DIY Diff Gear Swap (1 Viewer)

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Joined
Jan 19, 2016
Threads
8
Messages
41
Location
Las Cruces, NM
I want to remove my 4:10 gears in both axles and put in 5:29 gears. My local 4x4 mechanic was a jerk and refused to help me because I was "too young" to be an off-road enthusiast. I will be doing the gears and bearings, shims, gaskets, etc... Question is: is this a job I can do myself? If so can someone point me to a good website to order parts and talk to tech guys? I've been looking at LC Engineering, Trail Gear, and Low-range Off-road. I have plenty of tools but not many specialized tools (steel press, welder, and things alike). I'm farily mechanically inclined and can read directions well enough to get a job a done right. Is this a task I can do? Or should I be seeking help from a friendlier 4x4 mechanic? Thanks!
 
So remove the 8" differential carrier pull out the 4.10's and install the 5.29's into the same carrier the 4.10's were?
 
My local 4x4 mechanic was a jerk and refused to help me because I was "too young" to be an off-road enthusiast.

Is this mechanic a professional mechanic or just a local guy working out of his home garage - and define “refused to help.”

If it’s a professional mechanic, I wouldn’t expect him to “help” you do the job. He’s in business, not doing charity work. If he’s a local guy, do you have any prior relationship with him or is it just some guy you’ve heard of? Again, there are a few people I’d “help” with their project but I’m not going to open up my personal shop to just anyone.

Mudder has posted some good links that should give you the basics. Although it isn’t rocket surgery, it still helps to have someone who has done it before on hand to walk you through it the first time. You can learn on your own, but expect to spend some extra time with it. You’re likely going to spend more time on getting the pattern right and messing with the pinion freeplay than if you have someone who has done it before helping you.
 
Is this mechanic a professional mechanic or just a local guy working out of his home garage - and define “refused to help.”

If it’s a professional mechanic, I wouldn’t expect him to “help” you do the job. He’s in business, not doing charity work. If he’s a local guy, do you have any prior relationship with him or is it just some guy you’ve heard of? Again, there are a few people I’d “help” with their project but I’m not going to open up my personal shop to just anyone.

Mudder has posted some good links that should give you the basics. Although it isn’t rocket surgery, it still helps to have someone who has done it before on hand to walk you through it the first time. You can learn on your own, but expect to spend some extra time with it. You’re likely going to spend more time on getting the pattern right and messing with the pinion freeplay than if you have someone who has done it before helping you.
He is a long time local 4x4 mechanic. I was asking him which parts I'd be looking at buying and how much he'd charge for labor. Long story short he said that I was too young and that this is a hobby out of my price range meant for older people with more respect for the hobby. He said he wouldnt give me advice or work on my truck.
 
Long story short he said that I was too young and that this is a hobby out of my price range meant for older people with more respect for the hobby. He said he wouldnt give me advice or work on my truck.

So don't do business with him. If he doesn't want your money, give it to somebody else.
 
So don't do business with him. If he doesn't want your money, give it to somebody else.
That was the plan but I really want to start learning how to do my own work, I just don't want to dive into a project that I may not be ready for. So I'm still on the fence of what to do.
 
I personally don't set up diffs because of the the margin of error you have to play with is small. I fix everything else though.
 
I personally don't set up diffs because of the the margin of error you have to play with is small. I fix everything else though.
That has been my strategy too. I am more than glad to pull the diff, drop it off into the hands of a capable specialist, then reinstall it. Diffs are a critical component of the drive train and I really don't want to get stuck someplace.
 
Pull the third member (easy) and drop it off, along with your new parts to a shop that regularly rebuilds diffs. As other's have mentioned, a diff isn't something you want to experiment with if you're unfamiliar with working on them.

Sure, you might be able to set it up yourself, but you'll never know if it's really right or not.

I leave the diffs and head work (and block) to the pros. Everything else I'm fine with doing myself.
 
I've done several gear setups now. It all started back in 2002 when I wanted to regear my FJ62, but the prices to have it done (plus shipping the diffs to a shop I trusted) were insane, and I'm a cheap bastid. So, I figured I would do a low-cost swap and see if I could do it. I found a cheap used set of 4 cyl 4.88s, and installed them in a 4 cyl diff in my '84 truck. Drove it for awhile, they didn't burn up or make any noise, so I was encouraged enough to go in all the way. Bought a 20T HF press, a bearing splitter, the Park TW-1, and made all the spanners. Installed ARBs and 4.88s in both Cruiser diffs, worked out well. I've also done both e-lockers in my current truck, that was almost 100K ago.

The only tool that I don't have is that pinion bearing puller thingy, you can do it with the splitter in a press. A press is pretty much mandatory.

The FSM has a very detailed procedure, and if you buy Yukon gears they also come with a good set of instructions. Take your time, be patient. Take notes if every diff you do for future reference on shims and settings. You can do it. Screw that a******. When you get it done, drive by and make sure he knows you did it.
 
I agree with both sides in this case...A R&P is a very critical component that needs to be done correctly, But you have to start somewhere. Do as much reading as possible until you actually understand the process and are not just reading words and decimal points. TAKE YOUR SWEET TIME! The first diff. I set up, I redid the entire process a couple times just for peace of mind. If you have a clean, quiet area and go slow, you'll realize it's quite simple. Much easier then a Dana axle!! Oh, don't use a crush sleeve.. Solid spacers only!
 
I've done several gear setups now. It all started back in 2002 when I wanted to regear my FJ62, but the prices to have it done (plus shipping the diffs to a shop I trusted) were insane, and I'm a cheap bastid. So, I figured I would do a low-cost swap and see if I could do it. I found a cheap used set of 4 cyl 4.88s, and installed them in a 4 cyl diff in my '84 truck. Drove it for awhile, they didn't burn up or make any noise, so I was encouraged enough to go in all the way. Bought a 20T HF press, a bearing splitter, the Park TW-1, and made all the spanners. Installed ARBs and 4.88s in both Cruiser diffs, worked out well. I've also done both e-lockers in my current truck, that was almost 100K ago.

The only tool that I don't have is that pinion bearing puller thingy, you can do it with the splitter in a press. A press is pretty much mandatory.

The FSM has a very detailed procedure, and if you buy Yukon gears they also come with a good set of instructions. Take your time, be patient. Take notes if every diff you do for future reference on shims and settings. You can do it. Screw that a******. When you get it done, drive by and make sure he knows you did it.
Hopefully I don't mess up anything too bad then! If I get to a point that I dont feel comfortable working on it then i'll just take the assembled third member to another mechanic and have them put it together and ill reinstall it on my own.
 
i am thinking about doing this swap too.... i looked into Zuk, seems like a great guy and Im sure he does a great job! but, he quoted me $1275 for the swap. There is no way I can justify spending that. I think this is a job most people can learn how to do, if they have the tools and take the time to research and lean how to do the procedure. I think there is a misconception that only the pros can do gears and if you mess up by even .00001 the entire truck will explode! I say go for it! Take your time do it right! Post your progress on here and that will give some inspiration to other people like us. And then if your truck does blow up then we all will know what not to do! haha
 
Price good quality gears, master install kit, solid spacer, pinion seal now multiply 2x, now buy a press and a large vice, dial indicator, inch pound non clicker type torque wrench.
$1200 dosent sound so bad now.
Now you say I understand the theory behind this. I got this. Great I do too. But understand what you see on the gears when you check the pattern is its own science.
Now flip a coin to see if you missed somthing. This could cost more money to do again.

Unless you plan to do this often I would strongly recomend paying somone.

If you need to save $ consider reusing the bearings and skipping the install kit.
 
You can get a fully assembled open diff from Marlin for $769.
 
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