compatible axles?

[mike1970cj5]

my 1970 CJ5 has drum breaks and i was wondering how can i tell if i have a dana 25 or 27 diff and axle. the guy who i bought the jeep from gave me a dana model 30 front end, but it has all the parts to put disk breaks on it. what would i need to take off the dana 25 or 27 and put on the newer Dana 30 . I dont know if the rear axle come into effect at all and if it does will i need a new rear axle as well if im to put the Dana 30 on??

 

[Old Dog]

I dont know if the rear axle come into effect at all and if it does will i need a new rear axle as well if im to put the Dana 30 on??

You need to be sure they are the same gear ratio.

 

[mike1970cj5]

any way to find out the gear ratio?????

 

[LongHorn]

any way to find out the gear ratio?????

The most accurate way is to pop the cover count the pinion teeth, count the ring gear teeth. Then divide the pinion into the ring gear.

 

[LongHorn]

A ballpark number can be had by jacking up the Jeep setting it on jackstands, then making a chalk mark on the drive shaft & one on the tire.
shifting into neutral you count the number of times the driveshaft turns to one rotation of the tire. l

 

[BajaEdition]

Mike, in order to get that Dana 30 under the jeep with new disc brakes is not going be a common swap. You will need to set up the MC for Disc brakes also. and a few other options are going to be needed to be addressed. such as steering linkage. I would first set down a list of mods already done to the jeep.
Such as, does it have the original Ross steering, or been converted to Saginaw or other form yet?
I am just trying to get the most cost effective way to go with this Jeep as we have discussed in PMs.

 

[CJ]

Two rotations of the tire if it is an open diff...