Rear axle swap question

[ymelnic1]

Hey guys. I'm replacing my rear driver side axle rod as this wheel had a wobble in it since I bought it. I decided to drain the fluid from the 9" and replace all seals while I was at it. I took out the passenger rear axle rod as well so I could remove the third member and drain the fluid. All went well and I filled it back with oil. When I swapped out the rear seal for the passenger side axle and put the axle rod back in, the axle does not seem to fully engage the differential. I can spin the axle and it does "touch" the rear drive shaft, but I can still spin the rod without fully engaging. Is something up with the gears on the inside of the third member? Did I mess something up?

Thanks in advance!

 

[Apogee]

Hard to guess with the information provided...what do you mean when you say that you can spin the axle and it, "..."touches" the rear driveshaft"? Is this an open differential or a limited slip unit?

 

[ymelnic1]

Sorry I probably just ranted. It seems like there is some engagement from the "teeth" on the shaft with the gears in the housing. But once I spin the shaft, I can see the drive shaft rotate some but then stops spinning while I'm continuing to spin the axle rod, almost like it's not in far enough in and is slipping. I'm really not sure on if its open or limited slip. It's a stock '74

 

[Okie69]

Do you have the other shaft in? It sounds like you may just be spinning the other side. If it’s an open diff.

 

[ymelnic1]

Yep the other shaft is in. I was thinking it could be worn shaft, but it looks just fine…

 

[blubuckaroo]

The axle splines on a Ford limited slip have a short section at the end of the driver side axle spline that drives the whole rear end. sometimes that 1/4" section of spline gets clocked out of position when reassembling. My advice is to have someone rotate the passenger side axle while you insert the driver side axle.
It's a really bad design that usually ends up with that first 1/4" of spline stripped off at the worst time. When that happens, the car won't move. You're better off with an open rear axle than this junk.

 

[ymelnic1]

Thanks blubuckaroo! I don't think the driver's side rod was all the way in when I was fiddling with it. Looks like a $1600 part is averted!