Pinion bearing ?

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Coyote Jack

Coyote Jack

Member #55, I'm old
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Does anybody know how the pinion bearing in a 8 3/4 is put on? Is it pressed on or forced on when you tighten up the pinion nut? Can you get it off with a puller? If anybody has a tech paper they could share on assembling an 8 3/4 I would be most grateful.

Jack
 
which pinion bearing??
I had a new gearset and bearings, so the rear bearing (the one by the head) got pressed on, after i found proper pinion depth ( i bought an extra one and machined it out to have a snug but slip fit so i could disassemble and reassemble easily until I got the right pinion depth. the new bearings are so close in tolerances that when you put the actual press-fit bearing on, it will still have the same depth.
the front bearing (small one) is also a pretty tight fit, so I used the old front bearing to get a close shim pack (solid spacer) and then used the yoke and nut to get the new bearing on. the shim pack wasn't right with the new bearing, so I had to press the pinion back out to adjust the shim thickness. since I got a preliminary thickness with the old bearing, and added .003 to it for the first new bearing fit, I only had to press it out and back on once, so I could add another .001 to get the preload right

HOWEVER....a lot of people just use the crush sleeve so they don't have to worry about solid spacer shims....

(i did this with a 489 center section)
 
Jack the bearing is pressed on and no you can't get it off with a puller.
If the bearing has been on there a long time it's probably gonna have to be cut off!
When i had the bearings pressed for my Scamp the guy had to cut off the pinion and the carriage bearings as well.
 
FWIW, when I rebuilt the 8.25 last year the inner pinion bearing was pressed on and becomes trash when you press it off because there was no way to grab the race with a bearing puller. The outer bearing would slide on and off with just a little help.

BTW, there is usually two numbers scratched into the end of the pinion gear.

The one that is a number like 2.*** is the distance of the center line of the carrier bearings to the top of the pinion gear. If you have the tool to make this measurement then it's the exact position that the pinion needs to be in to ensure proper pinion depth (no multiple trys with a pattern check).

If the pinion is marked +006 (or a minus number) that is the distance in thousands from an ideal dimension. If the pinion you are removing also has these marks this will be the simplest way to get the correct set up.

Lets say the old pinion is marked +005 an the new one is +003, the difference is 002. So all you have to do is remove 0.002" worth of shim thickness from what was there on the old pinion for the new and you are done. If the old was -005 and the new was +006 then you would have to add 0.011" to what was there.
 
Here is the deal. I removed a set of 4.10 gears from a 489 case and I am selling them to Jack. The 489 unit was just rebuilt 200 miles ago before I bought it. So from what I read here it would be better to leave this bearing on to make Jack's job easier when he puts it in his carrier. This is the first time I have ever done a rear end before but from what I can tell I have a crush sleeve. So if I just leave this bearing on and get a new one when I order my new gear set all will be good?
 
That's what I am reading to. It seems that the important factor will be the shims or crush sleeve. I would still like to find some kind of tech article before I put this pig together.

Jack
 
Coyote Jack said:
That's what I am reading to. It seems that the important factor will be the shims or crush sleeve. I would still like to find some kind of tech article before I put this pig together.

Jack
Click to expand...

Hey Jack,

If you are going to use a 489 gear set, I'd highly recommend getting rid of the crush sleeve the factory used. I use the solid pinion spacer (availible from randy's or richmond) and set pinion bearing preload the way you'd normally setup a 741 or 742 casting.

Why do I say get rid of the crush sleeve? I've seen them come loose in racing applications, and some nasty carnage as a result of the pinion slamming the driveshaft forward, trashing the transmission/front pump.

If you need some pointers for setting it up, gimme a ring. HTH's

:afro:
 
Been there done that. The pinion makes a nasty noise when it moves in to the ring gear.
 
This thread has gone off course!!!! Right now all we need to know is If I should leave the Bearing on it for Jack to use or do I need that for putting new gearset back in?
 
leave it on, since it's practically new....BUT only as long as you supply him with the race that goes with it....get it out with a brass drift to prevent damage
 
Mopardude,
I saw that article, I am going to print it out and study it throughly.

Chris,
You may get a phone call from me, I had already figured getting rid of the crush sleeve. Now I have to get to the point where I am comfortable getting into this.

Jack
 
Coyote Jack said:
Mopardude,
I saw that article, I am going to print it out and study it throughly.

Chris,
You may get a phone call from me, I had already figured getting rid of the crush sleeve. Now I have to get to the point where I am comfortable getting into this.

Jack
Click to expand...

I was talking to Chris in chat last night he doesn't carry the replacement crush sleeve that he was talking about. He said to go to randy's or Richmond for it. He does have the rebuild kits though for the 8 3/4's.
 
Coyote Jack said:
Mopardude,
I saw that article, I am going to print it out and study it throughly.

Chris,
You may get a phone call from me, I had already figured getting rid of the crush sleeve. Now I have to get to the point where I am comfortable getting into this.

Jack
Click to expand...

If you are going to put together a rear end don't forget you need some tools that are not in the typical shade tree mechanics tool box. I appologize if you are familiar with these tools but I didn't wnat to see you get into something without having the correct tools.

1. You need a dial indicator with either a magnetic base or a base you can bolt to the rear end. The dial indicator is used to measure the backlash between the ring and pinion as you move the side adjusters in an out.

2. You need and in-lb torque wrench, either a bean type of dial type is prefered to the click type. Do not confuse this with the torque wrench you use on head bolts, the typical bearing preload is less than 2 ft-lbs on the the typical troque wrench. Whether you use a crush sleeve or the solid spacer and shims you need to tighten the pinion nut enough to load the bearings so there is somewhere on the order of 15 in-lbs required to spin the pinion (without the ring gear contacting it).

3. A conventional torque wrench to set the side bearing preload and torque the bearing caps.

4. Either make or borrow a tool that will fit the 1 1/2" hex hole in the side adjusters that you can connect to your torque wrench. An old torsion bar will work in a pinch with a socket on the other end.

5. You will need some way to hold the pinion yoke while you tighten/lossen the pinion nut.

If you are going to call Randy's they have a video showing you how to do it. It was well worth the $15 before I did my first one.
 
dgc333 said:
Coyote Jack said:
Mopardude,
I saw that article, I am going to print it out and study it throughly.

Chris,
You may get a phone call from me, I had already figured getting rid of the crush sleeve. Now I have to get to the point where I am comfortable getting into this.

Jack
Click to expand...

If you are going to put together a rear end don't forget you need some tools that are not in the typical shade tree mechanics tool box. I appologize if you are familiar with these tools but I didn't wnat to see you get into something without having the correct tools.

1. You need a dial indicator with either a magnetic base or a base you can bolt to the rear end. The dial indicator is used to measure the backlash between the ring and pinion as you move the side adjusters in an out.

2. You need and in-lb torque wrench, either a bean type of dial type is prefered to the click type. Do not confuse this with the torque wrench you use on head bolts, the typical bearing preload is less than 2 ft-lbs on the the typical troque wrench. Whether you use a crush sleeve or the solid spacer and shims you need to tighten the pinion nut enough to load the bearings so there is somewhere on the order of 15 in-lbs required to spin the pinion (without the ring gear contacting it).

3. A conventional torque wrench to set the side bearing preload and torque the bearing caps.

4. Either make or borrow a tool that will fit the 1 1/2" hex hole in the side adjusters that you can connect to your torque wrench. An old torsion bar will work in a pinch with a socket on the other end.

5. You will need some way to hold the pinion yoke while you tighten/lossen the pinion nut.

If you are going to call Randy's they have a video showing you how to do it. It was well worth the $15 before I did my first one.
Click to expand...

Cool Thanks for the info!
 
dgc333,

You hit the nail on the head. It may not be worth it to me to do the job myself if I have to buy all those tools. I may take it to one of the local Dodge guru's and pay them to do it.

Jack
 
You might be better off taking it to a place that just specializes in axles or a 4x4 off road shop. They will likely have much more experience than brand guru.
 
they're usually less expensive, too

after all...do you want a general vehicle specialist or someone who does differentials for a living??
 
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