RD31 ARB locker install help (backlash)

[KingCarGuyZ]

Alright, I'm not going to lie. I'm probably in over my head at this point and I should probably hire a professional - but where's the fun in that? So despite my better judgment I'm determined to install this myself. That being said I could use some help from anyone that is familiar with gears/ locker installs.


The problem is a simple RD31 (old stye for 3.07 gears) ARB locker going into a Dana 30. Im re-using the same ring gear and have followed the manual to a T, I have all of the holes drilled and everything seems like its going to work but I can't for the life of me get ANY backlash. I managed to get the desired 7 thou without the bearing caps on, but after installing the bearing caps we're back to no measurable lash. I currently have .50 thou of shims on the drivers side of the carrier and am struggling mightily to actually install the carrier into the housing. like get the 3lb hammer and wood block and have a very strong discussion to get the carrier in, there is a lot of preload on the bearings.

The stock open differential comes and goes from the housing with nothing more than a good shove and has 8 thou of backlash.

I am at a loss. I can only assume I am missing something simple and for some reason the ARB ring gear is to close to the drivers side of the carrier when compared to the open diff. Why? - no idea. Is it normal to have this much preload and this difficult of an install? Do i need to make a diff spreader and get the hammer just to get this locker in? does the fact that my axle is at full droop have anything to do with this binding?

On the 3rd or 4th install attempt and I broke the seal housing this time (shocker) so I am currently on hold until a new part gets here, IG now I at least have a ""setup" housing that I don't have to worry about killing. I welcome any ideas, I'm kinda scratching my head here.

 

[NashvilleTJ]

If I recall correctly, ARB recommends something like 15 thou preload on the carrier bearings - that’s tough to get correct without a case spreader. And ARB absolutely recommends using a case spreader to do the setup.

Assuming your pinion depth is set correctly, if you are getting 0 backlash it means your shim stack is pushing the ring gear to far into the pinion gear. Reduce the shim stack on the ring gear side and increase it on the opposite side In order to move the ring gear away from the pinion gear.

What do your patterns look like? If you post them up there are a bunch of knowledgeable folks here who can help interpret.

 

[KingCarGuyZ]

If I recall correctly, ARB recommends something like 15 thou preload on the carrier bearings - that’s tough to get correct without a case spreader. And ARB absolutely recommends using a case spreader to do the setup.

Assuming your pinion depth is set correctly, if you are getting 0 backlash it means your shim stack is pushing the ring gear to far into the pinion gear. Reduce the shim stack on the ring gear side and increase it on the opposite side In order to move the ring gear away from the pinion gear.

What do your patterns look like? If you post them up there are a bunch of knowledgeable folks here who can help interpret.

gotcha ill build. case spreader and try again, haven't run a pattern cause cause the gears seem so tight - guess I could try

 

[hosejockey61]

gotcha ill build. case spreader and try again, haven't run a pattern cause cause the gears seem so tight - guess I could try

You don't need a case spreader. Since you now have a "setup" seal housing, it shouldn't be as frustrating.

I'm assuming the RD31 has the correct bearings? ARB's use different carrier bearings to allow for the seal housing. They also use ARB specific master shims.

I would make a big shim change from the left side over to the right. Try to get too much back lash. Once you do that, then the fight is over.... Simply start making small adjustments from the right back to the left until it tightens up to spec. It might make it a bit easier to pull some shims to reduce preload until you can get it in the ballpark.

It will do you no good to run a pattern until your backlash is in spec. Also, if all you are doing is swapping the carrier for the locker, you shouldn't need to pull the pinion out make any adjustments to it.

 

[NashvilleTJ]

You don't need a case spreader. Since you now have a "setup" seal housing, it shouldn't be as frustrating.

I'm assuming the RD31 has the correct bearings? ARB's use different carrier bearings to allow for the seal housing. They also use ARB specific master shims.

I would make a big shim change from the left side over to the right. Try to get too much back lash. Once you do that, then the fight is over.... Simply start making small adjustments from the right back to the left until it tightens up to spec. It might make it a bit easier to pull some shims to reduce preload until you can get it in the ballpark.

It will do you no good to run a pattern until your backlash is in spec. Also, if all you are doing is swapping the carrier for the locker, you shouldn't need to pull the pinion out make any adjustments to it.

Appreciate your expertise here, HJ. How do you get enough preload on the ARB without a spreader?

I have a good buddy who tried to do an ARB in a 60 front without a spreader - and it always leaked. Once he used a spreader and got the correct preload, it was fine.

 

[KingCarGuyZ]

You don't need a case spreader. Since you now have a "setup" seal housing, it shouldn't be as frustrating.

I'm assuming the RD31 has the correct bearings? ARB's use different carrier bearings to allow for the seal housing. They also use ARB specific master shims.

I would make a big shim change from the left side over to the right. Try to get too much back lash. Once you do that, then the fight is over.... Simply start making small adjustments from the right back to the left until it tightens up to spec. It might make it a bit easier to pull some shims to reduce preload until you can get it in the ballpark.

It will do you no good to run a pattern until your backlash is in spec. Also, if all you are doing is swapping the carrier for the locker, you shouldn't need to pull the pinion out make any adjustments to it.

Awww hell…..

Now that you mention it I think they are just standard Dana 30 carrier bearings, I’m guessing there’s a significant difference? The pains of piecing parts together, I do have the shim kit and master shim.

Wonder how many tricks I can remember for pulling off bearings….

 

[hosejockey61]

Appreciate your expertise here, HJ. How do you get enough preload on the ARB without a spreader?

I have a good buddy who tried to do an ARB in a 60 front without a spreader - and it always leaked. Once he used a spreader and got the correct preload, it was fine.

I do it the same way I set up regular gears, deadblow hammer. I've set up a lot of ARB's and have never had an issue.

A case spreader would certainly help, especially with installing the seal housing, but it isn't required.

 

[KingCarGuyZ]

I do it the same way I set up regular gears, deadblow hammer. I've set up a lot of ARB's and have never had an issue.

A case spreader would certainly help, especially with installing the seal housing, but it isn't required.

New problem, got the correct bearings on and now I am struggling to get enough preload to have any backlash. I can easily install the carrier, but when I start to get more shims the carrier becomes almost impossible to install. I have yet to been successful at getting any backlash. When the locker is installed without preload, it does not want to rotate and when it does it has "notches". I'm guessing I just need to shove more shims in, one way or another?

With noting, I have no shims on the passenger or ring gear side, all shims are no the drivers side to move the ring gear further away from he pinion.

Thoughts?

 

[hosejockey61]

New problem, got the correct bearings on and now I am struggling to get enough preload to have any backlash. I can easily install the carrier, but when I start to get more shims the carrier becomes almost impossible to install. I have yet to been successful at getting any backlash. When the locker is installed without preload, it does not want to rotate and when it does it has "notches". I'm guessing I just need to shove more shims in, one way or another?

With noting, I have no shims on the passenger or ring gear side, all shims are no the drivers side to move the ring gear further away from he pinion.

Thoughts?

Your statement doesn't make sense. What do you mean you aren't getting enough preload to get backlash? It's simple. Add shims until you have a snug fit. Then move shims from one side to the other until you can get backlash in spec.

 

[Jezza]

I use a case spreader. Yes, you can do it without, but why? They are cheap enough and make it so much easier. In my experience most folks don't run near enough carrier preload because they don't want to struggle with a tight install. Improper preload on the carrier can lead to gear misalignment and damage to the gears and bearings.

 

[KingCarGuyZ]

Your statement doesn't make sense. What do you mean you aren't getting enough preload to get backlash? It's simple. Add shims until you have a snug fit. Then move shims from one side to the other until you can get backlash in spec.

It seems simple enough in my mind as well, it it keeps not working…. Have to assume user error. At this point I managed to get enough shims on the drivers side to get 7thou backlash, but I have just under .200 of shims, which seems excessive.

Now I am having a problem where I can install the locker, hand tighten the caps and everything is fine, I can tighten the drivers side cap to spec, but the second I tighten the passenger side cap any more than a loose hand tight, the whole assembly locks up solid. Maybe something is out of alignment?

 

[Jezza]

If it tightens up when you torque the caps the backlash is likely still too tight.

 

[KingCarGuyZ]

If it tightens up when you torque the caps the backlash is likely still too tight.

I'll try adding more shims to the drivers side then, should I be concerned at the current .200 shim pack?

This locker is continually kicking my tail.

 

[hosejockey61]

A few questions for you...

1. What gear ratio are you going to?

2. Are the gears new or used?

3. Did the housing have thick master shims outside of the bearings?

4. Stock low pinion housing or high pinion from an XJ?

 

[KingCarGuyZ]

A few questions for you...

1. What gear ratio are you going to?

2. Are the gears new or used?

3. Did the housing have thick master shims outside of the bearings?

staying with the 3.07's that came with the jeep originally (IK,IK - but I need the HWY cruise), it is the old RD31 locker for 3.55 (or 3.57 can't remember which) and numerically lower.

The stock open carrier had no "master shims" to the outside of the carrier bearings, all of the shims are pressed underneath the carrier bearings no the stock carrier (can confirm they are there, I had to replace a carrier bearing a while ago and replaced the shims along with it)

appreciate the help, I have watched your video on the newer style of ARB's and thought I had this pretty much down pat - I have had this axle apart 4 time since then...

 

[hosejockey61]

Ok, since you're keeping the same gears, and after re-reading this thread, it sounds like all you are trying to do is swap out the old carrier and replace it with the ARB.

Because ARB uses a seal housing, you will have to figure out new shim stacks for each side. Instead of trying to force it in every time, add just enough shims that still allows the locker to be pulled out by hand. Worry about preload later. The seal housing MUST be placed to have air hole in the journal (on the locker) rest between the two O rings in the seal housing. Place shims on the seal housing with the ARB master shim going against the bearing. Usually the housing has a thick (roughly .100) shim and that would go between the seal housing and the pumpkin. You'll have to bill a thick stack. You can add thinner ARB shims at the seal housing and keep the thicker ones to the outside.

Once you move shims to establish backlash, then add an equal amount to both sides to acquire preload. Check your backlash and adjust as necessary.

 

[Rickyd]

Did you measure backlash before taking it apart?that is step 1 with a carrier swap on old gears. When changing a carrier you adjust shims to replicate the old backlash so the gears are happy.

Hosejockey nailed it.use enough shims to make it nice and snug for a backlash reading.then add preload when done.

Laquer thinner(or brake clean) and compressed air are your friends too. Clean clean clean makes for repeatable readings.

 

[Rickyd]

staying with the 3.07's that came with the jeep originally (IK,IK - but I need the HWY cruise)

Those don't look like 215/75-15 tires in your avatar...... You need an intervention with those 3.07s

 

[KingCarGuyZ]

Ok, since you're keeping the same gears, and after re-reading this thread, it sounds like all you are trying to do is swap out the old carrier and replace it with the ARB.

Because ARB uses a seal housing, you will have to figure out new shim stacks for each side. Instead of trying to force it in every time, add just enough shims that still allows the locker to be pulled out by hand. Worry about preload later. The seal housing MUST be placed to have air hole in the journal (on the locker) rest between the two O rings in the seal housing. Place shims on the seal housing with the ARB master shim going against the bearing. Usually the housing has a thick (roughly .100) shim and that would go between the seal housing and the pumpkin. You'll have to bill a thick stack. You can add thinner ARB shims at the seal housing and keep the thicker ones to the outside.

Once you move shims to establish backlash, then add an equal amount to both sides to acquire preload. Check your backlash and adjust as necessary.

That is correct, "just" swapping the open diff for one of the older style ARB units.

I'll attack again in the morning - as I understand it the seal housing sits on the bearing cup and then you add your shim stack between the seal housing and the master shim, correct? Currently I have 94thou of shim stack + the 100thou master shim (I think it might actually be 98thou, have to look a my notes) and I still can not get backlash with the bearings caps installed.I did install the locker with no shims and came up with a total of 170thou space between the seal housing and the diff. case. At this point, there is some bearing pre-load, but there are no shims on the ring gear side, so IG I am essentially adding preload in the hopes of taking up bearing slack and finding backlash? Seems like something I shouldn't need to do but near as I can tell thats where I am at.

 

[KingCarGuyZ]

Those don't look like 215/75-15 tires in your avatar...... You need an intervention with those 3.07s

31's, so it's not "that bad" but I deffinelty have a good relationship with WOT. I'm a broke HS kid so its kinda a run what you brung for now. Eventually I might diesel swap her and maybe fix the 3.07 to 4.10's or steeper.