CHRY 9.25 rear axle issue.

[justtorchit]

RANT with questions to follow

I did a gear job over the weekend on a freinds truck. its a chysler 9.25 rear in a dakota r/t. He had a bad whine coming from the rear that someone previously re geared. so i told him to bring it over and we will put new gears and bearings in.

I personally hate this axle. My Old work van had this axle and had problem after problem with the carrier bearings. the techs could never get the thing to shut up. ive seen a few others that had blown to pieces. And ive heard people can never get them to stop whining.

So i check the pattern on the gears from teh old setup and it was waaaaayyyyy out of wack. there was hardly any contact patch on the teeth and the gears looked like shit. So i break it down and do a full overhaul on it.

Well i got the thing perfect (wish i took pictures). perfect pattern, perfect backlash yada yada yada. I loved how easy the gear job went because of the side adjusters. I did a little research and found that randy (randys ring and pinion) did some testing with this axle and found that the side adjusters need 150 to 200 ft lbs of torque to keep a preload on the carrier bearings. so i set them to 150 ft lbs. Took it for a test drive and it ran so smoothly.

well i get a call back that the rear started to make noise with about 120 miles on it. he said it was great then he did a burnout to show off to his neighbor and parked the truck. took it out the next morning to go to work and it was whining like a bitch. drove it to work then to my garage last night (80 miles?) and IT WAS BADDDDD. sounded just like it did when he brought it over teh first time. Its a complete loss.... got over the fact of the wasted money and we started to look into the root cause.

The backlash in the carrier was unbelivable. gears were toasted.. poked around and found we could move the carrier back and forth a good eigth inch. so obvioulsy no preload on the bearings. so i pull a cap off and see the bearing isnt even seated in the race and the adjuster had no threads showing unlike when we put it together. so i check to see what the side adjusters had for torque on them and i could do 2 full turns before they even got tight. (thats like a good 1/4 inch...... so basically we found that the side adjuster backed out some how. and that the retainer didnt do its job. (i questioned the retainer that they used when i put it together becasue i couldnt believe it would hold the adjuster in place) so i asked around about the retainer and was told on the full size 9.25s they have an internal jam nut type of lock that you set from a few sight holes in the housing...... well what would you know, the sight holes that are in the housing have a axle tube in the way so it would be impossible to retain the adjuster that way. Basically it looks like chrysler needed a big axle and said:
"lets just throw a fullsize axle in this little truck. we can just press the tubes in a little more....... OH SHIT, WE CANT LOCK THE ADJUSTERS NOW. lets use these useless L clips that wont do shit to hold the adjuster in place"

so what we think is that the adjuster backed out and when he did the burnout it put a large load on the ring gear and pushed the race out to hit the adjuster. then driving it like that lead to catastrphic failure.


So here are my tech questions.

What would your next step be?

would you try re gearing it again with new bearings and gear set?
(this problem obviously happend twice)

maybe try locktight on the adjusters?

find a new way to lock the adjusters?

or would you be like me and say fuck this axle, cut your losses, and build a 9 inch or 60 semi float?

what years and what vehicles came with a semi float 60?

Any other axle suggestions? its a odd 6 lug axle, but im sure redrilling would be cake.

Input would be greatly appreciated because i feel like shit that this happened, and i want to help him get it fixed.

[ct67_72]

I have done these, and only had one issue.
The last one must have had dirt, or something in the side adjuster. It only takes a tiny bit for it to bind up and feel like its preloaded, and actually still be loose. and until the carrier has a good load on it, it feels fine.
I think one of the problems is that the carrier races dont sit perfectly true when you torque the adjusters, or only move so far and dont really preload the bearing, but just load the adjuster against the race.
I try to only lightly torque the carrier bearing bolts, so that the carrier can move a bit, then set the tension, then smack the carrier back and forth with a brass hammer while turning it to make sure the bearings cant move in the carrier caps and recheck.

[justtorchit]

I have done these, and only had one issue.
The last one must have had dirt, or something in the side adjuster. It only takes a tiny bit for it to bind up and feel like its preloaded, and actually still be loose. and until the carrier has a good load on it, it feels fine.
I think one of the problems is that the carrier races dont sit perfectly true when you torque the adjusters, or only move so far and dont really preload the bearing, but just load the adjuster against the race.
I try to only lightly torque the carrier bearing bolts, so that the carrier can move a bit, then set the tension, then smack the carrier back and forth with a brass hammer while turning it to make sure the bearings cant move in the carrier caps and recheck.

My buddy watched me do the whole setup and i am completely anal about everything being clean. i know that was not the issue. lol

I also know that the adjusters were loaded against the races, and the races were seated on the bearings. the races "easily" slid back and forth in the torqued bearing caps when you put pressure on them with the adjusters. we would get the backlash close. torqued each adjuster to 40 ft lbs. (when you torqed one side the oposite side would be at the same torque,therefore i know there was no gap), then checked the backlash and dialed it in till both sides had 150 ft lbs on the adjusters.... I KNOW there was preload on those bearings.

the retainer on the adjusters is a horrible design. maybe becasue they were used multiple times they no longer held pressure on the adjuster. i dont see how it did much of anything even if the retainers were new. on every other adjsuter style rear end ive done, the retainers clip into somethign so the adjusters cant back out. When taking it apart one of the adjusters was noticably backed out because there was no longer adjuster threads showing through the housing. So im positive that was the issue.

I wish when i put it together the first time i knew of this issue, i would have checked to make sure the retainers were actually putting pressure on the adjusters.

have you done any full size 9.25s? the guy i was asking on 9.25's said the adjusters were retained diffrently on the full size ones. and he looked at the way this axle is and said it was a horrible design. (i wish i snapped some pictures)

[ct67_72]

Yeah I did a full size one. The "locks" that hold the spanner collars have 2 "teeth" Ill call them. They are supposed to kind of bite into the collar and hold it from backing out. I tried to find a pic and cant find one that looks like the one I did.
If it has the "finger" style lock make sure that the collar isnt backwards. If it is the "finger" has nothing to lock into.
I wish I could find the pic, the lock was basically a 90 degree piece, it bolted to the cap flat, bent 90 degrees and was cut like 2 triangles that jabbed into the collar to hold it. When you locked it down it literally left 2 indents from it.
If not, you may have to make something to jamb in there.

[justtorchit]

Yeah I did a full size one. The "locks" that hold the spanner collars have 2 "teeth" Ill call them. They are supposed to kind of bite into the collar and hold it from backing out. I tried to find a pic and cant find one that looks like the one I did.
If it has the "finger" style lock make sure that the collar isnt backwards. If it is the "finger" has nothing to lock into.
I wish I could find the pic, the lock was basically a 90 degree piece, it bolted to the cap flat, bent 90 degrees and was cut like 2 triangles that jabbed into the collar to hold it. When you locked it down it literally left 2 indents from it.
If not, you may have to make something to jamb in there.

ok. then that is exactly the same. but the 90 degree peice had like little nubs rather than spikes..... def, didnt dig into the collar........ must have been junk.

kinda just made me think though.... Like i said this rear end had been apart 2 times before i touched it. I wonder if the the last person to do the rear backed out the adjusters before loosening the retainer, rounded the spikes, and left nothing for them to bite into..... im willing to bet thats what happened.

[customcreationsllc]

the bearing caps were tight right?
I've never had them back off.
the Chrysler axle like to eat bearings I've done a bunch of them.
I would just put it back together and see how it is. since the pinion depth is already set you just need to set backlash.

I have 2 spanner wrenches make adjusting back lash much faster.

[ct67_72]

ok. then that is exactly the same. but the 90 degree peice had like little nubs rather than spikes..... def, didnt dig into the collar........ must have been junk.

kinda just made me think though.... Like i said this rear end had been apart 2 times before i touched it. I wonder if the the last person to do the rear backed out the adjusters before loosening the retainer, rounded the spikes, and left nothing for them to bite into..... im willing to bet thats what happened.

ah, there ya go. See if you can buy new lock tab things.