For those of you who have knowledge of Ford 9" differentials................HELP! I am in a quandary here. Some history: I ordered a new 9" non-posi, 31 spline differential with 3.0 ratio (the old one was heading south.....quickly). Out of the box, turning the yoke required some effort (new gears, alignment to tight, no oil ?) I assumed this was probably pretty normal (the assumption may be my downfall) I removed the old, installed the new, slid the axles in and buttoned up the flange nuts (not too tight either) and tried turning each axle while car was off the ground. Took a lot of effort. They did not exactly spin freely (see above assumption). Filled the rear end with required amount of oil, let the car down and O-crap! While backing out of my driveway (turning left) the left axle locked. Well.......... I pulled back into the garage, jacked up the left side, released parking brake and shifted to neutral. Axle would not budge. I loosened the flange bolts all the way out and tugged on the axle, (I could have removed it then if I had wanted) still no movement!? Wheel bearings are in good shape (rollers) and were replaced recently. Any clues, ideas? My own conclusions is that the spyders are not right and causing one helluva a bind. I have not mentioned the Vendor, since they have not had a chance to respond yet. BTW.......the rear end is out of a 1975 F-100. Any suggestions are GREATLY appreciated.
The bearings in a rearend center section are set up with preload, so they should be a little hard to turn by hand. Just to be clear, this is a deal where you are only replacing the center section, and it was OK before? I'm wondering if the housing is misaligned somehow. When you pull it apart, see if you can turn the side gears easily by hand. If it's an open (non track lock) differential, you should be able to spin them around easily.
Thanks for the reply Jim. Yes I am only replacing the center section, it is standard open carrier, and it was OK before. I dread doing this again............but I really have no choice. A royal PITA
The unit you replaced was a rebuilt 3rd member, correct? My thought is the back lash is set to tight. If you have the unit out and on the bench, you should be able to hold the pinion in one hand tight and wiggle the ring gear back and forth. This will be a very small amount of movement and I believe the normal back lash is .008 - .010. If the back lash is too tight, the effect is like forcing the ring gear into the pinion gear and that will make it very hard to turn. The pinion bearings are set up with preload as Jim mentioned. They are normally around 25 inch pounds with a new bearing. Did the axle shafts slide in with ease? I would not suspect any housing or axle problems if the axle shafts installed easy. You should never have to pound these in with a hammer. They will be a little tight when the bearing begins to enter the tube and the splined end into the spider gears but not bad. As far as what is too tight. You should be able to grab the pinion yoke and turn it with a very small amount of resistance with one hand. Sounds to me liker you need to contact the vendor and have them send a replacement. Make sure they cover the shipping on the return. Hope this helps. Tom
Tom, Thanks for input. Yes rebuilt unit. The axles went in just fine, I actually put a little gear oil on each axle end to alleviate any hard pushing, and shoving. I would certainly not use a hammer. Turning the yoke is where I became concerned that the setup was way to tight. My bad..........should have stopped right then. I'm with you on this one. I sent them a message yesterday after the (ugh) 15 foot move. I haven't pulled it back out as yet..........appears that my fourth will be other fireworks.
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