Just completed a ratio change on my 90 bronco last night. What a difference going form 3.55 to 4.10. I didn't go any lower becouse it's a daily driver and it's stock. It will stay in OD now so maybe fuel milage will go up a little. The old 8.8 started to sing and the pinion seal started to leak so I had to do some thing any way. So I decided to go to 4.10's. the bronc. drives a whole lot better It pulls hills better has better responce when you step on the gas. With the new shocks, stablizer bushings it holds the road real good. No more body roll going around corners and I'm not hitting my head on the window from bouncing around. The old shocks were wiped out. Icould beleve how bad they were!!!!

 

I'm thinking of doing the same thing. What size tires do you have and which motor tranny? I have a 92 with a 302 and 31's, 3.55 gears. It is quite the dog, gets horrible mileage in town but up to 20 on the highway.

Thanks,
Biederboat

 

My tires are 31's,5.0 and a AOD tranny. I was getting around 10 mpg before and using OD was rare. I dont know what my milage I get yet. Preformance is better, there is a hill on my way home that it would kick down to second to make it.It will now do it in third and I have to let off a little becouse there is a curve at the top. It's not cheep to do tho. You have to get your ring & pinion the ring gear case for each diff. I think ford should have put this ratio in not 3.55's. I got away cheep becouse Igot it threw were I work. Also I put a limited slip in the rear.

 

Wow, sounds like my exact set-up except I'm still stuck on 3.55's. I would like to know how mileage is, city, hwy and towing if you do any. I know it might take you a while but if you could send me a message when you know I would really appreciate it.

Thanks!
Biederboat

 

Biederboat,
I'm going to fill her up tomorrow. I don't do a lot of highway driving with it. My drive to work is about 20 miles up and down hills, in and out a couple of small towns and some straightaways long enough to get into OD now. I might take it to Bloomsburg Pa. in July for 4x4 jamboree. My nephew runs in the Micky Tompson tuff truck series. I take my son there. From there we will head to Cape Cod to meet up with the rest of the family. But I'll let you what my milage is before that.

 

Yes I would be curious to know too. I just found out I have the 4.10 gears and my gas milage has never been better than 10 miles to the gallon. but I have 33"x12.5 and a C6 trany. I am trying to decide if I need to get another trany with OD.

 

when you change gear ratios, don't you have to match your front differential to your rear?

And did you say you have to change your differential case also?? I thought you could just take out the old ring and pinion gears and stick in your new ones.

 

how much did you spend on parts? I have been wanting to do the same...

 

Yes you have to do the front also the Dana 44 will have a 4.09 ratio. There are different diff cases for different ratios. becouse of the different thickness of the ring gear.The lower the ratio (the higher the number) the ring gear gets thicker becouse the pinion gets smaller.So the diff case what the ring gear bolts to has to be a different height. My cost to do the the change was very cheep what new parts I bought my employer gave to me at cost. The front diff was hanging so long with no sales they gave it to me. I took it apart cleaned it up and put new seals. while I had it apart I put 3 new axle u-joints the,axle to hub seals,the hub needle bearings andwheel bearings and grease seals. The bearings, seals andU-joints were about $120.00 One thing check your axles real good for the rear drive axle (the 8.8) they wear out where the axle bearing rides. I had one that was pitted real bad and the other was just starting to pit. All the ones at work were bad so Igot a pair from the local salvage yard for $100.00 You can get new OEM's but they are a round $150 to $200 a piece. There are aftermarket ones but watch out some are poor quality.

 

Yes you are suposed to change front and rear gears at the same time.
You only have to change the carrier inside the case when you go to a certain gear ratio, which I think is about 3.92 and up requires a different carrier than 3.92 and down.
Also, cost of a new ring and pinion can be around $135 for a 1/2 ton axle, but not just anyone can change gears, b/c there are specialty tools needed to set the backlashing, and can cost around $300 to have professionally installed just for labor.

 

Yeah, I think reworking the ratios in my rear and front end have been on my to-do list for the longest time but I keep putting it off due to the fear of incorrectly setting the backlash tolerances and screwing up everything.
That, plus I want to put lockers on it but I don't know enough about lockers yet. (the gains and losses in installing them)

 

I'm with you on that one, I don't want to install gears myself, That is the one thing I'll let a professional do.
About lockers, the only loss you have is while in 4wd with a front locker it will be harder to turn. In the rear, depending on the locker, you might have some chirping if you power through a turn, but other than that, all you get is improved traction!
If you want to know a little more about lockers, just ask.

 

I'll Ask. I'm debating about lockers. I'm going to install 4.56 front/rear and figure I may as well invest in lockers since I have to change the carriers anyway. Question is: do I go Detroit or Air? I have limited funds and plan to do the rear in the next mouth and the front soon after but before fall.

I do realize 4x4 is unavailable until both are done.

Primary uses:
1) Pulling my boat through mountain road.
2) Moderate off-roading in the mountains (it is my daily ride)
3) Running in snow in the Sierra's.

Rig:
1991 351W E4OD
Lift: 6"
Tires: 35
Rear: 8.8 3.55
Front: D44

 

I would love to change them to 4.10s or even 4.56s but for a daily driver it is to expensive for me and puts extra wear and tear on the engine than I need. We're considerin' 4.10s front and back (of course) in my parent's ram.

 

nv_brewer, for the rear I would go with a detrioit locker. As long as you don't power through a turn you will not have any wheel chirp. For the front since it is your daily driver, a aussie locker(or lock right) would be a good cheap effective way to lock the front. But if you will travle on ice roads a ARB might be the better route if you have the money.