my experience with solid pinion bearing spacer

Hey all,

While rebuilding one of my 8.25 axles, I thought I'd try one of the RATECH solid pinion bearing spacers.

I put in 2 shims and got 22.5 in-lb of rolling torque. I figured this was good since spec is 10-30 for new bearings. Then I assembled the rest of the differential and got it all setup with backlash and put gear marking compound to check the pattern. All good.

Then I went to put the final seal and new yolk washer/nut on. Then not so good. I was suddenly at 55 in-lb of torque.

After scratching my head over this, I finally took the carrier out and it was still around 55 in-lb.

I took the pinion out and re-shimmed it a bunch of times ending up with 0.038 shims at 7.5 in-lb. I removed the yolk and re-installed it, and was up to around 12.5 in-lb. Then I did it again, and was up to 15-17.5 in-lb. Then I did it again, and it was still around 15-17.5 in-lb.

Has anyone else had this experience? I thought by rotating the pinion back and forth a few times while tightening down the yolk would have done the trick and the preload would have remained the same no matter how many times I took the yolk on and off.

Subbed....as I was looking at using this spacer too when I redo my pinion bearings for the umpteenth time

Perhaps when you first checked it a bearing race was not fully seated, and by tightening it all down a few times you seated the thing? Then playing with the shim combo you have to dial it in. It sounds like you are close at 17 in lbs. you can try to shim to get the 22.5 in pounds or leave it at 17.5 . the pinion seal will add a few in lbs to the thing too so that might get you up around 20-22 right there. Im just curious, but what BL are you running ?

md21722 said:

Then I went to put the final seal and new yolk washer/nut on.

Click to expand...

the seal will add an amount of resistance to your reading. that is normal. you should strive for proper preload with no seal.

I'm sure the seal adds a bit of resistance, but it does not add 32 in-lb.

I was at 0.065 backlash before I took it apart again.

I changed from 0.038 shim to 0.036 shim and it went from 17.5 in-lb to about 30-37 in-lb. Looks like I'll stick with 0.038 since the shim set is setup for 0.002 graduations.

A bunch of guides say 16-18 in-lb with new bearings, but the Chrysler FSM says 10-30 in-lb.

When you do a crush sleeve eliminator, take your reading with the seal installed. Since the eliminator goes between the bearings, you can change shims as it will pass thru the head bearing.

If the races are not seated all the way, the preload will loosen up not get tighter.

Did you have a washer under the yoke nut the first time? Was the slinger (big shim like washer .030ish thick that goes under the seal) installed? If not, then you probably bottomed out the yoke before you could apply full torque, which is why you got the light reading. _IF_ the yoke is messed up from taking it on/off a lot that can also make the yoke a few thousandths shorter.

Mine did not have a slinger by the seal. It could have been removed by a previous owner or their mechanic. I did use the original washer and nut and the nut shredded but I was able to torque things down. It's possible it was bottoming out but I don't think so because the nut was even thicker than the one in the rebuild kit. The yolk looks OK, except on the sides where my pipe wrench has been holding it in place. ;^) I planned on using the relatively new yolk on this axle (from the one currently under the Jeep). I have been using the recommended 125 ft-lb but I can do 150 ft-lb, etc. Its worth noting that going higher on the torque can/does increase the preload a bit.

I'll also say if you put the shims UNDER the spacer they will become bent inward a little and measuring with calipers can give funny readings. The spacer seems to stay .400. The spacer does not fit as tight as the crush sleeve to the pinion gear. All in all, I am fairly disappointed in this RATECH kit. I must have removed and re-installed that pinion shaft with different shims 20-30 times now and it seems like I either get 12.5-15 in-lb or 25-30 in-lb. I can remove and re-install the yolk repeatedly and its pretty consistent. I know once you get close on preload things change fast, but I would have really liked a 20 in-lb setting. I think 25-30 may be a bit too much.

Its hard to quantity rolling torque on a forum, but by feel you definitely notice it. I bet the guys who do this all day long can do this without measuring and get it where they want it.

One of the primary reasons I bought the spacer kit was because I planned on doing the axles on jack stands and its VERY difficult to crush a crush sleeve on a jack stand without the axle coming off the jack stands. Its MUCH easier to torque to 125-150 ft-lb than when you are working with 3-6 foot pipes and 3/4" breaker bars trying to get the 200-400 ft lb needing to crush the sleeve. My advise to anyone is if you are using a crush sleeve, have the axle under the Jeep or some method to hold the axle in place. Maybe a good impact would help.

And one last comment, I am using a Yukon master kit and the pinion yolk nut is 1-5/16". Fortunately I had that size, but only in 3/4" drive. I am used to 1-1/4" on these nuts.

Don't strive for a specific turning torque... you'll be there all day, as you've found. In spec is in spec. don't sweat it.
I like setting diffs on the tight side. They always loosen up.

It doen't matter if the seal is there or not. the drag it adds to the reading is negligible, and doesn't add to the true turning torque.

Thanks Digger, I was a bit concerned about setting it at the higher limit which was frequently touching 30 in-lb so I settled on the lower limit and torqued the pinion nut to 180 ft-lb which leaves me in the 15-20 in-lb range. I figure this way there is more room to work with while still being in spec. If I could've gotten 20-25 in-lb I would've stopped right there. Setting backlash is a piece of cake compared to setting the pinion rolling torque.. especially when you have a 8.25 with side adjusters instead of the shims on Dana axles. All in all, I'm pretty pleased I decided to do this because its been a great learning experience. I'll be smiling when this thing is finally under the Jeep and works as intended.

I have the Ratech and it worked fine on my 8.25

I find its common for the inner pinion bearing to back off the pinion slightly when installing, removing the nut, as well as the air hammer to drive the pinion out each time. The shock causes it.

I am not to sure how you removed the pinion or installed/removed the nut, but if it had any shock (hammer or air) then this is very poss.

Try driving the bearing on again then reassemble.

I used a dead blow hammer with a rubber/plastic type face. I was focused on not damaging the pinion threads. RWK, your suggestion makes sense. I got it all back together last night and changed the yolk to the older style because I had one with low miles that wasn't worn where the seal rides. Rolling torque stayed consistent. With the carrier installed it was 25-30 in-lb before and after the yolk change. Drove it about ~200 miles today, mostly highway, and it seemed to do fine. It is much easier to use a solid pinion bearing spacer than a crush sleeve once you learn to live with the available rolling torque settings achievable with the kit. All in all I would probably buy another RATECH spacer kit than deal with a crush sleeve. Even if the axle is bolted to the springs, using a crush sleeve, the 3/4" breaker bar and pipe have to come out.