70 CJ5 Ring and Pinion Questions

Ok, I found my problem with the whole being titled in 71 deal. I found the tag on the dash, date of manufacture was July of 1970, why is it titled a 1971? But thats not the issue. I searched the forum but didn't find the answer I was looking for. I have the stock 3.73 gears in it with the powerlock rear axle option. I'm running 38.5x15x15 tires on it w/ 4" suspension lift thinking about a 1" body lift, and yes they fit . Now the question, would it be beneficial to me to run 5.38 gears? I know the bigger the tire size, the taller the gear and the two offset each other so you're not redlining your engine at 40mph. I'm running the mighty dauntless 225 V-6, T-14/18 single stick, 4 barrel intake, HEI conversion, Edelbrock carb other than that, not too beefy. So if it would be beneficial to run the 5.38 gears would they fit in my stock carrier or would I have to buy different axles? Also, what axles do I have front and rear? I'm completely clueless to this aspect, new to Jeeps. I found some gears from herm for a good price. Also what are thick gears?

 

The 5.38 gears wont fit you carrier unless you get a set of thick 5.38 gears. as far as changing the carrier it will fit your axles . not sure what axles model you have, maybe some else can answer that.

 

To be perfectly honest I have no idea how your rig is running at all with tires that big and gearing that high, you are affectively running stock diameter tires with around 2.8:1 gear ratio, if you put 5.38 gears in there your gonna feel like you added 75 horsepower to your rig.
You should have a dana 27 closed knuckle up front and a flanged 1 piece axle dana 44 in the rear. You will need all new carriers for both front and rear axles to put the 5.38 gears in. At 60mph I would bet your motor isn't running more than 1900rpm which is way way to slow for this motor and that tire combo. It should run about 2400-2600rpm at this speed.
If this thing gets into to much rough stuff that front axle is gonna puke pretty easy with those tires, to be realistic most guys don't recommend tires bigger than 32-33" for a dana 27 and 35" max for a dana 44. So you can see how much oversize those tires are. If it was mine I would get rid of the 38.5" tires in favor of some 33" tires, as you would notice a whole lot more control of power with the smaller tires because of the gearing issues and how fast your engine was turning and how much gas you would have to give it compared to now.


Your jeep was probably a holdover from the factory that didn't sell in 1970 so it was titled as a 71 model.

 

The OE's typically change over model years in the summer in order to have inventory at the dealer's in time for September "official" new model year announcement. It's silly actually Now days, it happens over the 4th of July timeframe. In some cases, if CAFE (Corporate Averaged Fuel Economy) is an issue, they will postpone changing the year in order to produce 4 cyl cars /trucks through December. This makes the average work out better. My question is, what about next year?? You have "borrowed" or "spent" next years numbers!

I don't know how Jeep did it back then but AMC may have started it. My '70 was manufactured August of '69.

 

I thought the individual state titles were based on the manufacturer's statement of origin (MSO) provided to the dealers and it was this document that was used to acquire a state title. If so, wouldn't the MSO accurately describe the year of manufacture, coinciding with the VIN tag? Jim (jpflat2a) can probably shed some light on this. Jim?

 

sorry I am no help; I was never in the sales end of it; my dad would know.
I remember June being the cut-off date for current year orders, as the new year models always seemd to arrive in August/September
we had a 1972 Commando V8 in stock that we moved with us to our bigger facilty in November of 1974; it sold (finally) in Dec 1974; but of course it's a 1972, first sold in 1974, and the title would show that.
We did some warranty work on a new 1982 Scrambler (4 cyl) that Brian Chuchua sold new in 1985; warranty didn't start till vehicle was sold

 

I agree with Mike - that front axle isn't going to be too happy with those 38's. Especially if you decide to add a locker somewhere down the road.

If you're going to re-gear, and in this case, purchase new carriers - I don't think it's wise to spend that much $$ on the Dana 27. Also factor in the cost to upgrade the brakes (I have 32" tires and the 10" drums are marginal for those...).

Instead, I would look for a Dana 44 front out of a Wagoneer or Scout. Then, you're getting into another can of worms with swap-ability, caster, pinion angle, etc.

We're not trying to bash on your plans, just let you know that it's going to be a whole lotta work to get the 38's to live and be happy under an early CJ (did I mention the high center of gravity and short wheelbase?).

 

Can you even get gears as low as 5.38 for a d27? I remember the cutoff for the d30 being something like 4.56s. I too would look for some smaller tires, or build some bigger axles.

Kevo

 

5.38's were stock for a 27 with the F-head. You can get 5.38's for a 30 also but have to look to the aftermarket. Randy's R&P sells them as do other suppliers. Nickmil.