Re Gear

Re Gear

Rube83

Jeeper
Posts
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Location
Nebraska
Vehicle(s)
1983 CJ7 - I6 - T4 / Dana 300
Spartan up front and rear
4.11's
4" SUA Lift
33x12.5 TrXus STS
HEI
I am going to be re gearing my 83 CJ7 this winter and I need some help with a couple questions. When looking at gears for the Dana 30 , I see a lot of gears from the early 90's on - Did the Dana 30 change for some years? Will any of those work/not work? Also, are the gears different in a HP? Thanks.
 
Before the gas crunch the factories would often put in very low gearing.
Don't get used gears. Randy's Ring and Pinion is a good source of gears and axle parts: http://www.ringpinion.com/
They are very knowledgeable and will make sure you get the correct parts.
Here's a chart to help get the correct gearing.

_35422.jpg

This shows the tire size vs. gear ratios. The numbers in the middle are the engine RPM at 65 mph. Shoot for gearing in the green for the best compromise between power and mileage. You may even consider going slightly into the yellow for high gas mileage. Red is low gearing but I would stay away from those gear ratios unless the jeep is only for off road (not street legal)

Then the YJ and the Cherokee has a high pinion. The HP gears are cut differently.
131_1107_08+how_axle_gears_work+high_pinion_and_low_pinion.jpg

The teeth of all ring and pinion gears have a drive side and a coast side. Theses teeth are angled so the drive side of the gear is stronger. Because of this the low pinion is stronger in the rear and HP gears are stronger in the front.
 
Last edited:
X2 on what dave said.
You will need a standard roation, low pinion set of gears for the front diff.
 
....But be careful here... After a short stint using reverse cut high pinion gears in the Dana 30 (YJs), the standard cut came back into existance for the TJ's Whether or not these gears are compatable with the older CJ Dana 30 someone else will have to answer...but I suspect they arent because of the vast difference between the TJ and CJ Dana 30 .

To eliminate confusion, reference parts for YOUR year. :cool:
 
Thanks for the info - The reason I asked was there were a couple posts on Ebay for new in box R&P's from other jeep styles in '90 to '95 for the Dana 30 . Is the TeraLow kit a viable option? That way I will have a lower geared set up already in place if I ever have to switch axles at some point.
 
Rube83, the Tera Low kit is a great addition. I have one in my rig and it is quite good for crawling. It really multiplies the torque to the axles, so you will have to consider that.
 
Need to think about what tranny you have as well before you decide on what gears you want and if you run the Tera Low kit. I'm swapping in a T-18 and 4:56 gears. My crawling rate will be in a nice high 75's! Most jeeps are running around high 20's to 40's. You also need to think about what type of wheeling you do. I don't do much rock crawling but just wanted a better tranny to put behind the motor swap and I wanted better road and off road manners.

Now I have a AMC 150 with a T-4 behind it and running 3:54 gears on 35's shoes.

I'm installing (hopefully over the winter) my rebuilt AMC 304 with a T-18 and 4:56 gears. That will put my RPM's right where I want it for hwy and wheeling.

This chart will also help you...

BC4x4.COM four wheel drive, 4x4, offroad and fourwheeling site.
 
Is the TeraLow kit a viable option? That way I will have a lower geared set up already in place if I ever have to switch axles at some point.
The TeraLow kit will only lower your gearing when you are in 4 wheel drive Low. You still need your axles geared to compensate for your tire size.
I installed a TeraLow kit and love it. The TerraLow kit costs about $1000. It replaces every gear in the TCase but it's easy to rebuild the Dana 300 (or any of the other CJ TCases)
 
Not many rocks in Central Nebraska so we make due with the river - Lots of quick sand and such - And the lower gear the better. The guys in the high 5's in gearing can always get out even when they drop into the quick sand - The constant slow turning lets the sand come back under the tire and they pop right out. And i like the fact with the TeraLow kit that you have normal driving speeds in high. This really is good info from all of you and I appreciate the help. There are always 50 options according to personal opinion but it helps to see all options when building what fits me.
 

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