741 pinion nut torque too tight- did i damage it

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lee g

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Needed to change the pinion yoke since one of the u joint strap bolts broke. Put a new one on and tightened it some with my electric torque wrench. Well I guess it tightened the nut way more than I realized. Threw the torque wrench on there and I over tightened it. Took the pinion yoke nut back off and started over. Now to get to just 200 # on the torque wrench the pinion will not turn. I thought the torque value on the nut was 240# and my electric torque wrench only puts up 300#. Any thought other than I shouldn't have put the electric torque wrench on it.
 
try this --- back the nut off and hand torque to 50 lbs/ft , then turn the yoke several revolutions back and forth ---now tighten the nut to 100 lbs/ft and again turn the yoke ,, then to 150 lbs ft turn the yoke again then tighten to final torque --- if it doesn't turn at 50 lbs/ft or 100 lbs/ft -- stop there --- you will probably have to reset the pinion bearing preload shim pack thickness if you have a 741 or 742 case -- if it is a 489 case a new crush collar will have to be installed or if you can get the front bearing out drop a .010 shim on top of the crush collar ,, reinstall the bearing ,,, seal ,,, and yoke ,,, retorque to the proper pinion bearing preload --- 20-25 in/lbs new bearings -- 8-15 in/lbs used bearings
 
Yep, I will be taking it apart. 50# on the torque wrench and yep its too tight.
 
New bearings can you explain why old Kimmer. Trying to learn. Never fooled with rear chunk/pumpkin
 
The bearings get worn and will seat deeper into the cones thus having less clearance. Or did the front bearing come out and a shim fall out. 1 other thing to check is to see if the dust cover on the yoke interferes with the housino. Kim
 
Did you hold the yoke while tightening the nut or did you hold against the gears?
Either a bearing is bad or you need to reset the pinion preload.
 
Held the yoke because the pumpkin is still in the rear end.. The bearing didn't come out.
 
It has been years since I worked on a 741, but I think the pinion bearing preload is adjusted with shims. A shim could have stuck to the old yoke, and when you installed the new yoke, you tightened the preload too much. It has happened to me on gear setup before. I don't think your electric impact overtightened the pinion nut.
 
It has been years since I worked on a 741, but I think the pinion bearing preload is adjusted with shims. A shim could have stuck to the old yoke, and when you installed the new yoke, you tightened the preload too much. It has happened to me on gear setup before. I don't think your electric impact overtightened the pinion nut.

The shim is behind the bearing on the front of the pinion . No way removing the yoke would pull a shim out. But pulling the front bearing could.
 
If the rear was run with a loose pinion nut, the preload shims get polished by the slowly spinning front bearing over time. This causes excessive preload when you tighten the nut.
 
Pinion nut was tight prior to removal. Used an impact to remove it. Yes, it tightens now till the dust shield touches.
 
I once built an engine using a new replacement balancer . When I started it the oil slinger rattled like crazy ! Turned out the new balancer snout was machined a tad short and would not seat the slinger up against the step in the crank .
Its possible the snout on the new yoke is a bit longer than the original .
 
I once built an engine using a new replacement balancer . When I started it the oil slinger rattled like crazy ! Turned out the new balancer snout was machined a tad short and would not seat the slinger up against the step in the crank .
Its possible the snout on the new yoke is a bit longer than the original .

^^^^ I would say the snout on the new yoke is actually shorter than the original one causing the new yoke dust shield to contact the case before the snout is seated to the front bearing.

Good point mbaird.
 
No it’s not shorter if it’s a factory yoke. He needs to change the dust shield from the other yoke. Or run without as Roy says. Kim
help me visualize how the dust shield comes into play here ? unless it was bent .
 
I’m guessing he got a yoke from a 489 case. The dust shield is bigger around so the curved lip to hits on the front flat where the pinion snubber bolts on cause the case is smaller. It’s kinda like putting too big of a lid on a pot or fry pan but it won’t sit level cause it’s hitting the handle. Kim
 
I have several yokes with various flanges but never knew which ones belonged to which cases.
 
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