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1980, L-48, manual trans, 48k miles: So, I was driving down the highway at 65mph and my drive shaft separate from the transmission....no warning, just a loud bang. Fortunately, I didn't get catapulted. Surveying the damage...extensive! u-joint, ground wire, transmission speedo cable, bracket, etc. Biggest issue: The transmission casing cracked and separated at the neck. Do I need to get a replacement or can I repair the case? Any thoughts on what could've cause this? Thanks in advance!
Thanks for the quick reply. Yes, I think you are correct. See pics below. Now my question is: What could have caused this? The transmission spline seems to rotate normally, and so does the differential.
My guess is the straps on the yoke loosened up and the U-joint liberated itself from the yoke and went for a wild ride.
That’s some serious carnage....
I hope it's as simple a cause as that. I'm concerned that my differential could be the source of the problem. It seems harder to turn the rear wheels than it should be. What's the best way to inspect the differential on the car with no drive train?
I hope it's as simple a cause as that. I'm concerned that my differential could be the source of the problem. It seems harder to turn the rear wheels than it should be. What's the best way to inspect the differential on the car with no drive train?
If the rear of the car is off of the ground and the rear wheels are hanging down, you will not be able to turn the wheels around. You need to support the wheels at the trailing arms in order to get them to turn. Hanging all the way down, the angle is too severe for the u-joints to rotate fully. Good luck.
Thx, Bryan. I was able to determine that the differential feels fine. However, I noticed that the leaf spring has been scraping against the inside of the wheel ever so slightly. I haven't heard or felt it, but it scraped into the wheel pretty good, so it has been happening for awhile. Could that have created a vibration in the drive shaft which might have led to the yoke/u-joint giving out?
It gets worse! Check out the pictures below. Damage to the transmission casing where it bolts to the bell housing. Also, the bell housing is cracked. Looking inside, it appears the flywheel is scuffed up. The crap is getting deep!
Looking inside bell housing...flywheel is scuffed up. How'd that happen? Cracked bell housing at top. Cracked bell housing all around. Bottom transmission/bell housing bolt. Cracked! Ouch.
Thx, Bryan. I was able to determine that the differential feels fine. However, I noticed that the leaf spring has been scraping against the inside of the wheel ever so slightly. I haven't heard or felt it, but it scraped into the wheel pretty good, so it has been happening for awhile. Could that have created a vibration in the drive shaft which might have led to the yoke/u-joint giving out?
I am no expert in these matters, but I cannot imagine a scenario where that could have happened. Given the pictures that you just posted of the Trans case and bell housing, I would think that you had some type of catastrophic failure further forward in the driveline and the driveshaft was the last victim. Actually, looks like your battery cable and parking brake cable may have technically been the last. The damage to the case and bellhousing is pretty dramatic. Looks to me like the whole thing twisted and the trans tail and driveshaft were the exit point for that rotational energy. Again, I'm not an expert but it is difficult to imagine that all of that occurred as a result of your driveshaft letting go.
Thx, Bryan. I suspect it is something further forward, like in the flywheel area. But, after the driveshaft gave out on the highway, I was able start the car and the engine sounded normal, so I don't think anything seized in the flywheel or transmission. I suspect something caused a vibration, which hit a harmonic frequency really fast, and then the the blow-up. I need to figure out what the initial cause was. I'm pulling the transmission now. I'll keep you posted on what I see. I very much appreciate your thoughts and insights. I have a brother who is a GM certified mechanic, but he's not very responsive. :-(.
Ok, got it all apart. Below are pictures of the damaged components. I still don't know the cause of all of this carnage. I would be grateful for any help and ideas you guys could share. I'm gonna start purchasing replacement parts, but I don't want to put anything back together until I have a solid idea on the cause. The last thing I want is to spend the time and money on getting it back together only to have the same thing happen again.
Two of the bolt tabs cracked off.
Cracked and separate from the housing.
Bell housing looks fine inside, except for the cracks!
The throwout bearing seems fine.
The pilot bushing looks good.
The flywheel has some loss of paint in a few areas indicating some rubbing going on. Does this look out of the ordinary? Could this be the cause of vibration?
The cover of the bell housing is bent. Not sure if this might indicate anything.
WOW... Just wow!
That’s some amazing damage.
Looking at the trans, it almost looks like it just locked up at speed and tried to spin itself around in place but the yoke breaking prevented it.
When this happened, did the engine continue to run or did it stall?
Have you opened the side cover of the trans to see if there is any carnage inside?
Crazy..
The engine continued to run, until I shut it down. I was able to restart it and ran through the gears, everything appeared normal except that there was no forward movement. I haven't opened up the transmission yet, but I don't think it locked up. My brother, A GM certified mechanic for over 25 years, thinks the u-joint gave out.
Opened the transmission this morning before church...curiosity is a powerful thing. :-) Good news: Doesn't appear to be damage inside the transmission (see pictures). So, it looks like the source of the problem is the u-joint failure. Please let me know your thoughts, ideas, etc. Thanks.
....However, I noticed that the leaf spring has been scraping against the inside of the wheel ever so slightly. I haven't heard or felt it, but it scraped into the wheel pretty good, so it has been happening for awhile.
Any pictures of this area? Are you sure nothing grabbed back there?
The frt bearing support break often. Replacement not expensive.
Did you say the bellhousing has cracks? Some may look like cracks but ar just casting defects/imperfections. They look like spider webs sometimes.
Transmission looks nice and clean inside. If you don’t mind the effort, might be a good tie to change the fluid and check the differential, just to be sure that wasn’t the cause.
I would suggest getting yourself a drive shaft loop if you don’t find a definitive cause. Cheap insurance if it happens again. You got lucky this time but catapulting doesn’t sound like a lot of fun, though I don’t think it’s easy for the drive shaft to drop that far.
Any pictures of this area? Are you sure nothing grabbed back there?
ignatz, I ruled this out as a possible cause. The scraping wasn't as deep as I thought...just scraped away the dirt, really. I determined that this scraping happened when I had the wheels up and was turning the wheels to check the differential. With the wheels raised up, the leaf spring was rubbing against the wheel as I turned the drive shaft. Picture below.
The frt bearing support break often. Replacement not expensive.
Did you say the bellhousing has cracks? Some may look like cracks but ar just casting defects/imperfections. They look like spider webs sometimes.
Yes, the bell housing is definitely cracked in several locations.
When you say the bearing support breaks often and the fix isn't expensive, what is the fix? Transferring transmission innards to a new main case? Or, do you mean something else? Looking for options, if any. Thanks.
06-01-2018, 11:53 AM
C3 manual transmission case damage
