The Chrsler 7.25, 8.25, 9.25 it is the diameter of the ring gear of the ring and pinion gears within the axle housing.

 

and some other small stuff like width overall and shock mounts, can;t forget major stuff like that when transplanting...

The 9.25 was on just about all the gen2 trucks if I remember right, rams i'm not sure about but they were on all the Durango's. If you got trucks like that available for pickens with good parts, might be your best bet.5 lug axles could be pulled from a jeep, but not entirely sure about the spline being the right count. Can't remember off-hand if the 9.25 was a 29 spline axle or not, I know the 8 and 7 are 27 spline.

 

The 9.25 only came on a few 2nd gen Dakotas, and 1st gen Durangos. Probably mostly only the R/Ts with the 5.9 V8. They all have the 6 lug axles. 96-down 8.25's were 27 spline. 97-up 8.25 were 29 spline.

 

Ah thanks for the correction.

 

Sounds like 7, 8 & 9 are my gear ratio's then right? Or just a larger pumpkin?

If I find an LSD on a Jeep or Dakota is it guaranteed to be an 8.25/9.25 or did the 7.25 come in an LSD option as well?

 

No that is not the ratios, just the SIZE of the ring gear. For your or any axle ratio you spin the tire 1 revolution and count the number of turns the drive shaft spins. Dakotas came stock with 3.21:1, 3.55:1 and the best 3.9:1.
Some Jeep's mostly only Cheerokees came with the Chry 8.25 but I don't believe with the 7.25 and not the 9.25. Like I said find a Dakota not a Jeep.

If you need to know how the axle works just to identify it check out www.howstuffworks.com

 

Thanks!

So if that is not the ratio it more-less determines the strength of my rear end? Bigger ring gear = harder to break? Sorry if I sound like a little girl haha I'm learning!

I will stick with Dakota then, I can't believe someone like Jeep never offered a 9.25 but does it have to be a pre-97 Dakota?

If the best and most punchy is 3.9:1 then that is what I will search out if I am going to do this. I have a lot of narrowing to do starting with LSD then 9.25" then 3.9:1, is there anything better than that to look for?

 

Jeep didn't offer the 9.25 because it didn't have any strong enough engines which would require more HD axles.

If your looking to keep your 5 lug then 87-90 Dakotas. Other wise a Jeep axle is the next choice for the 5 lug.

If you don't care about 6 lug you can get 92-09 Dakota's. You can always swap front rotors for the 6 lug up front.

 

Someone is saving me a set of 1979 AMC TurboCastII wheels so I need my 5-lug pattern. Can I just put axle shafts from an 87-90 in an 92-09 axle? That way I could find a newer axle itself

Can the "ratio" be swapped out if I found a 9.25 " LSD with a different ratio? I figured the gears could be easily shipped through eBay if I needed them.

 

between the 8 and 7 axle you should be able to as long as the lengths are the same and they are the same spline, otherwise I see no reason why you couldn't.