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Discussion Starter · #1 ·
My wife just got a sweet bonus at work and told me I can order gears (and maybe a Detroit Locker) for being such a great husband. /wwwthreads_images/icons/cool.gif

I've looked at the various charts and calculators posted by Randy's and 4 Wheel Parts Wholesalers...

http://www.ringpinion.com/calc-rpm.html

http://www.4wheelparts.com/Tirel_gear_ratio.asp

...but still don't know what ratio I want.

My '86 CJ is currently running the original 258 (Weber & TR/MSD Ignition), T-5 (0.76 overdrive), Dana 300, and 3.54s in the pumpkins. My current tires are 32x11.50 Super Swamper TSL/SXs. No plans for engine/trans/transfer case changes, but maybe bigger tires (33s or 35s) in a few years.

I do some highway/interstate driving, but it is mostly to and from the trails. I'm afraid to go so high (4.56) that I can't do 65-70 mph anymore, but if I go with 4.10s and ever get bigger tires I will be right back where I started.

I know everybody who has done a gear swap has had to address this problem and would love to hear from anybody who regularly drives a 258 with 32s or 33s and 4.56 gears. Was it a mistake, or the best mod you ever made?

JEEP...It's whats for dinner.
 

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I run 33's with 4.56's, detroits, and a .73 overdrive. I run outta RPMs before I run out of power. 65 is very managable (about 2500) and 70 is more exhilerating than I need most days, so I don't push it.

If you're even thinking about larger tires, you won't regret the lower gears in the future, it'll save you from having to do it over. It's cheaper/easier to swap tires than gears.

'83 CJ-7 nothing original but the tub and axle tubes
 
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Discussion Starter · #3 ·
Thanks for the reply again bluseman.

I guess I'll go with the 4.56s unless somebody can convince me otherwise. I haven't used fifth gear since I put on the 32s and it is probably feeling neglected.

JEEP...It's whats for dinner.
 
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Discussion Starter · #4 ·
I am running 33's with 4.56 and I am cranking about 6300 on the highway at 65 and 6500 at 70 I really like them, but I am thinking about running 35's soon.

'82,CJ7,D44'S,ARB'S,BDS SUSP.,FULL CAGE,4.0 HO,NV4500,DANA300 TWINSTICK
 

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Hey, Spike, you need to calibrate that tachometer. I think you are about 2-3 times too high.

 

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I'm kinda thinking the same thing. Looks like with 33's and 4.56s I will be in the 3000rpm range.

 

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I also have 33's w/4.56's & TH-700R4 w/o.d. When going down the freeway it's useless putting it in 4th, (o.d.), unless going 60 or above due to low rpms. I believe the stock setup on cars w/o.d. would be to shift into o.d. between 45-50 mph. I am presently thinking of switching to 5.38's which should allow for 75 mph in o.d. w/o too many rpm's. I would seriously advise anyone with an o.d. tranny to go with 4.88's or lower for better low-end and crawl and retain the functionality of the o.d. without lugging the engine.

Tim
'66 Jeepster Commando w/Buick 252/4.1L V-6
'70 Wagoneer w/Buick 350 V-8
'76 Wagoneer w/AMC 401 V-8 (sold)
 
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Discussion Starter · #8 ·
I have them on my yj with 33's, and would not trade them for the world.. I love them.. I do run out of gear though.. but I don't like the jeep over 70 anyways

4in currie lift, 4.56's, true trac, and 33's.. yeah it's a start!
 
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Discussion Starter · #9 ·
I just put on a set of 4.56 gears on my 91 jeep wrangler last week...and I don't know why I waited so long to get them!! I'm currently riding on 32" tires, but I do plan to go bigger, maybe 33's or 35's. Before the swap, I didn't even know if 5th gear even worked, because I never used it. I couldn't drive up an ant hill without downshifting to 3rd. But that's all changed now. Best thing I ever did to it....

 
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Discussion Starter · #10 ·
Thanks for all the responses. Nobody seems to think that a 4.56 ratio is to low for 32" tires so...

The new Superior Axle & Gear 4.56s are in the garage. Quadratec sent me a wrong install kit though. Why would you ship a Chrysler 8.25 install kit with AMC 20 Gears? The killer is the "Packed with Pride by #74" sticker on my invoice.

and

The Detroit for my AMC 20 rear is on it's way from 4-Wheel Parts Wholesalers ($508.95, Free Shipping-but $5 handling, and a free copy of the 1999 TTC Video).

Since I have to change the carrier in the Dana 30 front end (Currently have factory 3.54 gears) I was thinking about the Detroit Tru-Trac. I know it is not "real" locker but I'd like to maintain some highway manners in 4-high. Any thoughts?


JEEP...It's whats for dinner.
 
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Discussion Starter · #11 ·
4.56 w/ 258, 33s & T5 should be perfect. Just to "nit-pick" I'm pretty sure the T5 5th gear is 0.80:1.

'80 CJ7 w/ AMC401, T18a, TeraLo Dana 20, soon to be sprung over w/ dual Dan 60s!!
 
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Discussion Starter · #12 ·
I'll chime in, I think 4.56's are great with 33's, and with an OD tranny would not hesitate to run it with 32's. I have been pleased with my 33 4.56 combo. My next change will be the Tera-low kit in the t-case. I think you have made a good choice.

Cage Up, Wheels Down
Jeepfiend
All my Jeeps are in pieces! Except for one!!
 
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Discussion Starter · #13 ·
I had a 86 CJ7 with 258, T-5, D300 and install 4.56 gears.

I loved it, ran many sizes from 31's to my preferred 36's.

The 31's were too small for highway and found 33's worked great.

Later,

76 CJ5 304 "its a JEEP thing, I hope you understand"
 

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I run the Detroit in mine (front and rear). I think they get a bad rap. Once you've gotten used to driving with them they are very manageable. They get a bit squirrelly in snow/slick, but what doesn't?

One other thought I neglected to mention before. With those lower gears and locker you will be able to apply a LOT more low end torque to your 20 without even trying. I spun the tubes on mine at a stately 1200RPM. I would also strongly recommend either a truss, and/or welding the tubes.

Take a look at http://www.mo-offroad.com/ for a good truss solution on the 20.

'83 CJ-7 nothing original but the tub and axle tubes
 

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I'm another satisfied customer of 4.56's 33 inch tires and t5 tranny. I run at about 2500 rpm's at low 60 somthing mph.

Tim

84 CJ7, 258, HEI, M/C 2100 carb, 5 inch lift, RS9000's, 33x12.5 BFG M/T's, 4.56's and Detroit softlocker, full cage & belts, Xenon flares, Dana 44 rear, GM dual diaphragm brake booster
 
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Discussion Starter · #16 ·
I was planning on installing a Powertrax in my rear d35 so I wouldn't have to mess with backlash, preloads, etc. I'm not sure if the Truetrac requires that or not. By the way, after putting in 4.56 gears, my speedo must be really off, because it shows me doing 75 MPH, and it only feels like 55! I suppose that requires changing that little gear-thingy in the transmission that runs to the speedo...

 

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Truetrac replaces the stock carrier as well, so you need to set up the gears again. Only the lockright, ez locker and quick lock install inside the existing carrier.

See your Chrysler dealor for the speedo gear.

84 CJ7, 258, HEI, M/C 2100 carb, 5 inch lift, RS9000's, 33x12.5 BFG M/T's, 4.56's and Detroit softlocker, full cage & belts, Xenon flares, Dana 44 rear, GM dual diaphragm brake booster
 
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