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post #1 of (permalink) Old 10-17-2000, 07:14 AM
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TJ Needs Gears! Opinions?

Guys,

Over the weekend (Read the post "The club trip that wouldn't end" for info.

I broke all of the bolts holding the ring gear onto the carrier. We were able to get all of the broken bolts out but the pinion has a chip in the gear. So I am going to order new rear gears today.

I assume it has 4:11s cause its a 4cyl,stick right? I currently have 33" Thornbirds and I don't have 5th gear. Will 4:56's do the trick? I realize i will have to do the front but I am in the middle of putting a new drivetrain in my cj so money is low. I plan on puling the front drive shaft for a couple of weeks on the TJ.

Will the 4:56's do the trick? Can I go lower? Thanks~



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post #2 of (permalink) Old 10-17-2000, 07:54 AM
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Re: TJ Needs Gears! Opinions?

To be able to use the 5th gear, with your 4 cylinder, I'd look into 4.88 gears. How much do you drive it on the highway?

Going to http://www.off-road.com/jeep/tech/trans/ax5.html to find out what the AX-5 has for an overdrive, then to http://www.ring-pinion.com/RPMCalculator.html to figure out the RPM's, the OD and 4.88's will put you at an overall final ratio of 4.15, which at 65 mph translates to 2,750 rpm's, right in the middle of the range for 4 cylinders (2,200-3,200 RPM's). Any lower gears than that and you'd also really start to decrease the strength of the ring and pinion. Check to make sure they're made first, you may have to go to 4.56 or 5.13's, but 4.88's would be the best ratio in my book.

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post #3 of (permalink) Old 10-17-2000, 08:02 AM
 
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Re: TJ Needs Gears! Opinions?

Actually, 4.88 gears are the lowest they make for the Dana 35c, and those aren't factory gears either. The lowest Spicer made was 4.56 so an aftermarket vendor (Superior?) came up with the 4.88s. I know Randy's R&P sells them, so he would be the first person to call.

Restoring a '74 DJ-5C [img]/wwwthreads_images/icons/cool.gif[/img] It was running good, so I messed with the carb to make it run better. Now it wont run at all! [img]/wwwthreads_images/icons/mad.gif[/img]
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post #4 of (permalink) Old 10-17-2000, 08:10 AM
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Re: TJ Needs Gears! Opinions?

Somebody told me that 4:56s is the only option unless I change the carrier.. not sure. I don't normally take it off road since I have my CJ now. I drive it daily to work and stuff.





1997 TJ w/ 33's
1984 CJ7 V8 SOA w/35's or 39's
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post #5 of (permalink) Old 10-17-2000, 08:45 AM
 
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Re: TJ Needs Gears! Opinions?

Read my previous post and then call Randy (check out his website too)

Restoring a '74 DJ-5C [img]/wwwthreads_images/icons/cool.gif[/img] It was running good, so I messed with the carb to make it run better. Now it wont run at all! [img]/wwwthreads_images/icons/mad.gif[/img]
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post #6 of (permalink) Old 10-17-2000, 02:26 PM
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Re: TJ Needs Gears! Opinions?

A 4 cyl is marginal at best in STOCK condition on the freeway. Yes, it will go 70 mph, but it should really be considered a 60 mph veh. Small hills or a head wind will stop you from doing 70 mph.

When you change to heavier tires, you need MORE power to maintain the same speeds as you did with lighter tires. Your gearing does need to be changed accomodate taller tires. 4.56s will help 4.88s will give you more rpms and a bit more power, but you will NOT get back to abilities your 4 cyl had on the hwy with stock tires. The 4 just doesn't have any spare power for those heavier tires. The extra foot print of the wider tires takes a little more power too.

IMO the 4 cyl is a great off road veh. It is lighter, more fuel efficient and there is more room under the hood to mount stuff. It can be geared to do anything the large cube engines can do EXCEPT sling mud at high wheel rpms. On the hwy the 4 gets along quite nicely at 55/60 mph, and you can do that with heavy tires too, but to consider it an all around 70 mph freeway veh is really pushing it.

I haven't heard this mentioned, but it seems to me like the the 4 cyl TJ would really benefit from front locking hubs. The TJ front axle turns all the time. That takes some power. If you unlocked the hubs so that just the wheels turned, seems to me like it would help.



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post #7 of (permalink) Old 10-17-2000, 04:44 PM
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Re: TJ Needs Gears! Opinions?

my opinion...
you'll be changing axles so often in that dana 35 with 4.88 gears... i really believe that it is the weakest axle ever put into a jeep, and the added stress of the gear reduction will shred components. if you tore off the ring gear before, what will stop you from doing it again when you have more torque available?
or, since you allready have the cj to beat, just pop some new gears into the 35....and go with the 4.88's

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post #8 of (permalink) Old 10-17-2000, 05:02 PM
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Re: TJ Needs Gears! Opinions?

Maybe we should just put the suburban on a diet and maybe it wouldnt have hurt so much. Damn i still am tired from sunday.

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post #9 of (permalink) Old 10-17-2000, 08:14 PM
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Re: TJ Needs Gears! Opinions?

Maybe we should just pitch in some money and get the burban a WINCH that will pull it out! I am still tired also!


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post #10 of (permalink) Old 10-18-2000, 06:29 AM
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Re: TJ Needs Gears! Opinions?

I ordered some 4:88's for the rear. I will hopefully have this installed before Monday. Once my CJ is back on the road I will save some money for the front rear in the TJ.

Thanks



1997 TJ w/ 33's
1984 CJ7 V8 SOA w/35's or 39's
http://members.aol.com/a4x4jeeper/
www.jeepeast.com/overmost
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