M813 drive train noise / clatter

[kylenobes]

Hello All,

Last night I was driving my 71 m813 around town and during braking it made a "thump" sound under the floor, and then I heard gear clatter/grinding for about 3 or 4 seconds. I pushed the clutch in and the noise continued until I slowed down a bit and then it went away.

A few miles later I was cruising around 35 mph in 4th gear and it did it again. This time it just started to make the noise out of nowhere for about 4 or 5 seconds, and again went away (after I slowed down a lot).

I babied it home and had no other problems.


The noise is not really a grinding noise, but it sounds like a gear that is not engaged properly (like when you're trying to put a truck in gear while moving, etc.). Hard to explain.

I have read about TC actuator and also the air valves on the TC? I am a little stumped. Any help or advice would be great.

 

[kylenobes]

One other thing... when it happened the second time I felt the vehicle sway a little bit and feel a little "squirly" for a second.

 

[kylenobes]

I forgot to mention... when it first happened I was braking hard and it felt like I locked one of the rear wheels up for a second. Could it be a sprag issue?

 

[R Racing]

Was it happening in a turn? Walker beam rears make tons of noise in corners until they run straight a while.

 

[R Racing]

I have seen mine stagger left to right a good 4 inches or more.

 

[Jeepsinker]

Pull the jackshaft and run the transmission through the gears with the engine running and see if you can recreate the noise. If not, reinstall the jackshaft, unbolt the front and rear driveshafts from the transfer case and try again. This will tell you if it is in the transmission or transfer case.

 

[doghead]

Look at your torque rods and be sure they are all good.

When and axle moves from a TR failure, the splines on the driveshaft can pull out and grind as you describe.

 

[1958 M274]

Check your high/low shift lever for the transfer case to be sure it's adjusted properly and engaging fully. I was driving my first M816 out on the road for the first time and had an issue similar to yours. I had driven it a few miles around in the yard in all the gears and everything seemed well. About a mile down the road as I started going up a good sized hill under load there was a thump followed by awful noises. I pushed in the clutch and after a second or two the noise slowed and went away. I coasted to a stop and got out, looking for parts laying in the road! (Not a good feeling!) I couldn't find anything wrong and everything in the truck seemed to work so I eased out again. A few minutes later it did it again. This time I noticed out of the corner of my eye that the transfer case lever was sliding out of gear under load, grinding, and when I pushed in the clutch releasing the load it would drop back into gear. The shift lever was adjusted properly and engaging fully, it was an internal problem.

 

[kylenobes]

Wow thanks for all the advice!

It happened while I was driving straight. I was coming up to a stop and hit the brakes too hard and felt it locked up the rear & did a slight hop (for a second) and then that's when the noise came. Sounded either like something disengaged or something was trying to engage but couldnt due to being in motion. As I slowed down the frequency of the clatter also slowed down.

The second time it did it was a few miles later, again while driving in a straight, except this time I was not braking hard and only cruising around 28-30 mph with light throttle.


I will play with the hi/lo shifter first and and take it slowly down the road & back and see what happens.

 

[kylenobes]

Check your high/low shift lever for the transfer case to be sure it's adjusted properly and engaging fully. I was driving my first M816 out on the road for the first time and had an issue similar to yours. I had driven it a few miles around in the yard in all the gears and everything seemed well. About a mile down the road as I started going up a good sized hill under load there was a thump followed by awful noises. I pushed in the clutch and after a second or two the noise slowed and went away. I coasted to a stop and got out, looking for parts laying in the road! (Not a good feeling!) I couldn't find anything wrong and everything in the truck seemed to work so I eased out again. A few minutes later it did it again. This time I noticed out of the corner of my eye that the transfer case lever was sliding out of gear under load, grinding, and when I pushed in the clutch releasing the load it would drop back into gear. The shift lever was adjusted properly and engaging fully, it was an internal problem.

This sounds very similar to my case. I have driven the truck about 200 miles the last 4 or 5 weeks and did not have any problems. BUT, the last time I used the truck before this I did put it into low range a couple times, so maybe it was not engaged fully.

 

[kylenobes]

Well I sure feel like an idiot now! I was so concerned about checking out the tranny & TC (and now I am finally working on it in the daylight) that I did not even notice I lost a torque rod.....

 

[R Racing]

Well at least it was a easy find !

 

[kylenobes]

Popped it back in temporarily (so I can move it around the yard) but I'll be replacing them this week.

 

[Trailboss]

Doghead called it!

You were lucky with the rod failure - see what could have happened when I had one pop out.
http://www.steelsoldiers.com/showthread.php?128863-Broke-down-again-Recoveries-Gone-Bad&highlight=