Woah.... What Axle Ratios Are In There????

Just finished a clutch job on our 70 CJ5 225 project and took her out for her first spin in two years and woah....... We're not sure what axle ratio we have or if its the new clutch but as soon as she engages its like a hole shot right off the drag strip! Its like there is no slow start off just unreal torque and extream acceleration. Is this just the difference in a 134 and a 225 or does a low axle ratio give it that kind of off the line power?

 

My 67 with 231 and 4.88 gears is like that. I have the advance adapter chain clutch controller also, don't know if that has anything to do with it. Seems like sometimes the clutch just grabs and the Jeep lurches forward chirping the tires. Even after driving this thing for 5 years it still catches me by surprise sometimes. And it is not a to high idle (650-700), or an oil soaked clutch (blew the motor and everything is out for repair and inspection, clutch is fine). I know exactly what you are talking about!

 

it's those damn diaphram clutches breaking over center. Borg & Beck clutches are (smoother at takeoff) with mechanical linkages but require more force to operate and therefore tend to break mechanical linkage parts more often.

JB

 

Easiest way to tell the ratio is to jack up one front wheel with the hubs engaged and the jeep in 2wd.

put the valve stem at the 12 oclock position.

make a mark on the drive shaft next to the differential housing.

Turn the wheel 2, yes, count 'em 2 full revolutions and count the number of revolutions of the drive shaft. That'll be your ratio.

 

I've got 4.11's with 33" tires and the same problem. It is something that you get used to. If you're out on a trail ride and you let your rider take a turn at the wheel, try to remember to warn them what's about to happen the first time they let the clutch out - or don't warn them and just hold on tight.

I wonder if you could build a chain & sprocket setup with an elliptical (or other) shaped sprocket that would vary the speed of clutch movement so that it would slow way down at the critical point of engagement. Sounds like a good design project for a student mechanical engineer. Just thinking out loud.

 

Sparky, that tech link you posted isn't entirely accurate. As Kamel noted, one wheel should be on the ground if you are checking the ratio of an open differential. otherwise you could get a false reading.
Per my experience, here is what I do (don't take this as gospil)

Determine if you have an open differential or some sort of locker/limited slip.
do this by jacking the rear end up (both tires off the ground). spin one tire in one direction. If the other tire spins in the opposite direction, you have an open differential. If it spins in the same direction, you have a locker/limited slip.

If Open - jack up rear end (one tire on the ground). spin the tire off the ground 2 full revolutions. however many times your driveshaft completes a revolution is your ratio.

If Locker/LS - jack up rear end (both tires off the ground). spin one tire 1 full revolution. however many times your driveshaft completes a revolution is your ratio.

All above is done with the transfer case in 2wd.

can anyone confirm this method? anything i missed? i see this question come up a lot and i think the above explanation clears up any confusion of what is posted in the tech section.

 

They came in 4.27s (mine has these), 4.88s and a 5.??. They are gear LOW and crawl over anything. My brother has a 1978 with a strait 6 and mine with the 134 will out climb/mud it due to the gearing. However, you pay the price with a 50 -60 mph top end.