Just swapped a rear end from a 97 Trans am into my 87 Iroc. I got a great deal on it and was stoked until after install and low and behold a bent axle shaft. Got a replacement from the junkyard from a 98 camaro. I replaced the bearing and seal but am running into a problem putting the new axle in. It will go in and feel like it is splining, then suddenly stop about halfway through the spider gear and is able to spin even though it looks like it is splined. Seriously WTF! I just don't get it. If anyone can help me out on this please let me know. Call me retarded or whatever (I've been called much worse) but any help would be appreciated. Thanks.

 

The 97 and 98 should both be 28 spline axles. Sounds like the axle you picked up is only 26 spline. Did you pull it from the car/diff yourself? If not, the junkyard gave you the wrong axle. If you did, it's possible the 98 in the junkyard had a third gen diff under it.

Compare the replacement axle with the old one. Count the splines on each. Measure the length on each. I don't think there was a length change during the fourth gen run or if there was, it isn't enough to make a huge difference.

There's also the possibility that the "great deal" that you got on a 97 diff is actually a third gen diff which uses shorter axles and you're now trying to install a longer fourth gen axle.

 

I pulled the axle. They are both 28 spline and the same length.

 

Are the splines on the replacement axle damaged or twisted preventing you from fully installing it into the side gears? Since the left and right axles are the same length, try the axle in the other side.

Put some grease, vasoline or assembly lube on the splines and install it as far as it will go. Pull it back out to see how far up the splines it's going.

 

They look pretty good. I even tryed to put the old one back in just to see. It is doing the same thing. I looked down the tube and don't really see anything in there that would obstruct it. One person said there is some washers acting as shims next to the spider gear that could have fallen. I'm not sure about this as I've never taken apart a rear end. But it really looks like a straight shot. I also thought about trying it in the other side as well but my car is parked under a awning and their is a wooden devider that would keep the the shaft from coming all the way out. (Stupid base housing!) What is really making me scratch my head is the fact that they spline half way then stop. Then I can turn the the whole axle shaft freely. How is that even possible?

 

(I got a great deal on it and was stoked until after install and low and behold a bent axle shaft.) Don't feel too bad, I did the same thing once. The original junk yard, plus the junk yard i bought it from, and me didn't check for bent hubs. I had to replace both axle's also.

 

The spider gear thrust washers would have been my next suggestion.

 

So how would one go about moving them back in place with the rear installed? Is it possible? How did they come misaligned in the first place? I wish I could see an exploded diagram of a diff. That would make things so much easier.

 

The thrust washers can fall out of place when you pulled the center pin out to remove the c-clips. The thrust washers are behind the spider gears that are held in by the center pin.

 

Its the driver's side if that makes any difference. I Just don't see what is stopping it from going all the way in. And why is it able to spin when it looks like its splined. Am I going to be able to fix this without rebuilding the entire differential?

 

Pull the side gear out of the carrier and see if it slides all the way down the splines. It only needs to slide down far enough to install the c-clips then the axle is pulled back out and the center pin holds it all together.

Is the axle going in far enough to reach the bearing? Is the bearing surface of the axle the same size as the old axle? Is the bearing wrong? Can you slide the old, bent axles back in?

 

No the old axle will not go in as well. Are you talking about the wheel bearing? If so it is the correct size... I pulled the new one i installed back out and it slid all the way down the shaft to where it would ride installed. The shafts are going half way through the splines about an inch and a half from being able to install the c clips. After looking at the axle further. I see that after the splines the shaft bevels out a bit. I think this is the point that I am getting snagged on a thrust washer behind the side gear that has fallen down.

To remove the side gears will I need to remove the clutch pack first? (limited slip diff) If so how is that done? I really don't want to mess anything up. Or have to bring it to a shop. I've done everything on this car myself and i don't want to start shelling out money to shady New Orleans mechanics. Plus with a government shut down happens I might not be getting paid. LOL

 

Update. So found out what it was. Screwed up carrier assembly. Side gear mounting area (if that makes any sense) is out of round. Finally got it to slide in months ago. Making thunking noise on coast. Over time got worse and worse. So going 9" route. Too much torque going to that stock rear. Also TH400. Tired of breaking stuff.