My current axles are 30/35 with 3.07 gears I believe. I have an 89 yj with the 4.2 engine and ax-15 tranny. I have 33" tires on and love them but I can't use fith gear anymore. Should I find a set of 4cyl axles to get the 4.10 gear ratio? Please advise.
You should have 3.55 gears, not 3.07. The 3.07 is usually for the inline-6 automatics. 3.55 is usually for the inline-6 manuals, 3.73 (or whatever it is) is for auto inline-4's, and the 4.10's were used with the inline-4 manuals.
Now, I had 3.07's with a 4.0L and used 33" tires. When I swapped my Dana-35 to a Ford 8.8, I switched it from 3.07's to 4.10's. And I absolutely loved the transformation. It accelerated like an actual car and not like a '84 Corolla.
My advice: If you're going to regear, I would most certainly just replace your Dana 35 with a Ford 8.8. I bought mine for $250, I got the mounting hardware for another $150 or so, had it welded on and I couldn't be happier.
As for the front... if you plan on doing the regear yourself and have a full solid weekend to dedicate to regearing the front [as well as a lot of time to research, read, and research some more], then I say get the kit. They're about $250 bucks, and it comes with a new ring, a new pinion, new bearings and new shims.
However! YOU WILL NEED A NEW CARRIER!
I can't stress this enough, as I forgot I needed one, and I ended up ****ing up my brand new gears.
The proper carrier is, I believe around $80 bucks. Now, you should most certainly check your areas junk yards for possible swaps out of manual inline-4's. Rather than regearing myself once more, I decided to get a whole axle for $400 dollars. It came with a spare set of brake calipers, spare axle shafts, spare knuckles, spare cover, etc. You end up getting a lot of things you can use later on (if you have the room and the desire to store them).
It also makes everything much easier. Where as before you had to set up everything, this is just drop your front springs, remove old axle, put in new axle. Fin.
That's just my $.02
Recap: My advice is to not touch the Dana 35, and to upgrade the rear to a Ford 8.8. (The Ford 8.8 is much stronger than the Dana 35, and even stronger than the Dana 44. The best matching Ford 8.8 is out of early 2000's Ford Explorers. Some even have LSDs.)
If you plan on doing the regear yourself, you can get a kit but remember to get a carrier that will fit the gears
. If you want to, you can also replace the whole front axle and get spare parts.
If you plan on paying someone to regear, I've heard some people get quoted $1200 dollars. But I can't say for certain how much it is for someone to regear your axles.