Surging vibration (this ended very badly) -new pics

HEY Mototrooper - I got so excited I sent that dude an email before I looked ....and then sadly realized his is a 75 - so its a 4 speed, (and he was only 40 miles away) would have to make too many changes DRAT :(

HEY Roger - sounds like a very generous offer to me!! Let me get a bit further into my train wreck here, and I will reach out to you once I have a handle on how this is going to play out..
 
Cougar72 said:
HEY Roger - sounds like a very generous offer to me!! Let me get a bit further into my train wreck here, and I will reach out to you once I have a handle on how this is going to play out..
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Just let me know. Glad to help.
 
I also have a supposedly complete box of 5 speed transmission parts that came with a parts car. The story goes, all the internals to the gearbox were good, but the case was cracked. If you need parts, I'll see if I can find a match. You pay shipping and it's yours.

Pete
 
Cougar72 said:
HOWDY ALL, I have an update... and its not a pleasant one.

1. I removed the axles and fully cleaned and disassembled the CV's I noted their original position (driver/passenger & Inboard/Outboard)
2. I fully cleaned and inspected them. There was only one spot on one of the races that had a very small wear dent
3. I reassembled all of them and switched them from inboard to outboard AND ALSO I switched them from driver to passenger - this completely switched up their rotation and pressure spots and angles when under torque as all 4 of them are the same part. I used proper CV grease and new boots and new proper hex bolts to attach the axles to all the stubs.
4. I went for some test drives ( total of 50 miles) and although it seemed that it made a difference ( 30-40% change for the better??) - the issue was not fully corrected.
5. I sadly parked the car for a few days and pondered my existence
6. After a week of pondering.... I decided that I would now adjust the car back up to its original height (or even higher as a test) - My car is what today they call "slammed" as I have adjustable coil overs and they are set with the car super low to the ground - to the point that there is almost zero clearance for wheels and like only 3 inches clearance from its belly to the asphault. My thought was that it would straighten out the axles a bit and reduce the acute angles on the CV's and thus reduce the movement and positions of the ball cages as the axle rotates.
7. My plan was to go on a short well known drive and carefully notate how much of the surge/shake was occurring and where and then come back and adjust my coil-overs... and do the exact drive again to see if there was any noticeable change.

This is where everything went very wrong - very very wrong.



While heading down the driveway for the pre-adjustment test drive - at 8 MPH coasting in 1st gear the tranny exploded - YEP, exploded!!!. the whole differential area blew out the case top and bottom. You can grab the speedo cable and pull it up into your hand and it has a 6inch piece of the case still attached to it. and 100 bucks worth of redline MTD painted my driveway with a 4 inch wide stripe as I coasted to a stop - I suspect this new "graffiti" on my driveway will continue to remind me of this unpleasantness (and worse remind my wife) for quite a long time.

I will start a thread related to the tranny with some pictures at some point here soon with additional descriptions and my plans to remediate.

I talked to Matt at MWB and he does not believe my work on the axles OR the jounce/shudder/surge was related to the tranny exploding - but it was not conclusive. He speculated that a bolt backed out of the differential ring gear- <shrug?>and bound up / blew up. Matt did mention that he too has experienced the shudder I describe, and that I was on the right path to solve and troubleshoot it. and the next steps would be to more closely inspect motor mounts

So in summary, I don't know yet what will resolve my shuddering issue noted in this thread - AS I NOW HAVE BIGGER PROBLEMS TO FRY..... (crying)
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Cougar,

Man, just reading your post was painful. I can't imagine how you must feel after all that work. You have my heartfelt sympathy. My first thought is that it would be an AMAZING coincidence for the gearbox to explode just then and have absolutely nothing to do with the work performed. I am sure its possible but I'm just not a big believer in coincidence. I guess a gear box tear down might tell the tale assuming there's enough left to autopsy.

Hang in there and don't get discouraged - the worse the problem, the greater the sense of accomplishment when its fixed!

Ed
 
Please post pics when you take it apart. I'm curious as to whether the CV's are similar to the design used by Volvo for the AWD fore/aft driveshaft -

x70AWDcomponents0022.jpg


x70AWDcomponents0019.jpg


- The problem with these is that they appear symmetrical, but in fact only go back together ONE way for proper articulation - I found that I had to mark all three parts relative to one another before disassembly. Although they do go physically go back together in more than one orientation, they will lock up under any load if incorrectly assembled. I found that out the hard way.

Either way, it's hard to see how that could break the diff casing....
 
It would be interesting to see pictures of the damage and then maybe a thought on what happened to cause it.

(Are we thinking this is the cause of the Surging? or think it was just a fluke of timing?
 
Coincidences happen, but not often, by definition. The disintegration of the box is odd enough, but the rather violent surging that you described is just as odd. Two oddities together seems very odd indeed.
 
Update ... I got my tranny out, and I can see what exploded inside.

I have ordered a core from Matt (MwB) along with tranny seal kit and new clutch kit.

I just delivered both the core and my old exploded unit to a local tranny shop who knows what to do they specialize in manual gearboxes from Porsche and VW and Audi... We're basically going to Frankenstein my two together... With any luck the core from MwB will be in acceptable shape and it will not need much.

I see your offers: Roger" & "Pete" and depending on what we find -I may contact you and see if you have parts. Some things are different from year to year in the 5 speeds... So we will see how this goes with matching to your 81. I don't actually know what year my new core is (shrug?)

I elected to not crack it open myself as time,tools, and personal skill might have impeded success. I also decided that it took me a bit of time to get the blown unit out, and I jut did not want to shotgun in this core unit only to find it has problems.

Trying to post pics now
 
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The bearing carrier split apart

Yep that's the gaping hole on the TOP side where the speedo normal connects. if you look close you can see the hole on the bottom side also and the cracks all the way around the case

Notice my fresh grease from my repacked CV's there as well....sigh!

The CV's were both smooth and the axles were not bound in any way...they had normal side to side play (axle direction) as well, to acomodate suspension jounce compression. And I rotated the wheels many times before the test drive and they spun effortlessly. I had already gone on a previous 5 mile test as well.... Is it just coincidence that the tranny blew? It's kinda wierd as I just did the axles..(sigh).

I am pretty sure that the cv cages went together properly, I did have one inside out in my hand on the bench, no articulation at all .. Poped apart and flipped it fixed it. Anyone here think I still may have something haywire with them -now is the time to let me know before I put in the new tranny.

Anyone think that the original problem of the bounce/jounce/ surge that started this thread could ACTUALLY have been that crack in the Differential bearing rack?

I also just realized you can see orange permatex oozed from the main seal...whoever was in there...it was not me!
 
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You can see it's even cracked on the opposite side

And looking at that ring gear bolt and the ring gear itself...that might have been the point of contact for the slag to bind up and blow thru the case
 
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I have been told here and also by Matt to check my lower engine/tranny mount.(possible cause of surge/jounce)... That piece of rubber is on the floor of my shop now as part of the tranny pull

So what am I looking for? It seems pretty Ok... Not too saggy. It has a few mm of side bulge due to compression (granted it is no longer under load)

Matt also said that only used ones are available so they might not be better than mine....

Yes the cv hubs are close to the cross member down there, but they don't look like they have ever touched or rubbed due to sagging with this mount.
 
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Cougar72 said:
I have been told here and also by Matt to check my lower engine/tranny mount.(possible cause of surge/jounce)... That piece of rubber is on the floor of my shop now as part of the tranny pull

Matt also said that only used ones are available so they might not be better than mine....
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Doug (RX1900) had a batch of new mounts manufactured, see this post.
 
I can recommend the new mounts offered by Doug (RX1900) though he may not have any more unfortunately.
 
That's some serious carnage! Curious to know what would cause such a load on the spider gears/shaft (diff) casing itself. Maybe more pics once it's apart, if the shop is willing or will save all the damaged bits for you...
 
I was just reading through this thread and noticed that you had mentioned:

My car is what today they call "slammed" as I have adjustable coil overs and they are set with the car super low to the ground - to the point that there is almost zero clearance for wheels and like only 3 inches clearance from its belly to the asphault.

I'm wondering whether this may be the initiator of the problems you have experienced? Possibly the angle of the driveshafts was reduced to the point where you were putting too much strain on the CV joints and diff?

Just an idea...

Dom.
 
Dominic...

I was curious of the angles myself. I was planning two tests, to play with these angles, and look for a change in my original problem... and I only got one done.

Test one was to raise, and and also lower (compress) the back of the car and confirm that the driveshafts always had some lateral slop. It seemed that they always did. I also inspected the insides of my stub axles while they were out to see if the spline ends were hitting the insides of the cups..all seemed fine.

Test two was going to be to take the coil overs and spin them all the up way to "high load" thus raising the suspension up. But it was during the pre adjustment test drive that the tranny blew...so I never got the chance to see if that made a difference with the original problem. I may still put it up a bit when I get the new tranny in.

I am left still wondering if the angles, or the clean and repack I performed of the cv axles led to some sort of pressure or binding.....??? (Shrug). And, a little afraid that if so, it could nuke my new tranny.

I have to think that others have lowered their cars some. It is still within the original jounce range of a stock suspension - albeit sitting lower when static. ....shrug?
 
I think Rapunzell has mentioned before, the minimum height for the rear of the car is when the driveshafts are level to the ground...
 
Ideally, as Jefco said you want the rear axles to be level with the ground. I personally have never seen something like this before. I don't see how the angle of the axles would have any bearing (excuse the pun) on this.
It really looks like you had either a part which was already failing, or had failed. However, as I think about this I did have a similar issue with my car once where under a heavy turn, the rear of the car made contact with the rear tires temporarily locking them up. This stripped my third gear completely. If the PO had it really slammed, and was running wide tires there is a chance they could have caused some damage to the transmission. the other example of this would be a drag strip launch, but usually the drive shafts go long before the transmission does. Sorry for your trouble. But, just to keep you happy I had to take the transmission out of my car three times in one day when I first started learning about them. First time I had 1st and 2nd locked. Second time, reverse was upside down... Good times!
 
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