I think I figured it out. (thinking out loud)

[TeamCF]

So I had the axle problem.

Which is fixed I'm over it. Sorta, cause I think it's gonna blow again, soon. Read on.

 

This may be food for thought on how new parts can break old parts. (Or other new parts that were not designed to accept the change)

 

First a bit of history.

One of my axles was 9 months old according to the recipt.

The other was 2 months old.

Both blew up at the same time on the same run right after installing the new strut tops. Odd.

 

I figured out why.

When I replaced my old strut tops. I actually gained about a 1/4" of ride height. And I gained about 3/4" of extra droop at full extension.

Reason is the fresh rubber in the strut tops. My old ones were basicly solid. When you jacked up the car they didn't flex.

The new ones are boosted up slightly and strech down when a tire is off the ground and the strut is fully extended. (I actually cranked down my adjusters to lower it some, but that won't stop the extension when a wheel is off the ground, as the adjusters only preload the springs)

I'm over extending the axles which EMPI proly never designed to be fully extended and turning. Like what happens while off roading.

 

So unless I put limiting straps on the front of my Soob.

Or drop the trans and engine some with out putting spacers at the struts.

I figure two wheeling trips will be enough to blow the new ones up too.

(I could be wrong though. Maybe I'll get 6 mos. out of them)

And one of those runs is gonna be tonight up to Goat after dark to see the Portland lights.

 

I'd better get ordering better axles.

 

Just thought I'd share what I found out from the whole thing.

[Loyale 2.7 Turbo]

... And one of those runs is gonna be tonight up to Goat after dark to see the Portland lights ...

 

Pics Please!

To Keep my Subie`s Axles Alive for More Time, I Do a Simple Trick: Before Close Turns (Like "U" Turns) I Give to the Subie Enough Impulse and Press full to the Floor the Clutch Pedal, Before the Turn; So it will Turn Without Giving Stress to the Axles...

Then After the Turn is Done, I bring Back the Clutch Pedal, and Accelerate when Wheels are Straight Again.

It Helps a Little for Sure.

[GeneralDisorder]

CV joints have some properties that must be respected if they are to work properly in a non-stock application.

 

1. The amount of torque a CV can handle is more or less inversely proportional to the angle it has to run at multiplied by the speed it is rotating. That is to say that the higher the angle and the greater the speed, the less torque it can transmit without catastrophic failure.

 

2. Failures of CV's fall into three categories for the purposes of this discussion. Thermal failures due to friction and heat, mechanical damage due to angles beyond the capabilities of the joint implementation, and axial loading causing the joint to physically separate.

 

Now - unless the geometry of the suspension has been modified (unlikely unless you have made custom control arms, knuckles, or strut's), then mechanical damage due to improper angles is nearly impossible. In fact a close inspection of the front axles shows they will not mechanically interfere with themselves till angles quite a bit outside the range of the stock suspension are involved. For the same reasons axial loads are not an issue either.

 

What it comes down to, if you study this problem in detail (believe me, I have), is that the stock axles fail in lifted applications due to the stock transmission gearing. The low range provided in the stock transaxle is not low enough to allow slow speed crawling with large tires over arduous terrain. This results in high-speed wheel spin (taking "runs" at obstacles) - often with the wheel completely off the ground and the suspension at full downward articulation. This causes rapid heat buildup due to friction - the moly grease quickly breaks down and the joint simply fails.

 

There are some things that can be done.

 

1. Replace the grease with a synthetic, high quality grease the will not break down as easily.

 

2. Repack the joints and inspect for wear after every trail run.

 

3. Be mindful of the limitations of the axles and avoid high speed wheel spin with wheels off the ground. Especially avoid having wheels spinning in the air and suddenly stopping when they come back to earth.

 

4. Stop periodically and let them cool down.

 

You can also lower your gearing so you don't have to drive the axles so hard. But you have to watch breaking other components. The stub axles are hollow and can be twisted off readily with too much torque. Similarly the diff gears would be next to take the brunt of the damage. And so forth back to the transmission.

 

Personally I'm most likely going with a bunch of nissan truck parts to overcome these problems. Nissan transmission, transfer case, and diffs. Modified Subaru axles run at flatter neutral angles so travel is split between upward and downward articulation.

 

GD

[TeamCF]

Pics Please!

 

My camera does not take very good night shots.

I tried. Sorry.

 

I'll have to take a good one up sometime (tinight with the moon would have been good,.... doh!) And get some.

[Loyale 2.7 Turbo]

Well... Mine Too...

Thanx!

[TeamCF]

CV joints have some properties that must be respected if they are to work properly in a non-stock application.

 

1. The amount of torque a CV can handle is more or less inversely proportional to the angle it has to run at multiplied by the speed it is rotating. That is to say that the higher the angle and the greater the speed, the less torque it can transmit without catastrophic failure.

 

2. Failures of CV's fall into three categories for the purposes of this discussion. Thermal failures due to friction and heat, mechanical damage due to angles beyond the capabilities of the joint implementation, and axial loading causing the joint to physically separate.

 

Now - unless the geometry of the suspension has been modified (unlikely unless you have made custom control arms, knuckles, or strut's), then mechanical damage due to improper angles is nearly impossible. In fact a close inspection of the front axles shows they will not mechanically interfere with themselves till angles quite a bit outside the range of the stock suspension are involved. For the same reasons axial loads are not an issue either.

 

What it comes down to, if you study this problem in detail (believe me, I have), is that the stock axles fail in lifted applications due to the stock transmission gearing. The low range provided in the stock transaxle is not low enough to allow slow speed crawling with large tires over arduous terrain. This results in high-speed wheel spin (taking "runs" at obstacles) - often with the wheel completely off the ground and the suspension at full downward articulation. This causes rapid heat buildup due to friction - the moly grease quickly breaks down and the joint simply fails.

 

There are some things that can be done.

 

1. Replace the grease with a synthetic, high quality grease the will not break down as easily.

 

2. Repack the joints and inspect for wear after every trail run.

 

3. Be mindful of the limitations of the axles and avoid high speed wheel spin with wheels off the ground. Especially avoid having wheels spinning in the air and suddenly stopping when they come back to earth.

 

4. Stop periodically and let them cool down.

 

You can also lower your gearing so you don't have to drive the axles so hard. But you have to watch breaking other components. The stub axles are hollow and can be twisted off readily with too much torque. Similarly the diff gears would be next to take the brunt of the damage. And so forth back to the transmission.

 

Personally I'm most likely going with a bunch of nissan truck parts to overcome these problems. Nissan transmission, transfer case, and diffs. Modified Subaru axles run at flatter neutral angles so travel is split between upward and downward articulation.

 

GD

 

Good points, and tips. The synthetic grease thing interests me...

 

I dove into it somewhat as well.

Actually took the axle apart that really went bad, I just had to see. (made sure I already had some good boot clamps on hand)

It was over extended. The bearings inside the DOJ had been contacting the retaining ring that sits in the groove on the cup. In comparison the EMPI's seem slightly shorter than my old ones, I could actually slide them off of the trans without having the suspension taken apart at all, my old ones needed the lower ball joint and the strut disconnected in order to get the clearance. Which seems odd as I would think they would have just made them to Subaru size specs....

Or maybe Discount's book is wrong. Which is very unlikely as they do fit everywhere else.

Wish I would have thought to get a bunch of pics. But I was more concerned with a quick peek so I could get the hour drive each way to exchange it overwith.

 

The gearing thing is the whole reason I'm not going over 26" tires.

At least not until I get to the point of just replacing the drivetrain like you are planning. Cause like you say, wheelspin is the enemy, I hardly ever get much past 2,000 rpm in first LO when I wheel. Even on steep hills I always try to keep it just over lugging/stall. If I wanted to get the speed in the dirt I would have stayed with RallyCross. I never understood the "Taking runs at things" Just not good wheeling to me. Rather try to crawl over big obstacles with small tires, than have to blast over small obstacles with big tires.

 

Oh well.

It's rolling again, and I'm gonna invest in some Genuine, or MWE's to have on the shelf for next time.

[michael appel]

Just let me suggest one thing buy junk yard axles they are three times cheaper and if you are wheeling like you and me you break them I have a supply of innards for the doj and also full axles laying around that I picked up from the junkyard its cheap you get original subaru parts and its cheap at least for something that will give during wheeling events also I leave my sway bar on the front because with a locker in back I dont care if I lift a tire up front and I like the handling on the road

[TeamCF]

Just let me suggest one thing buy junk yard axles they are three times cheaper and if you are wheeling like you and me you break them I have a supply of innards for the doj and also full axles laying around that I picked up from the junkyard its cheap you get original subaru parts and its cheap at least for something that will give during wheeling events also I leave my sway bar on the front because with a locker in back I dont care if I lift a tire up front and I like the handling on the road

 

Yeah I gotta get over the the JY near me and see what they have.

I know they purged thier old Suby collection a while back, but should have a bunch more by now.

 

I don't even know if I can put my sway bar back on with how my exhaust has been tucked up for more clearance (had the shop do it after I removed the bar). Could try though and see how I like it. Need new bushings for it out at the ends though. Mine were basicly gone when I took it off. Pretty much metal against metal. Proly find some decent ones at the JY.

 

Nice part about welded though is you don't have to do alot of tire spinning. So not so much fast wheelspin up front when it does lift.

[michael appel]

you ever need anything like axle parts next time i go up to the jy ill get you some parts to rebuild