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Need help reassembling Chrysler 8.25 rear axle...

C

canyonfireguy

NAXJA Forum User
Location
CO
Greetings all,

My forward pinion bearing and race rusted and started making a growling noise so I'm doing new ring and pinion gears and installing ARB air lockers while I'm in there. I'm struggling a bit understanding the right way to set pinion depth on the 8.25 or if you even need to. On disassembly, there were no shims installed, and the only ones that came with my G2 master pinion install kit are the smaller ones for the forward (small) bearing and race, so they would not increase pinion depth but only change preload, which I understand to be unnecessary on the 8.25 due to the crush sleeve.

I spent hours grinding down the old races to make test or fitting races that don't have to be pressed in to set the preload, but there are no shims in the kit to put behind the larger rear race to increase pinion depth. I'm not sure if I need that yet or not, but I'm hesitant to install the pinion and carrier and pattern the gear contact without having a way to adjust pinion depth if necessary. I also don't know whether to install it with the old or new crush sleeve or not at all to test the pattern, or which nut to use to seat the yoke and bearings.

Appreciate any help getting this done right. Thanks.
 
Pinion depth is usually done based on the "markings" on the gear set itself and they don't lend themselves to "laymen" easily! For the backyard mechanic it's usually "trial and error", you need to order up a full shim set if yours came with limited shims. Are you changing ratio's?
 
Thanks for the reply. Yeah, I am going from the factory 3.07s (manual trans) to 4.10s to get some of my low end back after the lift and 33s. I have been watching every youtube and reading every walkthrough I can find, but they all seem to contradict one another. All of the really well done videos on setting pinion depth are done on Dana axles, and all of the decent ones on the 8.25 focus on backlash and omit pinion depth altogether. Almost like the side loading collars on the 8.25 eliminate the need to set pinion depth, but that makes no sense to me, as side to side movement does not make up for a pinion gear that is too deep or too shallow.

I have the "test fit" bearing races, marking compound, acid brush, and backlash gauge at the ready. I was just really surprised to see that there were no large diameter shims in the kit to back that bearing race out and increase pinion depth. Also, all of the walkthroughs say to start with the same amount of shims, yet many others say that 8.25s don't use them. Mine certainly had none. And as I stated in the original post, no one in the walkthroughs really clearly says whether you use the old, new, or no crush sleeve when test fitting for pinion depth, and I know you only get one shot at crushing that.

Thanks for your input.
 
You can use the old crush sleeve for checking the pinion depth as things don't have to be fully torqued.
 
Per the Factory manual there is supposed to be a pinion depth shim between the inner bearing race and the case of the housing to insure proper depth of the pinion. If there was not one there from the factory you'll need to check the pattern on the gears and check the preload with a torque wrench, need to get a set of shims to correct the pattern if the pinion is too shallow, backlash is another thing that is adjusted with side shims and pinion depth. Good luck on your build.
 
The shims your got in your g2 kit are for pinion depth; those are the only shims that should've came in the kit and should only be used for pinion depth between the inner bearing and the toothed end of the pinion. I would start with no-shims on your new install, torque the pinion (without crush sleeve), set backlash, and get a clear pattern reading. You will then know if you need to add pinion shims (which you likely will).

You may be confusing Dana axles with the 8.25. On the 8.25, pinion preload is set by a crush sleeve....and that is installed only after you set pinion depth with the provided shims.

The threaded adjusters absolutely do not negate the need for pinion depth...they are only there for backlash and carrier bearing preload.
 
*I seriously hate that edits can't be made* It is likely the absolute worst feature of this forum. We don't have the same numbers as we used to, and the flame backtracking/pure stupidity barely exists anymore.

Anyway....

By "torque the pinion (without crush sleeve)" I mean tighten the pinion nut until you get the proper preload prior to moving forward with setting backlash.
 
gearwhine said:
*I seriously hate that edits can't be made* It is likely the absolute worst feature of this forum. We don't have the same numbers as we used to, and the flame backtracking/pure stupidity barely exists anymore.
Click to expand...

Red letter members can edit.
 
The reason why some videos don’t show the entire process, is there’s at least 3 or 4 ways to do EVERYTHING with gears. Videos as a tutor for gears is inadequate. Asking on forums is even worse! One guy will tell you to put the old crush sleeve back in, then the next guy will say that’s stupid! Just leave it out and tighten til your pinion preload preload(PP) is in the ball park.

PInion depth (PD) is either done via shims on the pinion head, under the bearing, or under the inner pinion bearing race. I couldn’t tell you which is is on that axle though. Plus maybe the last guy changed it because he only had shims to do it one way.
 
canyonfireguy said:
or which nut to use to seat the yoke and bearings.
Click to expand...

I do not install a brand new mechanically locking pinion but until:
1: pattern looks good.
2: crush sleeve is compressing
3: pinion seal is greased, rtv’d, and installed.
4: yoke seal edge is greased, and splines are sealed. (Older parts only)

Stover nuts loose 25% of their retention Everytime you remove them. One time install only!*

* exceptions are made everyday.
 
Update: per the 4WP guys, the reason that there are no shims for the inner pinion bearing race in the kit is that they expect you to shim between the gear head of the pinion shaft and the inner pinion bearing. This seems like a horrible idea though, as you would have to mod the old bearing to open up the inner diameter so it can be slipped on and then use it to get your shim stack right, and then press the bearing on with the shims under it and hope like hell that they are not a few thousandths different. Seems like a wonky plan to me. My OEM pinion shaft had no shims anyway. Much easier to turn down the outer rim of the old bearing race and shim behind it. That way, even if it's not perfect on final assembly, it's a lot easier to knock out a race than to pull your pinion bearing without damaging it. I'll be ordering a shim kit with the proper shims to go behind the race. Doubt I will even need them, but I want them on hand for when I do the fitting and patterning. Thanks again to all for the help.
 
Behind the head of pinion is industry standard, and many, MANY diffs are done that way.
If you have to press the bearing on and off a couple times to get your pattern right… welcome to doing gears!

I prefer them shimmed behind the pinion head… it’s easier to get a pinion bearing off, than it is removing a inner race that has a baffle behind it.

As far as setup bearings, it’s JUST AS EASY to grind out the inside diameter, so I dunno what all the fuss is about…
 
It's really not though. Much easier to turn down the outside of a race than the inside collar of a bearing that turns as you work it. It's also a terrible idea to press your inner pinion bearing on and pull it off repeatedly. Much easier to use test fit races so you can just get the shims right without having to press anything in, pull bearings, or knock out races. I appreciate your opinion on it, but no need to be judgy and snarky. If it's industry standard why didn't 4WP know about it when they sold me the kit? Their gear experts said to shim behind the race. I'm learning as I go here, but the bad information about how this is to be done is rampant. As one member said in this thread, if you ask 4 guys how this should be done, you'll get 4 answers. Minimum.
 
Canyonfireguy... it sounds like you are unsure of what you're doing (which is completely ok!), but it seems you're telling everyone that the advice they're giving is not correct. Many users here have done re-gears on the 8.25 many times. I just did one in December. We're not always right, but you're getting consistent advice throughout this thread. If you want to do it without the advice...just go for it.

Don't expect 4WP to know anything. They are professionals in service; they are not good at service. "Professional" and quality/knowledge are two entirely different things. This group here has intense knowledge of XJs specifically, not the 1000s of vehicles that 4WP works on. I can generally guarantee you will not get better advice on the 8.25 there than you will here.

The 8.25 does not shim behind the race (you can do it with the correct shim sizes, but it's not the norm. I don't know any re-build packages that provides shims for this purpose). For reference; the Dana 30 DOES use shims behind the race. Re-pulling and re-pressing the inner bearing on and off to change depth shims is the norm, and will not damage anything if you have the proper tools.

My opinion - I hate test bearings/races. I have tried them many times; they can help get me close-ish, but I have never once got a final set-up with them. I just use the new bearings/races from the get-go.
 
gearwhine said:
Canyonfireguy... it sounds like you are unsure of what you're doing (which is completely ok!), but it seems you're telling everyone that the advice they're giving is not correct. Many users here have done re-gears on the 8.25 many times. I just did one in December. We're not always right, but you're getting consistent advice throughout this thread. If you want to do it without the advice...just go for it.

Don't expect 4WP to know anything. They are professionals in service; they are not good at service. "Professional" and quality/knowledge are two entirely different things. This group here has intense knowledge of XJs specifically, not the 1000s of vehicles that 4WP works on. I can generally guarantee you will not get better advice on the 8.25 there than you will here.

The 8.25 does not shim behind the race (you can do it with the correct shim sizes, but it's not the norm. I don't know any re-build packages that provides shims for this purpose). For reference; the Dana 30 DOES use shims behind the race. Re-pulling and re-pressing the inner bearing on and off to change depth shims is the norm, and will not damage anything if you have the proper tools.

My opinion - I hate test bearings/races. I have tried them many times; they can help get me close-ish, but I have never once got a final set-up with them. I just use the new bearings/races from the get-go.
Click to expand...

Where’s the like button?
 
gearwhine said:
Don't expect 4WP to know anything. They are professionals in service; they are not good at service. "Professional" and quality/knowledge are two entirely different things. This group here has intense knowledge of XJs specifically, not the 1000s of vehicles that 4WP works on. I can generally guarantee you will not get better advice on the 8.25 there than you will here.
Click to expand...


This deserves to be emphasized.


There is a distinction which has been lost in the English language. Generally speaking most folks think a professional does better work than an amateur. While that can be the case, it is not the full truth. The true amateur will do better work than the professional.


There is a reason for that.


The professional is in it to make a buck. The amateur is in it for the love of it (amateur shares the same root as "amor"). The professional will cut whatever corners he can to maximize his profit. The true amateur will take the time to do the best possible job.



I will grant that the word amateur has been co-opted to include those who don't have a clue what they are doing, but just go for it anyways, but that is not the original meaning of the word.



On this site you are getting advice from those who have a passion for this particular vehicle platform, IOW, true amateurs. The "professionals" can't measure up to the true amateurs. The money is elsewhere.
 
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