Doing 4:10 to 3:73 Gear Swap on 4X4

[CrewCabDiesel]

ok axle experts, need some advice,
After talking to a number of shops to pay to have gear ration changed and what how they did it I am not impressed and I believe I can do better.
So what tools do I really need and any short cuts?
I have both front and rear complete axles that I am pulling the gears from but don't want to use those axle housings, rear has a twisted tube and the front housing is just loaded with rust. So in the end I will have a ton of extra parts.
So please chime in.
Thanks
Kyle

 

[Motorhead]

I personally think that just the right tools might NOT be enough. I am in NO way saying you couldn't do it but experience WITH the right tools is how I would want the job done. I have done automotive work and repair for 45 years but differential gear set up and automatic transmissions, I leave to the guys that know them.

 

[Hoefler]

You will need a dial indicator with a bearing pullers, magnetic base, micrometer/calipers, and a torque wrench along with the necessary common hand tools. Setting up bearing pre-load, pinion depth and ring gear backlash are crucial to the longevity of the gear set. It is not for the shade tree mechanic to do for the first time with out supervision from a experienced gear man.

 

[NIsaacs]

You will need a dial indicator with a bearing pullers, magnetic base, micrometer/calipers, and a torque wrench along with the necessary common hand tools. Setting up bearing pre-load, pinion depth and ring gear backlash are crucial to the longevity of the gear set. It is not for the shade tree mechanic to do for the first time with out supervision from a experienced gear man.

I agree. The pinion depth is critical on a used gear set. The pattern needs to be set exactly how it was set originally, even if that pattern was not exactly right the first time.

Nick

 

[sag2]

To do it correctly so the parts will last you need the pinion depth gauges for both axles. The cost to buy them will far exceed the cost to have the gear sets installed. The shade tree way is to use all the shims from the new ones, but that will most likely result in lots of noise and short gear life.
Unless you have the tools let a good shop do the set up. Also setting up used gears in another housing may still result in noise and wear.

 

[S.Morris]

You have the worst case scenario because you are using gears from another housing so that the shims from either housing will most probably not be right or even close.

Gear set up is either right or it's wrong with very little wiggle room. You will have to replicate the backlash and pinion depth on the used gear set you are transferring or as has been said you will get a noisy gear set.

It can be done but in this case , it is more complicated than just bearing replacement in the same housing and you will need an experienced gearman that is also very familiar with your brand of housings.

 

[BillDriscoll]

sure you've heard.....Pay me now or pay me later.....
anyway, I'd like a report on cost because I have the 4.10's and dont really tow anymore

 

[CrewCabDiesel]

Thanks for the replies guys and keep them coming.
I wish there was a good axle company close, but there isn't. I spent tons of time on the phone (more than I did getting a total knee replacement according to my wife) and in some cases stopped at the shops which was a big disappointment. I would rather do it myself, than letting these so called professionals work on my truck. For the last 10 years since I have moved down here I have seen more shade tree work done by shops in the upstate than anyplace I have lived in the USA. This comes from dealing with shops delivering parts part time and hearing (and seeing the results) about the disasters caused by repair chains, dealerships and local shops that I would not let any of them change my wipers. It is so bad around here trying to find a good mechanic that I have people drive and hour to have us fix their Dodge trucks.
So with that said, my plan if checks out, I am going to transfer all components from one axle to the other including bearing and races IF they are still good (this is what most of these shops were going to do). After inspection, install those parts in my old housing. I have been reading and watching videos on the process and I think I can do it. I have coming the Miller 8883A adjustment tool, pinion yoke spanner wrench, inch pound torque beam style wrench, and gear compound. I have a 20 ton press, bearing splitter, 2 dial indicators, one magnet base and a huge set of tools. I plan to measure pinion depth and ring gear position of both axles before I start (making a tool for this).
My skill set, Work in a garage from 12 years old to 18, move up to helicopter powertrain repair and NDI specialist, top that off with 24 years of owning a computer and cash register repair shop in West Michigan, now a high school social studies teacher and coach.
So anyone that wants to come on by that knows these axles I will be glad to pay you, otherwise I am dependent on my TDR brethren for help, so please let me know what else I need to do.
Thanks
Kyle

 

[S.Morris]

Sounds like you are getting all squared away for the job. I will make a suggestion for pinion setup.
Use one of the sets of pinion bearings (that won't be used in final assembly) and hone the inside out with a flapper wheel so that the bearing is a slip fit on and off. This way changing shims for pinion depth will not require pulling bottom bearing off every time. .. You can thank me later:-laf

Also when you mark the gears with lead use one hand to load the pinion flange while you turn the ring gear.
Also when setting your backlash check runout of the ring gear and take that into account and err on the side of too loose rather than too tight. eg. The ring gear will have say .002 runout. IF you are setting at say .008 backlash this will mean your backlash will vary between .006 and .010 as the ring gear turns.

Take these measurements on the set you are going to be using before you disassemble it. Sometimes in used sets you can get high spot on carrier itself without ring gear and rotate ring gear bolt down position to get a more true runout if needed. Hope this makes sense....