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Unread 01-20-2010, 09:16 AM   #1
greeninwyo
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1998 TJ Wrangler 
 
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Want some input on gearing

Hey guys,
I just got all my wire problems in the dash fixed and blinkers working and all new brake parts coming the end of the week. So after that its gear time. It is a 75 CJ5 with 30 front and 44 rear with 3.73, 3 speed, 304, 33" tires and stock transfer. Last year in low, low was way to fast on the mountain so I want to change gears and was looking at 4.11 to 4.88. Its a summer toy so just around town and to the mountain and dont care about top end, 60 would be plenty for top end. And please no suggestions of swapping trans or new atlas or axles, so on and so on. Thanks for any input

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Unread 01-20-2010, 09:20 AM   #2
JoonHoss
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IF you don't care about top end, 4.88's would definitely get you plenty of low end, however, if it were up to me, I'd go with 4.56's unless you plan on going to 35's at some point. 4.11's is almost too small of a change to be worthwhile, IMHO.



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Unread 01-20-2010, 10:12 AM   #3
greeninwyo
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Ya I thought of 4.56 too and like I said I have to drive it to the mountain so wasnt real sure of the top end on 4.88



thanks
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Unread 01-20-2010, 10:19 AM   #4
CSP
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Another option is try to find another '72-75 with 4.27 gearing. My '75 had 3.73's also and I found a pair of axles from a '72 that I swapped in with 4.27s (optional ratio in '72-75). I found them to be about perfect for 33s.

Use this link to determine what your RPM's would be with different ratios.

Gear Ratio Calculator
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Unread 01-20-2010, 01:04 PM   #5
greeninwyo
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OK thanks CSP might be hard to find in wyoming but Ill check around
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Unread 01-21-2010, 06:54 AM   #6
jeepdaddy2000
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for the cost of gears, you could do a T18/SM/NP transmission swap. This would net you much stronger transmission, the crawl rate your looking for, and retain your ability to drive the Jeep on the road.
You could also look at a transfercase reduction set.
Just some options.....
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Unread 01-21-2010, 08:01 AM   #7
Fjguercio
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I am kinda in the same boat... I have a 3 speed road with granny gear... a T18 with 3.54 stock gears and 33x12.5 tires. The road for me is fast but mpg is good if I feather the gas with a vac gauge. The granny allows me to do the mild type of off road nice. I am changing to 3.73s from 1974. If not for the granny I would be doing the 4.09, 4.10, or up to 4.56. Hwy cruise is 2400/2500 now and do not want to change a lot.

I like the idea of changes to transfer gear case mentioned above... that would be the easiest change and net the results you have the issue with, too fast off road... but its 2:1 stock changes to 2.46:1 and 3.15:1 in low are avail

The other thing... If you have a really nice CJ same to start changing it up a lot??

Here is a gearing calculator that does side by side compair and has all the trans ratios per gear and Transfer Case.
Great Calculator and side x side comparison
http://www.grimmjeeper.com/gears.html
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Unread 01-21-2010, 11:26 AM   #8
80cj
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greeninwyo,
I can relate to what you're saying. I had a 76 CJ-5 with 304, 3 speed T-150, D20 T/C and 3.54 's with 32's. What a lousy combination. It was a good highway and beach Jeep--forget the mountains. I sold it for my present 80 CJ-5. Your 3.73's are OK with 33's and make for good highway gears. In your situation, I would look for a T-18 with 6.32 gears although the quickest solution would be a transfer case gear swap.

Last edited by 80cj; 01-21-2010 at 11:37 AM..
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Unread 01-22-2010, 08:15 AM   #9
greeninwyo
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Jeepdaddy thanks for the help there both about the same price to do (gears/transfer) I checked it out and my current crawl is 285 and with the transfer kit would be 184, Im assuming that is pretty noticable? I think I might opt for the tera kit. Was wondering what you think of the Spartan locker by Yukon if you have heard good/bad. They seem like a pretty good locker for $250. Thanks for the help

Fjguercio- thanks for the gear calculator

80CJ- ya I still pull my hair out over my 75 from time to time but I got so much time/money in it now hahaa
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