Re-gear

I’m looking to re-hear my CJ. I’m debating on 4.10 or 3.73. I’m running 32” tires on a d44 and d30 NT and a 225 motor. My question is are these RP high or low pinion? And I drive it on 90% road but if I want to go with a wider tire I’m thinking 4.10 but leave room for slight Highway driving. My near future for this jeep is to run a V8 in it so these gears are kinda in between what I’m looking for I believe. Any assistance on this would be great. My 5.38 gears are just too much for my driving

 

Are you running the original Dana 18? How about an overdrive and keep the 5.38 gears?

Unless you've got some custom axles, I don't think high pinion axles exist for your application. Should be obvious looking at the axles. A high pinion axle places the pinion axis above the center line of the wheels. Low pinion below.

It would be helpful to put the year/model/equipment in your signature file; then it will appear in each of your posts.

 

Currently running 31" tires and a dauntless.
I switched from 3.73's to 4.10's when I did my T18 swap.
IMHO the 4.10's are a tad low for street driving. This has become a bit disappointing since the transmission swap cured the first gear issue.

 

I've got a Buick 350 V8 with a T-18, D-18, Warn OD, 3.73 gears, and 32 inch tires. With the stock D18 low range and the T-18 it gives me a 58:1 crawl ratio and 2.8 highway gears in overdrive. The torquey Buick 250 seems to love these gears but I've not tried any rock crawling with it yet.

 

I have a 71 with factory drive train (plus OD); 225-V6, T14, D18, 4.88 gears and Warn OD. I have 30 x 9.5 tires. I love the combo. Freeway speed of 60 to 65 is no problem. Plenty of wheel spin for sand and it did great in Colorado 2 years ago. I still have carburetor and points in the distributor. I have not done any rock crawling, just not my thing.

 

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I’m in a 62 M38a1 body with 66 225 oddfire motor with D44 rear and D30 up front but is currently not installed. Currently T90 transmission but hav 420 I’m rebuilding to put on a V8 when time comes.

 

Stock 225 gearing was 3.73 standard, and 4.88 optional, so anything in between will be OK. 3.73 gearing will be more road oriented, and the steeper gears will favor off-road/trails. The width of your tire make little to no difference in gearing, but diameter/height does. A future V8 will have more torque than a 225 V6, so will pull the 3.73 gears more easily, as noted by Fireball.
As mentioned. High pinion is found on much later vehicles and as Tim noted, the pinion casting is higher than the axle centerline.
-Donny

 

I run 4.27s behind the 225. It's on 35s with no overdrive.

 

Thanks for that info. I like the OD option but if I’m swapping the 3 speed out I don’t know if OD is an option, so I think 3.73 May me my answer. I didn’t know the 225 came stock with 3.73, plethora of info on this site.
!!!!

 

The overdrive depends on the original Dana 18 transfer case. If you plan to keep that, you can have the overdrive with any transmission that will otherwise fit. The main constraint is the rear driveshaft length. A 5- or 6-speed overdrive transmission, and nearly all automatics, are too long for this chassis without some heroic mods. The truck 4-speeds are popular, but you can go a whole lot of places with the original 3-speeds. Deep axle gears, the original 3-speed, and an overdrive would be a lot of fun, and get you on the road with comparative ease.

The V6 Jeeps were 3.73 standard, 4.88 optional. The majority of F134s got 5.38s, though 4.27s were available in the latter half(?) of the run. Jeep switched to 3.73 standard and 4.27 optional for the CJs in 1972.

 

For the most part I’m sticking with original D18 but swapping to 420 transmission. If I went to original 3.73 gears for the dauntless 225, it may be more favorable for me. Just one less stick I have to worry about and reading that if I have OD in gear too long it may be worn out sooner. I live by a lot of 45-55mph roads, so OD would be in gear a lot I presume. My final jeep will hope to be 5.3L with sm420, d18, 3.73 gears in D30/D44 on 33”

 

I'd also recommend the OD. Super easy install. My '69 is the stock 225, T-14, D-18 w/OD and 4.88's. I'm running Deestone D503 - 7.50x-16's which are about 31.5" tall. It pretty much lives on the street and I think the gearing is perfect. It'll do 60-65 no problem. I am planning a T-18 swap in the near future though, just to get a lower 1st and replace the failing T-14.

 

The Warn OD's are rated at 300 ft-lbs and I suspect that held for Saturn. IMO, the Warns will take a good bit more than that if you drive reasonably. Mine stayed alive behind both a not-so-mild 350 and a 381 for better than 3 decades. It is still in the 3B but I suspect it will be leaving soon as jpet's D18 gears will not work with it and the current sbc will be making almost twice that torque rating. I ran that with 4.10 gears and the sbc's were just loafing down the road at 75 mph.

 

I may start with a re gear 3.73 and see how it runs with that then May think about OD with a 420 tranny and 18 TC. Along with a 5.3 because of fuel injection and more available parts. But regear is a definite I think for me. I’d like cruise speed at 65 but not for more than 20 min just to get to work and back.

 

If you re-gear with 3.73 gears, an overdrive probably won’t be needed. You should be fine out on the road with 31” or larger tires. An overdrive is a benefit with much lower gears, like 4.88s. I ran an overdrive for a while with 4.27 gears, and it was not really needed.
-Donny

 

Those arrived at least a decade earlier. I bought my Warn OD for the CJ 5 in 71. It was a nice even $200 plus $5.00 shipping-still have the receipt. The one for my 3B was installed in 1975. I've had no problems with either but there are a couple of 3 decades+ old Warn rebuild kits still hanging on the shop wall.