I have an 85 s10 blazer with a 10 bolt rear. Im pretty sure it has the stock 3.73s in it but i want to run 4.56s. Do i have to buy a new carrier in order to do so? Also i put a dana 30 out of a jeep up front. do i have to change the carrier on the front in order to run 4.56s? If i do can i run 4.11s without changing the carrier? if i have to im going to run 4.56s but would like to know if i can get away without having to do so by running 4.11s.

 

Welcome to the forum.

Are you sure of your current ratio. Alot of 1st gen blazers came with 3.42 gears but a good bit did have 3.73. Yeah you can get 4.56 ratio for the jeeps dana 30 and also the factory blazer 10 bolt 7.5/7.65 inch axle.

Or you can get the 4.10 in both axles. Or 4.11 in both axles but the diffrence is so small that it wouldn't really matter between the 4.10 and 4.11. Just whatever you get the best deal on. What size tires are you planning on running? Is this a daily driver or a off road toy?

I'd find the 4.56 ring and pinion and e-mail the company with your situation and make sure that it would work. I think to run 4.56 in a 10 bolt you have to use a reverse cut(?) gear set. Just seems like something I heard. I know for a fact you can run the 4.10/4.11 in the 7.5 cause the 4 bangers came with them. (Also my 92 s-10 blazer is at my mechanics shop getting the 4.10 gears right now )

 

I have 33/11.5 x15 tsl's. I think your right about the 3.42 ratio (i have a 2.8 If that matters wich i think it doesnt). I want to run 4.56s in the front and rear to get more power (and there cheaper then 4.11s which you can get for both axels) and take as much stress off the running gear as possible. its a daily driver and i dont wheel it much (when i do its not extreme like i did with my rock buggy), i use it for search and rescue, hunting, fishing, exploring wilderness, etc. I wouldnt mind running 4.11s if i knew wether or not i had to change the carrier.

 

No I'm pretty sure you can run either ratio in the 7.5 rear axle and 7.25 front IFS axle. Just check with the company you order the gears through or the manufacturer of the gears to be 100% sure.

With a 2.8 v6 and 33's. You could run either but maybe the 4.56 would be better since you don't have a lot of HP. (Not being mean or nothing, my 92 4.3 only makes like 120hp or so.) If you have a manual, 4.10's might be enough since they are more efficiant than automatics. Since it's a daily driver, I'd say 4.10 with the 33's would be better for interstate speeds, 60 and up. But if you rarely run interstate and mainly 60 and under. Mostly city and off roading, then 4.56's might be better for torque and power with interstate mpg dropping cause of higher rpm's. But it's up to you and what your needs are.

Good luck with the swap and tell me what you go with and how it turns out. Just a side note, if you get a "kit" like the one I got from Jegs with the ring and pinion gear set and the install kit. Most don't come with axle seals and bearings. And with it being a older model it'll probley need them. My mechanic doing my swap called me and had me pick some up cause mine were showing some good wear. Both seals and bearings were only $40 at advance with no discount. Napa wanted $55 with a company discount. Unless your going to a shop to have it done and they have the parts for cheaper. I'd go ahead and pick them up. If you by chance don need them you can return them. Might save you the trip I had to make today.

 

Well i got the axel in today and did the rear spring over and had to make 4" longer shackles in the back to match the front! I used the rear springs from a 94 blazer up front and i must say that 33s look way to small now! I really didnt intend on haveing this much lift. I think im gonna need 5.88s and 37s now! Is that a good ratio (37s and 5.88s)?"



Oh and since im new and dont know where to post this little tip but here goes: Get Hitch and reciever square tubing and cut the ends off your front driveline and weld(with 220 only) them to end of your tube (make sure they are straight). Pull measurements and cut the tube so they slide in eachother and presto you have a low budget front driveline that you dont have to worry about maxing out! oh and if you want to get crafty you can drill and tap up at the top and install a grease zerk so you dont have to pull it apart to grease.

 

Too much lift, I didn't think that was possible! lol I wanna see this rig. 5.88 would be a little stout if your gonna have it on the freeway. If it will see any highway speeds and yo want some mileage, go with 5.13. If it is just a 4x4 monster, go for the 5.88.

I really want to do this on my 92 blazer. Maybe next year.

 

Ill gotta find my camera and ill post some pics

 

So i just called Randys ring and pinion and they had the answer i needed. they make 2 different gears depending on what carrier you have. now i know i have to buy a new carrier for the front and i dont in the back to run 4.56s.

Thanks you guys for the info it was a big help