Topic: Re-gear prices

[stan98tj]

one of the shops im talking to is tryin to talk me into 4.10 over 4.56 because they figure if i go with 4.56, when i downshift i will spool up well farther than 3k (maybe into 3500-3700 ) and that would be screaming to stay at speed (going up a hill etc). they are afraid it will harm the motor.

[Jeffy]

one of the shops im talking to is tryin to talk me into 4.10 over 4.56 because they figure if i go with 4.56, when i downshift i will spool up well farther than 3k (maybe into 3500-3700 ) and that would be screaming to stay at speed (going up a hill etc). they are afraid it will harm the motor.

I've crawled up I-5's Grapevine which is a really steep climb doing 4000 RPM for about 15-20 minutes before.  It gets loud and angry.  What you want to do is to plug in all of your ratios into the Java calculator on jeeptech.com.  It's at the bottom.  Gearing & Tires or something like that.  It will give you all of the Speeds/RPM's for all of your gears plotted out on a graph.  Then use that to decide.

If I know there is a hill, I'll speed up in 4th (1:1, your 3rd) to get the RPM's higher up so when I hit the hill, and the RPM's drop, I will have enough to not have to downshift.  Otherwise it kinda sucks having to shift into 3rd and rev it up and hold it there.

[dwtaylorpdx]

Totally anecdotal from me but here goes....

My YJ has 220K miles on it, at 150K I had a race engine mechanic rebuild it.

After 150K miles of shifting at redline, and often way past redline,
The only really worn parts were the rings, main and rod bearings. Bores valves pistons looked great.

I really drive hard I regularly tow a small trailer and pull long passes at 3500 to 4200 rpm.

I have run Synthetic oil most of the jeeps life...

I usually run 87 octane gas. Unless its over 75 degrees out then I jump to premium.

I have had 4.56 gears since about 12K miles.

My rule of thumb is you cruise at about 60% of the redline of the engine and your fine.

I wish I had done 4.88 becasue 5th is still a little marginal on the high way on 33" tires,
I recently down stepped to 32's and it runs great and gets a bit better mileage.

Thats my twist on it...

Dave

[drunkencityworker]

If u plan arb or ox locker do it now and save. They replace the carrier and you get chargged for a second regear to be set up right. A lokrite or aussie can be added in a driveway fairly easily

[sharpxmen]

one of the shops im talking to is tryin to talk me into 4.10 over 4.56 because they figure if i go with 4.56, when i downshift i will spool up well farther than 3k (maybe into 3500-3700 ) and that would be screaming to stay at speed (going up a hill etc). they are afraid it will harm the motor.

if you have a manual transmission you should go with 4.88 if you have 33' tires. dunno with an automatic (can't remember what you have).

EDIT: nevermind, you have an auto transmission, just re-read your first post so disregard this

[Jeffy]

I have 4.88 and 33' tires set up which goes well for me...

With an automatic?

[stan98tj]

im going to be skipping out on the locker this time around. When i do go ahead and lock it will be between a true track and an e-locker.

[Jeffy]

im going to be skipping out on the locker this time around. When i do go ahead and lock it will be between a true track and an e-locker.

Just be aware a Tru-Trac isn't a locker.

[stan98tj]

Just be aware a Tru-Trac isn't a locker.

im aware. but ive read a bunch of reviews and people seem really happy with it.

[Jeffy]

im aware. but ive read a bunch of reviews and people seem really happy with it.

It depends on what you want.  If you need locker then you should get lockers.

I run a Tru-Trac/Detroit combo.

[dwtaylorpdx]

Make sure you torque the third member bolts annually or better. I blew one totally when the bolts came out....

Dave

[stan98tj]

Make sure you torque the third member bolts annually or better. I blew one totally when the bolts came out....

Dave

what do you mean?

[stan98tj]

I've crawled up I-5's Grapevine which is a really steep climb doing 4000 RPM for about 15-20 minutes before.  It gets loud and angry.  What you want to do is to plug in all of your ratios into the Java calculator on jeeptech.com.  It's at the bottom.  Gearing & Tires or something like that.  It will give you all of the Speeds/RPM's for all of your gears plotted out on a graph.  Then use that to decide.

If I know there is a hill, I'll speed up in 4th (1:1, your 3rd) to get the RPM's higher up so when I hit the hill, and the RPM's drop, I will have enough to not have to downshift.  Otherwise it kinda sucks having to shift into 3rd and rev it up and hold it there.

4k for 15-20min? i cant imagine the noise. mine screams at a hair over 3k. Basically i dont want to have to be at 3k or over for the entire highway ride. The calculators say ill be at around 3k at 65. i usually drive 60-65. 4.10s arent as good as 4.56 but the shops around here that are tryin to convince me that way are telling me that 4.10s are better highway gears than 4.56 for a 3spd auto. They say the 4.10s will be better than the stock gears both highway and offroad. My jeep has lost power but ive adapted to it. the highway ride isnt too bad. im still leaning towards 4.56 but the 4.10 guys put up a good argument. Id hate to gear to 4.56 and find myself sucking fuel down like crazy and screamin at 3k or over for the entire highway ride and then have to gear to 4.10. Of course id hate gearing to 4.10 and not having enough power to shift to 3rd and be stuck in 2nd most of the time.  Then again with 3.73 i have the power to shift through all thgears....

[Jeffy]

You're also forgetting that not having low enough gears sucks down mileage as well.  The engine is designed to run in a certain RPM range.  3000 RPM is not that high.  The powerband should start around 2700RPM and go to 3600 RPM  If you run too close to the low end you'll quickly fall out of the power band if you hit any hill.  I think, you'll have to come to the conclusion you will need to be at 3K @ 65MPH.  That's pretty normal for a non-OD vehicle.  Otherwise go to 31's or try some 33x10.5's.

I'm sure I've said this before but you can probably buy a 4.10/4.11 - 30/35 combo from a 2.5L manual for $600 or so.  If you sold your axles you could be in it for maybe $300. or keep them for spares.  You could also try to hunt down a 2004 TJ 2.4L with 4.56's stock, but they are really rare.  Still probably less then $1000.