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so i got my lift and 33s, and i really want to change the gearing to compensate for the extra weight. i cant decide between 3.55 and 3.73 (kinda leanin towards the 3.73) i dont do much interstate driving, just to work and back then some off-roading on the weekends.
Which should i go with?
second question, when i do get the new ring and pinion, how hard is it to change? i am mechanically inclined and so is the guy thats gonna help me, so i figure we could do it. neither of us have changed the ring and pinions before. i have a hanes manual for a little help, i just wanted to know if there were any tricks to the trade, things to watch out for, etc from the guys who have done it before.
I'm thinking either 3.73's or 4.10's. I would not even consider 3.55's.
I'm about as mechanically inclined as anyone is. I've swapped engines, transmissions, done clutches, and I would take mine to a shop to have gears done. There are some special tools you need and if you make a tiny mistake your whole axle will end up trashed. It's not worth it IMO.
4.56s all the way! Changing out a set of gears is rather simple.. *usually* you can use the shims that are in the axles from the factory and get you really close to where they should be.. you might have to pull the gears out acouple times to get it set right.. If your not putting all new bearings in the rear axle, make sure you buy a shim kit for it.. I only had to change out some shims between the carrier and housing on the 8.8 when I did mine. the pinion depth was spot on.. Heres a little trick for the TTB front, when you put the bearings on the carrier, leave some of the shims out. and when you slide the carrior into the housing, to get the backlash right, use some of the shims for the 8.8, ans install them betweem the race and housing. It makes it alot quicker and easier if you are like me and dont have "setup" bearings..
Changing gears can get pretty involved. do a google search for "gear setup" in google for whatever axle you have. 9 inch would probably be the easiest to setup (still requires a pretty solid understanding of what you're doing though). 8.8 and full float danas have pretty much the same procedure.
It's not particularly hard......once you understand the concept of what you're doing. Thats sort of like saying C++ computer programming is pretty easy once you understand it though. A lot of people flat out refuse to understand what is going on with gear setup though. Read a LOT about it though, there's tons of writeups for all kinds of different axles out there, and they all have helpful information.
If you were thinking you can just buy a new ring and pinion, take the old ones out and slap the new ones on, then you're mistaken. There's bearing pressing, and all kinds of measurements and adjustments that take a high degree of precision to do right.
i have a 95 reg cab 2wd with a 300 and mazda manual tranny. i was planning on replacing as many bearings as i can when i do it. i would be at the hobby shop on base (i dont have my own shop in germany) and i know some mechanics that work there that could help me out. ive searched on google for some detailed instructions, but everything is pretty vague, anybody know a specific place with some detail? maybe a few pics or diagrams?
4.10's all the way. Im running 3.55 with 33" and you can defiantly feel them. 3.55 actual ratio with 33" tires gives you a net rear end ratio of 3.08 plus the weight of the tires. It has power, but it would be nice to bt a little lower.
I want to go to 4.10' with an ARB in the rear this summer.
my uncle runs 3.55 in his truck (300 I6 mazda 5 speed) when he puts those 33's on you can defiantely feel it...but for 33's i would not go over 4.10...if you do a lot of highway driving in mostly flat areas go like 3.90 but if live in hill country do a lot of towing or just dont do much on the intertate go 4.10
...i just got my 4.56 gears for my solid dana 44 and ford 8.8 hopefully get er done this weekend ill take some piccys for ya...its fairly easy once you grasp it...its the measuements that confuse everybody...but the factory shims ***should*** be good...but always have a shim set on hand you dont want to screw up and blow out your new gears...the only "special" tool you need is a sial indicator to measure the backlash (the ammount of the the ring gear has side to side on the exle) which means how far it can move towards/away from the pinion gear.. its supposed to be between 0.08" and 0.1"
other than that the pinion get should be pretty good with the factory shims but still measure that from the center of the ring gear to the flat spot on the end of the pinion gear...
Backlash isn't a side to side movement. Its how far the ring gear can rotate without the pinion moving. There shouldn't be ANY side to side movement odf the ring gear.
i appreciate all the input. im gonna do some more research and ask around at the auto hobby shop on base to see if any of those guys have done it before.
i dont wanna pay somebody around here cause the german shops charge boo koo money to work on american vehicles
I assume you have 3.08's now since you are looking to go 3.55 and 3.73. All I can so is DO NOT GET 3.55's. I've had a truck with 3.08's and 3.55's. The 3.55 truck ran 31's just fine, but I even noticed going from the 29's to the 31's.
3.55 gears with 33 tires is about the same ratio as 3.08 gears with stock 235/75R15's, but you still need a bit more to get the rubber rolling.
I've got 3.08's and 31's now and I turn 1750rpm driving my truck 75mph. I have to speed up to 80 to prevent downshifts in the mountains (and that's with a 351). Go to a 3.73 minimum. That's where I'm going when I up to 32" tires.
Check out this website (Calulators from www.4Lo.com), I would say that 2000rpm should be you minimum target rpm at your preferred highway cruising speed.