I have 89 cherokee with 31's tires and want get bigger ring and pinion 4.88 and i dont know what is my stock ring and pinion? My friend told me that my jeep has 4.56 gear i was no way cant be that big for stock dana, can anyone pls tell me what my stock ring and pinion size? Thanks,

P.s. My jeep dana is 30

 

Your front is a D30. The rear is either a D35 or a D44, i dont think the 8.25 was in them that early.

If you have an auto its a 3.55 gear ratio. If its a manual it has 3.07s.

4.88s are quite a big jump for just 31s. Do you plan on larger tires?

 

Size of ring and pinion has not much to do with ratio the pinion gears do get smaller the lower you go(numerically higher), its the the tooth count. Dana 30 is in the front, the rear most likely is a Dana 35, being an '89 you have slim chance its a Dana 44, Dana 35 cover is oval, Dana 44 cover is a funky hex shape.

 

I have a D44 rear.

 

You obviously were never told, that bragging is impolite, and down right rude!!

 

me too.
my diff is so big, it drags on the ground.

 

That's gotta be rough when it hits a rock, precisely why I like mine tucked up out of harms way.

 

What i was understand i was told if smaller ratio gear on bigger tires can cause gear damged if too rough offroad also bigger ratio gear has more power and stronger.

 

Did anyone every replace the ring and pinion before? Was it hard? Tell me how it was. Thanks

 

this should put it in perspective for ya
http://www.pirate4x4.com/tech/billavista/Gear_Setup/

 

Really awesome website alot alot of reading, will read all later on thanks for helping.

 

happy to help. good luck man. If you cant do it, I hear install is over $600. dont quote me on that

 

Leaving aside trying to decipher what you are saying above...

"Dana" is an axle manufacturer (actually, they do quite a lot,) and the size of the ring gear is keyed to the model number - you have a Dana 30 front end, and I'd almost guarantee you have a Dana 35 rear.

"Ring Gear Size" is the diameter of the ring gear in inches - which can be given directly (such as a Ford 8.8" or a Chrysler 8.25") or keyed to model (the Dana 44 has an 8.5" ring gear,) or can be figured out from a limited number of selections (there are two or three versions each of the "GM 10-bolt," which refers to the number of screws holding the cover down. I don't recall specifics.) As a thumb rule, the larger ring gear will be stronger (assuming all else is equal. Material plays a huge part in this!)

What you seem to be talking about is ring & pinion ratio - which has nothing to do with the diameter of the ring gear, as it is the ratio of the driven (ring) gear to the drive (pinion) gear, expressed as a ratio of "something-to-one." For example, a "4.56" ring & pinion ratio is properly expressed as "4.56:1" - the ":1" is generally implied.

However, you can have the same ring & pinion ratio with a number of different ring gear sizes - nearly every model of axle made has had a 3.55:1 (or thereabouts, sometimes 3.54:1, sometimes 3.56:1) ratio, with ring gear sizes ranging from 6" to 11.5"

As far as what ratio you want, it's going to depend on a couple of things:

- What is the intended purpose of your rig? If it's trail-only, then just go with the lowest gearing (highest numerically) you can get. If it's a street/trail rig, DD, or other vehicle where fuel economy is a concern:

- What engine, what size tyres, what transmission? You end up having to select an "optimal" gear ratio to give you a cruising crankshaft speed (engine RPM) at or near the torque peak output of your engine in order to preserve fuel economy. This will be affected/limited by the ratios available for your axles, but you should be able to find a useful ratio with your D30/D35 combination.

 

Wow u seem know alot stuff about ratio and ring pinion i just know very little, i just learning and hope u can help me out i want ring and pinion that good for off road but i do drive on road sometime not very much because of MPG, all i want better ring and pinion for offroading, can u help and tell me what the best? Thanks, hope hear from u soon.

 

The gear ratio is dependant on a few things:

1: style and purpose of driving the vehicle2: size of tires3: as 5-90 stated engine size

4: as 5-90 state transmission, automatic or manual