Some help with gear pattern?

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Freezerman

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8.75 rear, 3.55 in supposed "good" chunk. I pulled ring gear to bolt in suregrip. Set back lash at .007 where it was. Runs very noisy on the gas at all and slowing down, quiet just off throttle. Not sure what to make of this pattern. Thanks.

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Which case is this, 489,742? It looks and sounds like you better recheck pinion bearing and depth to start
 
Sorry, it's a 741. That's the thing. I never had the pinion out, only the ring gear. The pattern doesn't match anything I've seen so I'm not sure where to go with it.
 
Was it quiet before ? Did you run this gear before or did you just get it ?
 
Bought the pumpkin used with 3.55 gears in it, never ran it. Pulled the ring gear and put in sure grip, set backlash to what is before i took it apart. Ran it and noisy as hell.
 
Bought the pumpkin used with 3.55 gears in it, never ran it. Pulled the ring gear and put in sure grip, set backlash to what is before i took it apart. Ran it and noisy as hell.
At least you don't have to worry about ruining a crush collar, definitely pull the carrier back out and recheck for roughness, play and pinion depth to start or you are looking for disaster
 
before you take it apart increase the backlash to about .014 and see what pattern you have.
 
According to this chart backlash is to tight
 

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Great! Thanks for that chart, very helpful. I will try increasing backlash and see how it looks.
 
I would look for numbers on the back of the pinion to measure pinion depth, and get some real gear marking compound
 
I would look for numbers on the back of the pinion to measure pinion depth, and get some real gear marking compound
I use cadmium yellow artist paint, and thin it with motor oil. You don't need to use so much paint, a little goes a long way.
FWIW, It looks to me like pinion depth is wrong. But it looks so far off, it's kinda hard to tell.
 
Well with root toe on the drive side and top toe on the coast side it doesn't really match any of the choices. Maybe this gearset is bad? Also the outer pinion bearing just slides right on. Including I tried a new bearing. That doesn't seem right?
 
only the big pinion cone is pressed on. Did you make sure there were no burrs on the diff and on the face of the ring gear? You are supposed to use a carborundum stone on the mating faces. Have you looked at a FSM?
 
It's difficult to tell with how much you got globbed on there. Geeze, all you need is an imprint. It does look like you have a ways to go. Clean it up and try it again with a lot less.
 
when you check the pattern, you're supposed to use a pry bar on the diff to "load the mesh" by prying the ring gear away from pinion mesh to simulate actual running mesh conditions. Basically, you are maximizing the backlash with the prybar. It's all in the FSM.
 
the outer pinion bearing is not pressed on, and not the problem. any depth numbers on the pinion??
 
You have to make sure the ring gear is sitting flat, the caps went on correctly, and the carrier bearings are preloaded correctly. the left cap gets torqued first, and I like to leave the backlash loose, then use the LH adjuster to bring the carrier in to spec. Then tighten the RH cap adjuster to tighten up the bearings. You don't want to just loosen the adjusters. Always bring them tighter into spec and preload.
 
Ok. Ill try to get better marking. I hadn't planned on messing with the pinion at all. I bought the center unit used. Just pulled the ring gear to add the suregrip, apparently it wasn't good when I got it.
 
There was some numbers on the pinion shaft, or do you mean under the inner pinion bearing? There is 2 shims under the outer bearing they measure just over .040
 
He means etched into the head of the pinion. It being an oem gear set no center line measurement will etched into the head. I would widen the backlash to at least .010 (at the tightest spot) and recheck.

Who knows what it has been through before you bought it. Could have just been thrown into that housing. Could have had a problem before and they just pieced it back together to sale. I would also look to see if on the side of the ring gear has a 3 digit # stamped into it and the same # is found on the pinion. It could be on the head or on the side of the shaft, this is to make sure it's matched set.
 
That's looks so far off. I learned some lessons last winter!

Case is 741 per your earlier post!

What center? Open or 4 spider Dana, or do you have what I did and have a cone center in a 742 case, in your case a 741?

This makes a real real difference! Are you getting contact from pinion to center section when you try to get the backlash set? Listen to recommendations about marking grease and the amount applied! Good folks here got me on the right track and ended up having to shave the pinion head to get it right when I had mismatched components! Stop and be sure!
 
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If the chuck was just a used open deal, there's nothign wrong with the pinion - right up until you take it out of the case. Then you are into the "rebnuild it all" deal. I would re-do the carrier a few times first and see how it goes. I've done what you're doing many times - you don't cause problems unless the ring gear and carrier do not go exactly back where they were.
 
Looks like I need to order a rebuild kit. Read the FSM about 3 times and give it a shot
 
Looks like I need to order a rebuild kit. Read the FSM about 3 times and give it a shot

Do you know what all pieces you have?

741 Case yes!
What center sure grip? Dana 4 spider is easy to tell with + cross shafts and 4 small spiders. The cone style center has springs with thrust plates. The 741/742 cases were designed to use the Dana. 489 cases will accept both usually with no issues. My 742 with 4.56 was no issue with the cone style, but dropping to 3.55 caused an issue. So post back what you think you have or take some better pics from angles to help the forum help you!
 
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