HELP! Blew my 2nd RF inner axle joint in 2 weeks. Cracked spring maybe?

[ItsaWykydtron]

85 Eagle. About 2 weeks ago leaving a snowy parking lot in 4 wheel drive while moving straight ahead through an intersection I gunned it a little bit and heard a bang and then thump thump thump. I was expecting front driveshaft or something but I was surprised to see my right front inner half shaft joint was pulled apart.

I replaced this axle with an aftermarket new part from Rock Auto in March 2017 after the old axle had an outer joint fail from a boot that had been torn from before I got the car. Ive been driving on it fine since then in both 2x4 and 4x4. I replaced the axle this time with another surtak/trakmotive from rockauto and initiated a warranty claim. Hoping maybe it was a bad part. FWIW these half shafts are using a tripod style inner joint.

Fast forward to this morning it happened again as soon as i engaged 4x4 on a snowy road.

When this initially happened I was theorizing maybe it was worn motor mounts but they checked out ok. When I had the car on the lift the other day I couldnt find anything to blame other than a cracked spring on the same side. I am currently riding about 1/2" lower on that side. I have all the parts to fix the springs, shocks, bushings and ball joints this weekend. But I am really worried Im going to keep blowing these inner joints.  Im wondering if they are too short. maybe I should try another source.

I see the last post in this section was about this same topic back in October. I posted over there too, so hopefully OP sees it. Anyone else dealt with this?

[mudkicker715]

I have seen 2 different sizes. Not certain why. Maybe 4 cyl to 6cyl differance. However its obvious to see the size change.

[ItsaWykydtron]

It's possible, every where I've checked only offers one part number for either side. All the axles I've taken out or installed looked the same.

[mudkicker715]

I haven't used photobucket in ages. Here is what dug up from that trainwreck site.i thought i had better pics but it is somthing to show my experience on the different halfshafts

[AMC of Houston]

From the parts manual:   The 4-cylinder inner CV housing is 3.75 inches in diameter.   The 6-cylinder inner CV housing is 4.33 inches in diameter.   However, there is no mention in the manual of any length difference between the two.   Obviously there is also a length difference as shown in MudKicker's pics!   May have the shorter one where the longer one should be!

[ItsaWykydtron]

Thanks guys, this is very good information. I will check that today at the shop. In the meantime I sacrificed the axle I was going to return so I could have a stub axle to bolt in place and avoid a tow truck. If this problem persists I may just be 2wd for a while.

[ItsaWykydtron]

Well guys it looks like you're into something. The inner CV I've been riding around on for a year and a half is questionable. Because it's a new part it is not like either of the pictured housings but it might be more similar to the 4cyl. Is there a spec on compressed length?

Side note: we lost power last night and this morning while dealing with that I also managed to throw the stub axle in. Hopped in, got the eagle unstuck in the ice and pulled out onto the road only to find the brake pedal going to the floor! Gotta love it. I had brakes on every 4th pump so I gently drove it to work. At least it's here now(I work at a shop).

[ItsaWykydtron]

I just ordered a carquest axle (bottom) from advance. Look at the difference. I think this is it.

[AMC of Houston]

I checked the relevant manuals, and there's no mention anywhere of any length spec at all, except for the installed length of the boots.   It does mention that when the boots are installed, there should be a 1-1/8" gap between the small ends of the CV boots on 4-cyl cars; but no gap on 6-cyl cars (the boots butt up against each other.   That kinda implies that the 4-cyl inner joint is ~1-1/8" inch shorter than the 6-cyl joint.   Note that the parts books show all other axle parts to be the same; only difference mentioned is the inner joint.   Wish I had one of each to measure!

The old joint in your pic definitely looks too short!

[ItsaWykydtron]

I've still got a new surtrack at home I'll post comparison pics when the carquest one shows up. I feel pretty good about this so far. Thank you both for your help!

[amarshall]

I don't know about the spec, but I had a similar experience with a Surtrak unit.  I tore the inner boot on my RF half shaft when replacing the front springs, so I took it out and swapped in a new Surtrak.  It exploded about 1000 miles later, on a dirt road during a sharp turn in 4wd mode.  Luckily I had the original unit as a spare, and was able to get it swapped back in after a boot change.

Here are the pics I have, in case they help.  I was able to score another original unit from another member here, and I got a warranty replacement for the Surtrak also.  So I have plenty of spares, but I've done another 2500 miles of rough trails since putting the original back in, no problems at all.

[ItsaWykydtron]

Thanks. Definitely looks shorter. I really hope I can get Rockauto to stop selling these so no one else has to go through this.

[mazdamike]

Same problem same parts(rockauto). Oreillys sell both length shafts,  going to order the longer (18. 1/4) length see if that fixs the problem.

[ItsaWykydtron]

What size do they list the shorter one? The Rockauto ones are 18 1/8.

My carquest axle won't show up until Tuesday or Wednesday. I don't have oreilleys near me but if that works for you I guess I could order one from them online.

I got one half of my front end rebuilt yesterday. The extra ride height will need the proper axles even more so.

[Draekon]

Iirc, ranger axles are slightly longer and have the correct splines/flange. Might be worth looking into if you have a lifted front end