questions setting up my 742 (again)

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mean318

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Hey everyone, I have taken out my 742 4.11's out of the car again because of all the noise it was making. I narrowed it down to the pinion having end play, which all I could think of is that the bearing races were not in all the way. I have now beat on the races and visually inspected that they are all the way in. The problem I am having is that I have no bearing pre-load unless I put in a pretty think shim in between the gear and bearing which in turn would change the pinion depth. I have no shims on the yoke side because after reading the mopar muscle tech article on 8 3/4's it says to loosen bearing pre-load you add shims to the yoke side of the shaft. So what should I do?! Do I set the pre load first and then go to pinion depth? What I saw before I took it all apart the first time was that the gear pattern was "walking" I am thinking that was from the loose pinion bearing. So ladies and gentlemen what should I do? I realize I have probably answered my own questions and I would just like some input on this Thank you very much for your time and knowledge!

Sorry for the ranting
 
The instructions that came with my Richmond gears are pretty general in nature, but the say to set the depth first, then set the rotating torque or preload. As I remember, there are shims behind the bearing to set depth, and then shims behind the yoke to set preload? I have slept a few times since I built the third member so I could be way off. I know that I made a set of "checking" bearings out of an old set so I wouldn't have to press the new ones on/off a bunch of times.
 
thanks, I have a set of checking bearings that I am using for the pinion.
Now this is making more sense to set the depth first. I just ran a pattern and the pinion is too deep on the ring gear, So that means I would have to take shim out to get the pinion back right? Well I did that and now I have no pre load whatsoever even though I have no shims on the yoke side. When I do get my pinion depth right with no shims on the yoke side then how do I get my pre load right?
 
What size shim do you have between the pinion and the large bearing? I start with .020 and then install the pinion in the case with no preset shims until it is snug. then check your pattern. From there make large adjustments, like .005 adding and taking away until you get a good mesh pattern. Once that is done then add your new bearing on the pinion ad set the pinion preload with the small shims behind the smaller bearing. Sounds like to me that you don't have shims behind the larger bearing?
 
the funny thing is is that I have shims in between the pinion gear and bearing I tried a .060 shim first and of course it was too deep on the ring gear, then I went to .045 and still too deep. Then I went to .032 and with no shims for pre-load and a fully torqued down pinion nut I had no pre load whatsoever. When I go with a smaller shim than .030 I get end play in the pinion.
 
Can you post a picture of the pinion. What is the part number on the large pinion bearing and race.
 
The 742 case should start with an .090 shim. You shouldn't have to stray too far from this, like .004 to .008 either way. If you can't get a decent pattern with that then you have a bad gear set, probably from being run with play in it.

You must set the pinion depth first, there is no other way to do it.

BTW bearings can be different from set to set, so your "checking" bearings may not be as close as you think to the ones you use.

Oh yeah, one more thing, the shim should go under the head of the pinion gear with the bearing on top of it. Your first mistake was starting with a shim that was way too thin. If you get too far out the pattern will never look right. Start with an .090.
 
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