I recently purchaed a rebuilt differential with all new parts. To my dismay I received the diff with the wrong sized pinion yoke. My options were to send the thing back and wait around for them to swap the yoke, or just use the one off my old one. I opted to use the old one. I found no damage, cleaned it up and painted it. I removed the wrong sized yoke from the new diff and slipped my old one on with the washer and nut. I tried to find information on the torque of this "pinion nut" and I only came up with pinion bearing preload. This kind of scares me. All I need to do is swap the driveline yoke for my old one and retorque the nut. I did find an old post on another forum that recommended 150ft pounds. I currently have the nut torqued to 150ft pounds. Is this going to work or did I just ruin new pieces in my differential by messing up preset bearing preload from the manufacturer?

 

If the yoke turns freely with only a little drag, I tthink you'll be ok.

 

I installed the new spline with just a tiny bit of mobil one synthetic grease to make the yoke slide on easy (very little grease). I lightly tapped on it with a flat board and hammer to ensure it was on all the way, then I installed the nut. It appears the company I ordered the rear end from uses a lock nut on the pinion so I didn't use the locktite. At the same time though, I never felt when or where the thing butted up to the crush sleeve on the inside. I did the torque in a slow careful process and hit it only once when the wrench clicked. Now that I think about it, I'm almost certain I didn't crush things on the inside as the nut was hard as hell to come off originally, even with my impact wrench. I think they might of had it tighter than 150ft lbs. My main concern was that I had it tight enough. It may just be me, but it almost feels like it turns easier from the half shafts than before. The thing is still brand new and hasn't had any oil put in yet.

Gary, do I check the rotation drag by setting my torque wrench to 18-20 INCH lbs then turn the yoke with the wrench on the nut and see if it clicks? Only way I could think to do this. - Oops, I don't think my wrench goes down this low :X

Also, #2? I assume that's a sealant for the splines. I noticed when I took the new one off it didn't have any sort of stuff on it. It was perfectly clean and black. I didn't use anything on the splines other than a little bit of grease to make the thing slide on the new shaft. I hope it will be ok because I don't want to jack with that nut anymore, hehe. If worse comes to worse, I'll be underneath the car installing some sealant and playing with the nut again.

 

My opinion, never trust a lock nut.

 

I don't agree! I made a good lifetime friendship with my friend Dan Amaral who now owns one the better machine shops in our area due to this same presumption. Dan wanted to end the pinion seal leak on his 1967 SS 350 Camaro. He changed the pinion seal and out we went for a "test drive". Things went well untill we were 10 miloes away from his house and we "banged second gear" on the old Muncie. The Camaro made a funny noise, locked the rear wheels up and slid to the side of the raod. After towing it back home and dropping the differential cover, we found a strange scroll mark arount the differential case. The pinion gear had backed into the differential case and locked it up. Luckillay for us, there was no major damage and we were able to polish the case and put everyting back toghether. The SECOND time around we consulted a Chevy Service Manual a old auto mechanic and made darn sure we had 18-22 in/lb of differential pre-load on our pinion before doing the second test drive. The Camaro ran for years with a mild 13 second 350 motor in it on our "first differential" rebuild. You can use a Pontiac "conversion" U-joint to go from the 1310 series Spicer to the 1330 series yoke of your differenttial (TH350 size to THM400 size U-joint.) I hope this helps you out.