Diff goes boom...going on #4

My diff went boom on the freeway doing 70 mph driving to work this morning. It was my locked cryoed one. It was acting funky when I felt a jolt then 3 miles later I hear my diff imitating a blender. I will put in my diff from dana 60 H3.

After that I will never have another AAM-7 go in my truck. People that wheel with me know I wheel hard but for the abuse it gets I keep wheelspin down.

I have a dana 44 sitting in storage. Squeaky will get that most likely or if I kept the ifs it would be a retrofit gear able non piece of ****.

I was having some fluid leaking so I have had problems with the diff from day one. I won't blame this one of hard use but more of bad luck with that diff since September of 2013.

That sucks. Going solid axle now?

If u go solid I'd buy ur front rancho parts...is the price is right,and no one has claim it already lol

Sent From Someone Else's iPhone 'Cause I'm Too Broke To Own One.

Damn. Sorry to hear that Chris. So much for the cryo fix. Shouldn't have happened that soon.

Sent from my XT1080 using Tapataint

That was just a total disaster with that diff from day one. Sorry to hear that

Damn..that's a lot of diffs

Sorry to hear Chris.

Dude that blows! ****ty to hear your still having from diff issues!

Put in that diff from dana60h3 and start putting together your SAS gear in prep of #5


Sent from handheld smoke signal device

It's cool guys. We will see. I'm talking to 4speed now. I'm an IFS believer not an AAM7 believer lol

I still believe in the rancho spring over combo too. I can run with any rig with a similar tire size it's just that diff is a ticking time bomb. The one I regeared with my buddy from dana 60 h3 has no problems. Drives great. It's just this diff...

Like Zach said it's been this way since day 1 this diff was never meant to be in my truck.

I do carry tools on me. I'm off in a few hours and may pull the driveshaft just to avoid it destroying the driveshaft which can kill my t case

Pinion bearing is shot. Over an inch of play in the yoke...I have a video I'll post it up on YouTube and then here. Anyone on Instagram already saw it lol

That was doomed from the get go. No pinion seal we you finally got it back. An extra hole right next to the locker hole. Just be glad it didn't happen on the trail. Lol, those are fun times hearing all the noises in the trail. Two front diffs for you and a rear end and a half for me. But who's counting

Torres Fernando said:

If u go solid I'd buy ur front rancho parts...is the price is right,and no one has claim it already lol

Sent From Someone Else's iPhone 'Cause I'm Too Broke To Own One.

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Relax man.....sheesh. :whaa::roll::no:

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Sorry to hear about the explosion Chris. I know you'll get it patched up in no time.

That assembly you had built by the alleged "pro"...never would have made it more than 100 miles. I sort of eluded to that on post #92...
http://www.hummer4x4offroad.com/forum/showthread.php?6461-Ring-and-Pinion-help/page7&highlight=cryo
...perhaps I should have come right out and said it: You can't run ANY ring & pinion with .002" backlash.

Sorry for the b.s. this guy put you through. Live & learn I guess. Next time ...double check...triple check...whatever. Make sure its right before you run it.

So the root cause was? Bad parts? Crappy setup?


Mike

honestly, everything. Ready for a rant? Here it is!

This diff was a total nightmare from the get go. I had the gears cryoed and setup by that guy in lincoln, ca.

I sent my stuff out in september was told multiple times it would be at my doorstep by november 1st. I got it December 30th.

I then filled it with fluid to put it in and he never put a pinion seal in it. so I got a pinion seal and installed one. Drove it to work had bad vibrations. I also was shooting diff fluid out of the top because he had drilled a hole next to the predrilled hole for the e locker so I left the plug in the diff breather port and put the diff breather in there. Because of that I would shoot fluid out.

I pulled everything out got the locker that wasnt working to work and fixed the grinding issue which was a bad bearing. Then I put it in days before big bear trip (the entire time I was running my problem free cast iron diff I regeared to 4.56s that I got from dana 60 H3) so I pulled that diff put in the locked cryoed one and ran it to big bear spitting out fluid, kept topping it off, then I got the diff fluid to stop coming out of the diff breather but then had an axle seal leak. fixed the axle seal leak a few days ago and then fluid coming out the top again. I was going to close off the hole and put the breather back to the stock location. Before I had a chance to do that I was driving on the freeway I felt a clunk then it sounded like a blender/train crashing every time I hit the gas. I then pulled the driveshaft when I got home put it in 4 high lock to avoid destroying my driveshaft and t case. The yoke has so much play in it so the pinion bearing probably didnt get enough fluid burned itself up.

Its been a nightmare since day 1 and quite frankly I am done. That diff that exploded will never touch my truck again and to be honest I would never sell it trying to get rid of my problems and put them on someone else. My problem free CI diff will go in for the time being.

That diff is a paperweight now and will probably be thrown in the ****in garbage.

I love the IFS, I really do. I HATE THE AAM-7. My IFS is not the problem, with the spring over being locked up front and rear for a weekend my limitations were tires and strength of the AAM-7. I have no complaints with the torsion bars, steering rack, tie rods, hubs, halfshafts, etc. It all works just great but the AAM-7 sucks donkey dick. If my front diff could handle 37s and my 37s were not the duratracs I think I could start running the easier hammer trails, I already ran one, struggled a bit but got through. The toughness of a trail is subjective but my IFS has put me in places many people thought I couldnt go.

I then messaged Tech Tim on pirate he is the IFS dude on there. He along with bebe are IFS pioneers. I asked him what to do, he told me go with 37in MT/Rs get a clamshell IFS diff from a chevy 3500. Its a 9.5in ring gear. Thats Dana60 stuff right there. I reminded him it was driver drop and I am pass drop so then he told me I gotta machine one end and retube it. Right then and there I realized I am out of the picture. I cant machine things. I dont have the tools for that and I am sure as hell not letting anyone touch my H3 unless I can go to there shop and harass them on a daily basis seeing thats the only way I could get things done with this last diff. IFS tech is a few years away. Its kind of like 3 and 4 link suspensions. Only the hardcore buggy guys had them while everyone else had leaf springs but with time the price and difficulty of a link suspension came down to the DIYer for guys like me.

Right now IFS is out of reach for people like me. If I had my way I would leave my steering the same, my rancho kit the same, everything the same just put in a front diff that doesnt break, a front locker and a good set of 37s regear it to 5.13s and continue to smash every crossmember on squeaky into oblivion.

But unless some dude rings the doorbell and says my shop is 20 miles away and I will put a big diff into your front end the whole thing has to go.

So I have a beautiful locked up, built dana 44 pass drop sitting around. Ive been talking to 4speedfunk daily and as of now thats the plan. My current hangup is how to get to and from work during the swap. Squeaky is my daily driver. I dont have another car sitting around. My brother uses his jeep daily, my mom and dad use their cars daily and quite frankly I dont want a daily driver. I like driving squeaky daily.

And to finish off my rant I remember joining up on the forums back in 2010 saying I needed a solid axle to wheel, I was brain washed by the jeep guys. Cbetts told me come out and wheel with us. From that day one I basically became anti solid axle showing people you can do tough trails with a factory IFS. It works when its working. when its not working its the AAM-7s fault.

Sorry I sounded so bitter, I dont think I am a bitter person but when your swapping out AAM-7s every 2 weeks since september you would feel the same way.

-Chris

4speedfunk said:

That assembly you had built by the alleged "pro"...never would have made it more than 100 miles. I sort of eluded to that on post #92...
http://www.hummer4x4offroad.com/forum/showthread.php?6461-Ring-and-Pinion-help/page7&highlight=cryo
...perhaps I should have come right out and said it: You can't run ANY ring & pinion with .002" backlash.

Sorry for the b.s. this guy put you through. Live & learn I guess. Next time ...double check...triple check...whatever. Make sure its right before you run it.

Click to expand...

Amen, He set the diff up tight for sure. So when it did deflect it wouldnt fling chips of my pinion gear all over the place.

The post above this one sums it all up.

Sorry the lessons learned always seem to come with a price tag. Chris if I am around when you are working on your truck I am happy to come up and spend a weekend helping you get it back on the road.

I read through the other thread about your issues with the differential. I'm sorry, that sucks. I had the same kind of issues with 1320gforce... what a bunch of monkeys - in my loft I have a nearly brand new GTO differential with a all-gear limited slip. It howls like a banshee - 3x it went back and forth to get fixed... in the end I bought a junkyard differential and stuffed it in the car.... then sold it (the guy who bought it hates me, I'm sure, that car was a POS).

I have a local guy that does stuff that I either don't have time for or stuff I can't do - but he's not perfect either; though for this stuff, gears, he knows his stuff because the front differential is still working. Honestly, though, it wasn't great choosing on my part, I simply got lucky and found a former GM tech who now owns a shop.

As for machining, you're in Southern Cali, with the aerospace industry, there must be a decent shop that can do the machining for you on those shafts - really, I looked at doing something similar and it really doesn't appear to be rocket science

and finally, I thought cryo hardening was simply a surface treatment for flat-tappet cams.... from what I understand, it doesn't make the parts any tougher, it simply provides a better surface....

Cryo treatment from what I understand is the heating and cooling of parts and makes them tougher and harder but if you go too far they will become brittle. I'm no expert on the process but have read of many people who were racing and were killing R&Ps every race but after cryoing they would last a whole season.

My concern is if I add 37s and a diff to regear and handle it what would be next.

I look forward to the future when badass KOH type ifs hits the average DIYer.

Dave I appreciate the offer and will take you up on that! It's been too long! I haven't seen you in over a year

Chris I am traveling the next three weeks but after that I will make the drive, just let me know.

We are all waiting on you Chris to come up with a bolt in diff we can regear! I haven't even broke a tierod or halfshaft yet (my cautious wheeling style). But would be $$ in for a diff I can regear, go 4x4 knowing I won't break it!


Mike

poncho1965 said:

We are all waiting on you Chris to come up with a bolt in diff we can regear! I haven't even broke a tierod or halfshaft yet (my cautious wheeling style). But would be $$ in for a diff I can regear, go 4x4 knowing I won't break it!


Mike

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I am going to the junkyard this monday. Its half off weekend. I may pull an 8.8 IRS just to test fit and see if it actually fits probably wont do much other then see if it fits.

I am torn, I love the IFS. I want the IFS but the technology isnt there for a DIYer.

Geometry isnt easily accessible yet. I wish you guys went to the king of the hammers. IFS KICKS ASS! I personally felt the IFS outperformed every solid axle rig out there, in the rocks and the desert. They climbed up the gnarliest rocks with ease, faster and easier then the SA buggies. Its just not for a DIYer yet. Flex, yep they had it. Strength, yea they had that too.

The problem with IFS is that you want it center mounted, so you can have long a arms long CV's a narrow diff. The buggies are rear engine, they have pass drop or driver drop rear axles and centered front diffs. Its all backwards and no oil pan in the way of center mounting it. For a regular 4x4 you almost want a dry sump oil pan to give more clearance. The technology wasnt there 5 years ago, Shannon Campbell was considered nuts for running IFS, yet he won. Now IFS buggies are popping up all over. Give it another 5 years and they may hit the DIY level.

If it wasnt a daily driver I would entertain the idea of a one off IFS, I am almost ashamed. I love challenges, I like being unique and avoid being typical and going the same as everyone else (in terms of every ifs rig goes SAS.) If I could I would put squeaky down like 4speedfunk, bebe and recon did. Every problem you hit a problem you brainstorm, think, and tackle. I dont have that time. I have a window that is to get squeaky on the road ASAP. It goes to work everyday, it goes to school everyday too.

I am on an emotional roller coaster with my plans. A month ago I wasnt sure on the SAS, then my diff blows and Im like **** YEA! I cant wait for a SAS **** the AAM-7, then I flip flop back and forth. I think the biggest thing for me is giving up I hate giving up, you know the corny saying "when the going gets tough the tough get going" if I give up the IFS I just gave up. I said I needed a SAS to wheel 4 years ago. Craig showed me that wasnt necessary. Then I went around going hating on the solid axle, even got a "flex is overrated sticker" lol now I just give up on my beloved IFS. My stance still stands, I love IFS I hate the AAM-7. Its a piece of complete ****.

Chris, was this one the CI diff I gave you, or a different one?

Really stinks how many times this has been danced around but there's just no one simple answer that works.

Really hoped that the CI, with a solid build, ESPECIALLY with cryo'd gears would have been bomber for you.

06 H3 said:

Cryo treatment from what I understand is the heating and cooling of parts and makes them tougher and harder but if you go too far they will become brittle. I'm no expert on the process but have read of many people who were racing and were killing R&Ps every race but after cryoing they would last a whole season.

My concern is if I add 37s and a diff to regear and handle it what would be next.

I look forward to the future when badass KOH type ifs hits the average DIYer.

Dave I appreciate the offer and will take you up on that! It's been too long! I haven't seen you in over a year

Click to expand...

when a part is forged, it's like wadding up a piece of paper the paper is stronger because it's denser, but the structure inside that paper isn't as strong as it could be because the outside molecules are squished together and the inside is closer to its original dimensions. When a part is cast, the molecules stay equidistant in relationship to each other, thus its strength is the strength of the material. Heat treating (and cryo treating) attempts to regain some of the lost strength that is caused by the squishing (technical term ) the metal together like paper - what it does is bring the material up to almost-melting temps and allows the molecules to get back to equidistant spacing. That is stronger, and retains some of the plasticity of the steel. Cryo treatment is different because it work-hardens the material by freezing it - when you bring the steel to super-low temps, it causes the molecules to push against each other, thus work-hardening the material - they only put the material in the fluid for a set time to limit the depth of the material. Picture baking a cake - if you pull it out too soon, the inside is still moist, too late, the outside is crunch hard.

The advantage of work hardening the surface is the parts have less friction, thus less heat. Less heat means longer life and better dimensional stability. The disadvantage is if you do it wrong, the part becomes brittle - without lab analysis, I suspect that's what happened to your part. They cooled it too long, making the surface very brittle and losing all the plasticity of the forging/heat treatment process. It's not a rookie move, the science of cryo treating is a very exacting science, and you can't treat a part using analogy.... example, you treat a camshaft for 10 minutes - by experience you know that gives you the best hardness without losing the ability of the cam to flex under load.. thus, not snapping like a toothpick.

While I understand your frustration with the CI differential, when you said that your half-shafts have survived longer - you made me suspect that all is not well within your differential, thus making it more likely to break. Back in the early 60s, my dad used to drag race a 39 Chev coupe at Lions - the rear differentials they used were smaller than what a rwd corolla had... and they survived because the people who drove the cars knew their weakness....

please forgive the shortness of the response, there is a lot to metallurgy ... I've been playing with this stuff to make my 455 Buick stay together under 900 hp of boost... on a cast crank.

backcountryislife said:

Chris, was this one the CI diff I gave you, or a different one?

Really stinks how many times this has been danced around but there's just no one simple answer that works.

Really hoped that the CI, with a solid build, ESPECIALLY with cryo'd gears would have been bomber for you.

Click to expand...

It is your diff, I dont believe it was the diff or cryoed gears but more of the setup. It was setup very very tight allowing a ton of heat.

SuperBuickGuy said:

when a part is forged, it's like wadding up a piece of paper the paper is stronger because it's denser, but the structure inside that paper isn't as strong as it could be because the outside molecules are squished together and the inside is closer to its original dimensions. When a part is cast, the molecules stay equidistant in relationship to each other, thus its strength is the strength of the material. Heat treating (and cryo treating) attempts to regain some of the lost strength that is caused by the squishing (technical term ) the metal together like paper - what it does is bring the material up to almost-melting temps and allows the molecules to get back to equidistant spacing. That is stronger, and retains some of the plasticity of the steel. Cryo treatment is different because it work-hardens the material by freezing it - when you bring the steel to super-low temps, it causes the molecules to push against each other, thus work-hardening the material - they only put the material in the fluid for a set time to limit the depth of the material. Picture baking a cake - if you pull it out too soon, the inside is still moist, too late, the outside is crunch hard.

The advantage of work hardening the surface is the parts have less friction, thus less heat. Less heat means longer life and better dimensional stability. The disadvantage is if you do it wrong, the part becomes brittle - without lab analysis, I suspect that's what happened to your part. They cooled it too long, making the surface very brittle and losing all the plasticity of the forging/heat treatment process. It's not a rookie move, the science of cryo treating is a very exacting science, and you can't treat a part using analogy.... example, you treat a camshaft for 10 minutes - by experience you know that gives you the best hardness without losing the ability of the cam to flex under load.. thus, not snapping like a toothpick.

While I understand your frustration with the CI differential, when you said that your half-shafts have survived longer - you made me suspect that all is not well within your differential, thus making it more likely to break. Back in the early 60s, my dad used to drag race a 39 Chev coupe at Lions - the rear differentials they used were smaller than what a rwd corolla had... and they survived because the people who drove the cars knew their weakness....

please forgive the shortness of the response, there is a lot to metallurgy ... I've been playing with this stuff to make my 455 Buick stay together under 900 hp of boost... on a cast crank.

Click to expand...

That is a great analogy. I still dont think it as the cryo gears but the setup. It took a lot of force just to move the pinion. It was set up with very very tight tolerances. I think the problem was the setup.

As for driving style I dont believe my right foot is the problem. I was the first to admit my driving style was subpar in the beginning. I broke my halfshaft and front diff the first time from bouncing the crap out it. I then went on a few runs with Cbetts and learned the right foot needs to stay out of it, I shut up and listened to the guys that knew best. I wheeled for almost 4 years with no breakage at all and I ran some difficult trails with that. I then trashed my pinion on the 2nd diff back in september. I ran a ton of trails in that 4 year period, moab twice, Last chance canyon atleast 7-8 times, local trails over 40 times, big bear trails 6-7 times, at the end of each year I made a list of the trails I ran and I was out on the trail every 2 weeks or so. I never broke a thing. Then in september it finally gave out. I then dealt with this issue and had to pull this problematic diff and put it a CI diff I regeared myself and had zero issues on a few trails I did run with it including Clawhammer at Johnson Valley. Then I swapped out that diff for this one again and on the freeway doing 70 I felt a clunk then grinding. I dont think anyone can possibly say that driving style was my fault on the 3rd one. So overall I would say the 1st diff was my fault, the 2nd diff was just a ticking time bomb (took roughly 4 years) because of the trails I was running and the amount of trails and the 3rd one was diff setup error. So if I put this other CI diff back in I say give it a few years and I will be back in the same position. All AAM-7s are ticking time bombs.