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View Full Version : Diagnosing a drivetrain noise -- what would you have done?


Hulk
04-04-2009, 12:26 AM
Monday evening, we got back to Denver from Telluride. The first couple of hours of the trip were the worst. From Telluride to Montrose, we drove through snow, ice, rain -- and we were behind a truck that sprayed us with road scum the entire way.

The ice was so thick on my 80 that it looked like an old boat covered with ocean life. It was wretched.

When we arrived back in Denver, we drove straight to the car wash. I tipped the guy pre-spraying the cars, and he spent 10 minutes trying to get the ice off. Then we went thru the car wash. On the other end, he looked at the car and waved us to go back to the start. Another 5 minutes of pre-wash blasting, then the full car wash again. By the end of this, the ice was mostly off, but it still hung from the rear lower control arms 6 inches thick.

The next day, I drove it to work and noticed a "squeak." My first thought was that my power steering might finally be seizing up -- I've been keeping an ear tuned to it lately. Or maybe the water pump. But no -- the noise seemed to be non-engine related. When I revved the engine at a dead stop, no squeak. When I started moving, the squeak re-appeared. It increased with speed, so I thought "drivetrain."

Specifically, I though U-Joints. I've replaced them on numerous vehicles going back to my 1966 GTO that I owned as a teenager. It just seemed right to me.

So Wednesday morning, I took off a few hours from work and tried to diagnose the problem. My front shaft is a double cardan Slee shaft, which is about 11 months old. I haven't greased it since I installed it. My rear shaft is one that I purchased from Bikeman a few months back and installed very recently.

I grabbed my older grease gun with a full length lever handle and a long rigid metal nozzle, and managed to get it on one zerk. The rest were impossible to get to with my grease gun without removing the shafts. And I was almost out of grease anyway (this was leftover from doing the front axle service -- thanks again, Hants!).

So I remembered a thread on this forum where Romer was discussing an impossible-to-reach zerk and Robbie recommended a Napa grease gun. I didn't look for the thread; I just headed over to Napa and bought this grease gun (http://www.napaonline.com/NOLPPSE/%28S%28smvftu55sujhsyzkc1g5er55%29%29/Detail.aspx?R=BK_7151230_0006381963). It has a pistol lever (much easier for one-handed operation) and a flexible rubber hose.

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I managed to re-grease all the U-Joints on my front Slee shaft and the rear U-Joint on the rear new shaft (the front U-Joint zerk on the rear shaft was still impossible to get to).

I figured that if a U-Joint was indeed the culprit, forcing in a bunch of new grease would at least change the sound of the squeak, and help me identify the problem.

The result? The squeak remained, and sounded exactly the same.

Hulk
04-04-2009, 12:38 AM
OK, so I thought: it's a different problem. A wheel bearing? A loose brake part? Nothing made sense to me.

Here's where I would like to hear what you all would have done.

I considered putting my all-time 4WD 80 up on four jack stands, starting it up, putting it in gear, and listen for where the sound was coming from. Maybe I would need to crawl under the car, spinning driveshafts and all, to find the problem part.

This did not seem out of the question, but it seemed risky. I have no doubt that I would have done this 10 years ago, but I have grown more cautious in my old age. I have two kids that I would like to stay alive for and watch grow up. I didn't want my Cruiser to fall off a jack stand while revving a few thousand RMPs with the tires spinning, and me underneath it.

I drove over to the nearby Grease Monkey and Midas to see if they had a lift they could put it on, start it up, and put it in drive to diagnose the problem. Neither had a lift capable of doing this with my big Cruiser.

Finally, I took it over to Toy Car Care, a local Toyota repair shop that I have had great experience with. They drove it a bit, then put it on their hoist, ran the vehicle, and diagnosed the problem: front Slee driveshaft, in the double cardan end. Took them half an hour and they charged me $48.

I'm not complaining about Toy Car Care in the least -- they did a great job, and they weren't surprised at all when I didn't want them to do the repair for me. I'll pull the shaft tomorrow and replace the U-Joints myself. No problem.

Here's my question: how would you guys, who are more experienced mechanics, have diagnosed this problem? Would you have put the Cruiser on four jackstands and found the problem in the way that I was scared to do?

Beater
04-04-2009, 07:29 AM
UM, NO... a lift is infinitely safer IMHO. Not too mention faster, easier, and less stressful. I am so lazy these days that I don't even do my own u-joints... I combine the lift time with another job that I don't have time for, and send them over to the driveline shop..

DaveInDenver
04-04-2009, 07:33 AM
I've done the 4 jack stand thing and let the truck idle in gear. Dangerous? Probably, but I like being a scofflaw living on the edge, man. No one tells The Dave what to do.

RockRunner
04-05-2009, 06:50 PM
I have done it with my 4Runner but then again if it did come of the jack stands it would not hit me. It is high enough that it would not crush me:p:

Now with my GMCI would not do that, way to low to the ground.:(

Hulk
04-06-2009, 12:21 PM
I pulled the shaft yesterday. Sure enough, the double cardan end is bound up and squeaky. Now I'm glad I installed that center diff lock switch so I can still drive my 80 with only the rear shaft installed.

Is there a trick to getting these U-Joints out? I started trying to get one out last night, but it seems to stop before one of the caps is all the way out of the hole.

timmbuck2
04-06-2009, 12:41 PM
I pulled the shaft yesterday. Sure enough, the double cardan end is bound up and squeaky. Now I'm glad I installed that center diff lock switch so I can still drive my 80 with only the rear shaft installed.

Is there a trick to getting these U-Joints out? I started trying to get one out last night, but it seems to stop before one of the caps is all the way out of the hole.

I took mine to Englewood Driveshaft. :) Was not worth my time...not that I have any time....

Rzeppa
04-06-2009, 09:00 PM
I pulled the shaft yesterday. Sure enough, the double cardan end is bound up and squeaky. Now I'm glad I installed that center diff lock switch so I can still drive my 80 with only the rear shaft installed.

Is there a trick to getting these U-Joints out? I started trying to get one out last night, but it seems to stop before one of the caps is all the way out of the hole.

Whenever I change u-joints I keep an old bearing cap around to drive out the next one. BFH usually works. Christo has an awesome 100,000 pound press that I bet would work. Occasionally I will warm up the yoke with a torch to expand it. I hate u-joint work almost as much as I hate exhaust work.

On the 4 jackstand question, yeah, I'd probably do it. My kids are already grown up :-)