tonight though, so it will have to be sometime next week/weekend.
 
Thanks alot guys yall have been a great help in figurin this out and i know now that 5.13s are the place to be ! Cheers up to tkob1060 you've been a big help if i get a chance to take u up on ur offer i'll have to buy u a :beer: Now who knows who can get them and put them in for a good price ?
 
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