Pinion nut problem on Ford 10.25 rear Differential.
#1
08-04-2015, 04:13 PM
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Pinion nut problem on Ford 10.25 rear Differential.
- 1989 F series with the Ford 10.25 rear differential
I'm replacing the pinion seal on the 10.25 differential, and the pinion nut isn't going back on correctly.
Before removing the pinion nut, I counted the threads very carefully, and marked the nut and the pinion shaft with a cold chisel.
I've been working with the parking brakes set the whole time.
Now, the nut is tightened up and there is still 2/3 of a turn left to go. I've even put a breaker bar on the nut and it's extremely hard to turn it. The nut is F*cking tight, but still 2/3 of a turn less than where it was before I took it off. It probably has 150 lbs of torque on it already.
Also ... the nut didn't feel smooth when it snugged up. Kind of like "blip, blip" ... hard, then easy, then harder, then easy again (but not as easy as before) while I tightened it ... kept getting more difficult to turn until I couldn't get it any tighter at all.
One thought while I'm writing this ... I haven't released the parking brake and spun the pinion shaft to help the pinion bearings reset ... could that be it? I don't think so because I didn't pull the bearings or anything. They didn't really move while replacing the pinion seal. Maybe tapping the new seal in jolted the bearings loose?
If necessary, I can use the torque wrench method to tighten the nut, but I was hoping to just put it back together exactly as it was before removing it.
My hands are clean right now, and my wife is getting lunch ready, so I'll wait a while before going out again to work on it. Hopefully spinning the shaft will do it.
But if anyone has experienced this problem, and knows something about it, please help a brother out. Any help would be much appreciated!
Thanks.
I'm replacing the pinion seal on the 10.25 differential, and the pinion nut isn't going back on correctly.
Before removing the pinion nut, I counted the threads very carefully, and marked the nut and the pinion shaft with a cold chisel.
I've been working with the parking brakes set the whole time.
Now, the nut is tightened up and there is still 2/3 of a turn left to go. I've even put a breaker bar on the nut and it's extremely hard to turn it. The nut is F*cking tight, but still 2/3 of a turn less than where it was before I took it off. It probably has 150 lbs of torque on it already.
Also ... the nut didn't feel smooth when it snugged up. Kind of like "blip, blip" ... hard, then easy, then harder, then easy again (but not as easy as before) while I tightened it ... kept getting more difficult to turn until I couldn't get it any tighter at all.
One thought while I'm writing this ... I haven't released the parking brake and spun the pinion shaft to help the pinion bearings reset ... could that be it? I don't think so because I didn't pull the bearings or anything. They didn't really move while replacing the pinion seal. Maybe tapping the new seal in jolted the bearings loose?
If necessary, I can use the torque wrench method to tighten the nut, but I was hoping to just put it back together exactly as it was before removing it.
My hands are clean right now, and my wife is getting lunch ready, so I'll wait a while before going out again to work on it. Hopefully spinning the shaft will do it.
But if anyone has experienced this problem, and knows something about it, please help a brother out. Any help would be much appreciated!
Thanks.
#2
08-04-2015, 05:30 PM
Counting threads & marking the nut won't get it where it needs to be; only where it WAS (which wasn't necessarily correct for its level of wear). Use one of the official published procedures for setting pinion preload if you want the gears to last. You might be able to find those procedures through these links:
http://www.fordracingparts.com/downl...And-Pinion.pdf
http://www.revbase.com/BBBMotor/
http://www.ringpinion.com/
http://www.differentials.com/
As to why it's not going back all the way...
Probably because some dirt got onto the seating surface, but possibly because you allowed the oil slinger to fall out of place. You didn't specify which version of 10.25" you have, or even what truck it's in, but it's probably one of these:
. 
Read this caption:
http://www.fordracingparts.com/downl...And-Pinion.pdf
http://www.revbase.com/BBBMotor/
http://www.ringpinion.com/
http://www.differentials.com/
As to why it's not going back all the way...
Probably because some dirt got onto the seating surface, but possibly because you allowed the oil slinger to fall out of place. You didn't specify which version of 10.25" you have, or even what truck it's in, but it's probably one of these:
. Read this caption: