Pinion shaft removal question

[K.ronic]

Ok.....I have a 3.08 rear end that I'm trying to swap gears in. When I took the shaft bolt out and it did break, but it broke in a way that let the shaft spin all the way around. I go to slide the shaft out and it gets, for lack of a better description, stuck. The 3.73 gear set I have the shaft slides out just by pushing on it with little to no resistance. I searched around for a bit and saw that lots of people were having problems with the bolt breaking off the wrong way to where you have to extract it, but as I said, this wasn't the issue for me. I could, with a punch and hammer, get the shaft out enough that I could hit it with a grinder and ground it down until I could get the broken part of the bolt out of the shaft just to make sure that wasn't the problem. Now when the shaft is centered in the housing the gears spin like their supposed to, but when I start trying to work the shaft out (with a punch and hammer) the gears completely bind up and won't turn at all. The shaft isn't binding up on the housing because I can jiggle the axles and see play between the shaft and the hole that it's trying to come out of so that tells me that it's getting "stuck" on the gear itself. What's weird about this is that, as I said before, when it's centered it can spin freely inside the gear. When I beat on it with the hammer and punch it gets to a point where it feels like it's hitting something solid like a c-clip or something. And no....I'm not beating on it where it's straight up and down, therefore, hitting the drive pinion.

This is driving me crazy. There, in my mind, is nothing that it could be hitting. When I work it out in either direction the ends of the shaft are making it past the races (?) on the back of the gear so it's not catching that. Is there a c-clip that I'm missing somewhere? Or is there possibly a tapered end on the shaft (I tried to remove the shaft in both directions with the same problem either way)? Is there a possibility that the shaft itself is bent just enough that I can't visibly see it, but enough to not let it come out of the gears? I haven't tried an air chisel on it yet, but if that doesn't work then what else can I do to get it out? I'm not worried about destroying the gears because I'm replacing them anyway (I just want the housing and the 5 lug axles), but I would prefer to not have to grind it completely in two. At this point, the only part I have destroyed is the shaft itself which I can replace.

Here are some pictures of what's happening....






Any help would be greatly appreciated!



P.S. How's that for a 2nd post, LOL?

[dwcsr]

Torch out the cross shaft inside in pict 3 and 4 at the side gear once you get that section out you can drive the remaining out and pull the axles.

[71 super]

Make sure the axles are slid to the outside position to be sure the pin is not hanging on the axle shafts. It sounds like there is a wear problem on the pin. try rotating your carrier to the point where the pin is at the 1:00 position and tap the pin down to the 7:00 position. As it releases rotate the carrier and use a pair of vise grips or cannel locks to finish pulling the pin out. From the picture you have your work cut out for you.

[LONGHAIR]

There is probably a burr on the shaft, from one or both of the spider gears, that is causing the binding....but this is the easy part of this job.

A ring and pinion swap is not a job for a first-timer. Having someone with experience is more than a great help, it's almost a necessity.
There is a lot of precision and patience required...."good enough" is NOT good enough. You will have the entire assembly apart and back together several times.
You will need a way to press the bearings on and off, plus a dial indicator to check the backlash. It is a combination of art and science. A lot of it is just repetitious movements, but the pattern still has to be right once all of the measuring says it should be. If not it still has to come apart to be adjusted again.
Experience can cut down on some of the moves.....but it's no guarantee.

[eagleuh1]

How do you ever do things yourself if there's never a first time? Read up, learn everything you can, ask questions when you got em and then git er done. Replace or repair if required.

[jerry moss]

Originally Posted by eagleuh1

How do you ever do things yourself if there's never a first time? Read up, learn everything you can, ask questions when you got em and then git er done. Replace or repair if required.

when building a differential it's best to have someone with considerable experience to help guide you through it, it's not for a novice. i've built several at work but still have our head mechanic double check my numbers and contact pattern. i got very lucky just yesterday, i built a diff in a 2000 1/2 ton 4x4 and for my initial install i used all the OEM shims and it came out exact on the first try- i put in everything new, carrier, ring and pinion and bearings. backlash was supposed to be 3-6 thousandths and i was at 5 thousandths on the first try with a perfect contact pattern. usually i end up pulling them apart a half dozen times or more.

[K.ronic]

Originally Posted by dwcsr

Torch out the cross shaft inside in pict 3 and 4 at the side gear once you get that section out you can drive the remaining out and pull the axles.

This looks like what will end up happening.....because nothing else is working.

I still don't exactly understand what's hanging it up. It's not a burr because, as I said, its spins freely when it's centered and I can drive it out about a 1/2 inch in one direction and a little over a 1/4 inch the other way before it stops moving. And when it stops it's rock friggin' solid. I broke one mini sledge by pounding on it. Is it common for the pinion shaft to be bent slightly? I'm really more trying to understand how this happened than how to fix it. Fixing it is the easy part (with the heat wrench anyway....), I'm just a "need to understand it" kind of person and want to understand it for future reference.

Also to the gentleman that suggested that I have some one that actually knows what there doing help me: I appreciate what you are trying to say, however, that is a luxury I do not have. I am, however, quite capable mechanically and after the modifications I'm doing to the housing are done and it's time to put all the new stuff back in I will have done my homework. But, until I get the gears out of the housing, putting a new ones back in is mostly irrelevant.

More to the point though, anyone is capable of anything as long as they have the three D's: desire, dedication, and drive. Everything that has ever been done had to be done the first time by some one that had never done it before. Please don't take this the wrong way because your advice is sound and I appreciate it, but I just don't like to discourage anyone from doing things for themselves.

[LONGHAIR]

We are just trying to save you the $$$ and headaches.....and, while I can appreciate the thinking that everything had a "first time".....not all of those "first times" were successful. See where we are coming from?
This is no easy task, and the money you have to invest into the tools that it takes to do it is wasted if you only ever do it that one time....and, if you destroy it, you are out the parts money too. Then, are you gonna trust your "second time"? Unfortunately, this is a job that "looks easy enough" because "there really aren't that many parts to it"
If you pay and expert, you get it done w/o any of the hassles and you get a warranty.

jerry moss, I have had that happen one time of the hundereds of differentials that I have had apart......one, and it's almost scarey?

[D.PASSMORE]

Good advice from all, I have the same issue, I have a SWB 4x4 with 3.08 front and rear and looking to put taller gears in it. Question I have, will the 3.73 gears fit on the 3.08 carrier? I thought there was a size difference.

[dwcsr]

Originally Posted by K.ronic

This looks like what will end up happening.....because nothing else is working.

.

I've had several like that over the years. Usually its wear and parts just don't line up any more. Or someone got in there before you and "repaired" it once and for all. The pin snapping and coming out trashing the rear is a common issue with the older 12 bolt rears.

Once you get the cross shaft section out you can pop the axles and remove the carrier. Get it on a bench and you will get a better idea of what the issue is. Normally I would'nt say cut the shaft but you indicated that you don't need the carrier and its most likely junk now anyway. I'm with you on finding out why it won't come out so post it if you do get the ends out.

[71 super]

The 3.73 gears will not fit the 3.08 carrier, the 3.08 is considred a "3" series carrier and the 3.73 is considered a "4" series carrier. The ring gear thickness is different between the carriers. You can buy a 3.73 gear set that will fit a "3" series carrier from richmond and others, but if dealing with stock gm components they will not interchange.