Someone Play Taps for my Getrag (I think)

[driverswanted]

There's a whole lotta shakin' going on. I think my Getrag puked again after one year on a rebuild. Even filled up higher with a street Ell added to fill port. Kinda weird. I can drive it at times now with it not shaking, then sometimes it just starts shaking. Sorta feels like a disc brake hanging on a rusty rotor. Only clue that it's the transmission at this point is the outside of the transmission was about 110 degree (normal?) to the touch after a 35 mile no load run. Not a drive shaft either; checked both sections.

Someone tell me; I had been experiencing a chirping horn type sound, just a short burst sound when I let out the clutch. No slipping, just the chirp when I let the clutch out in a hurry.

Is that the pilot bearing or a pressure plate issue?

 

[Philip]

Have you checked the pinion bearings for being loose/bad. This will cause a vibration that can be felt threw the trans shifter. It will also cause the pinion nut to backoff and if it is a $X$ truck it can loosen the nut holding the yoke on the transfer case output shaft. With our trucks being noisey. By the time you hear a rear axle howling it has all ready got expensive.



Most of the time if you have bearings going bad. The temps will raise on the affected part. If the trans is normal temp. That is why I sent you towards the rear axle. Vibrations will travel in the drive train.



On that chirp I would need to hear it.

 

[driverswanted]

I have to admit I had not gone to the pinion yet. Just wiggled the front and center support bearing areas at this point. Do you know wha ta normal temperature is for the manual Getrag ubder no load?

 

[Scot]

The chirp is the throwout bearing. Also check the center driveshaft carrier bearing for the vibration.

 

[Philip]

Do you know wha ta normal temperature is for the manual Getrag ubder no load?

Not sure. I have never ran a temp gage on anything light duty like our trucks are. But I have driven semi's with temp sensors on the trans. With a GVW of 80k doing something close to the speed limit ( )on flat ground. The road ranger would show 200 degrees.



I wouldn't want to see above 150 degrees myself on the getrag.

 

[driverswanted]

Scot,

When I changes put the rebuilt Getrag back in I changed the throughout bear ing and just prior to that I changed the center support bearing. I originaly thought the chirp was the throughout but when it did not go away I became suspicious of the pilot and clutch areas. Is it possible for the slave hydraulic cylinder to make a noise like this if hydraulic fluid were to squirt past an o-ring or something in the cylinder? I occasionaly get the feeling that the pedal back pressure mometarily drops off just as it chirps.



Philip,

I can keep my hand on the transmission so i guess that means I'm below maybe 135-140 F.

Any one know how to test for the pinion problem?

I do believe the vibration is shaking the whole truck and very little through the shifter if any. . Can't determine if it's up front or in back.

 

[Philip]

On the pinion you need to jack the rear tires off the ground. Turn the pinion by hand. If you feel any roughness or catching or side to side play then you have problems.



If you find any of the mentioned items. It is time to pull the axles out and check again. By removing the axles you are removing the hub bearings out of the test. If you still feel something with the axles removed. Then it is most likely a problem with the pinion or bearings.



If you remove the axles and the pinon turns freely. Then turn the rear drums and see if one of the bearings in a hub is bad.



You didn't state how many miles are on your truck. But in all my years of working as a mechanic. On the model 70 rear axles. I would see bearings starting to go around 150k. If they had not had the recommended service done at the proper mileage interval's.

 

["Mad Max"]

D70

My D70 was toast when I got it at 207k miles. Needed complete rebuild. Pinion and ring gear completely shot to hell along with all bearings and posi. When driving whole bed sounded like it was singing, didn't really narrow it to the rear end until we opened up the rear slider window and the volume tripled. Got quiet when off the throttle, but just sang along when on the gas. Got it all repaired and now nice and quiet.



BTW, I'm looking for a dually D70, 3:54 posi w/ limited slip. Any help? Doing a dually conversion, can use current 70 single rear as trade, etc etc.



- Sam

 

[driverswanted]

Maybe I should drain a little of the oil out of the rear end and check it for metal. Does the pinion get/share lubrication with everything else in there?

I hav'nt done any of these tests yet because my #*%$# Blazer (last working vehicle) also decided to blow a transmission coolant line. Oh and did I mention the serpintine belt started to shred at the same time? Starter is going to go too. That makes three items gone... . hmmm. Does trouble come in threes or was it fours? Something better start working right or I don't go Salmon fishing next month.

 

[AMikonis]

Philip, what other procedures can you recommend to us shadetree types for checking out the rear end? In my case, I don't think it's noisy, but the oil is pretty murky, I know it's been run low because of bad axle seals, and it has more than 150K on it. With all these differential stories lately I'm getting concerned...



I realize you can't tell everything without a teardown, but what can we check/ look for when we pull the cover off? Just hate to take it to a shop blind...



Thanks,

Andy

 

[Philip]

Hi Andy



Another check is pull the axles. Get the correct socket for the pinion nut. For orginal bearings the "Breakaway torque" is 10-20 in. lbs. For replacement bearings it is 20-40 in. lbs. This is the amount of torque it should take to turn the pinion. It should be done with the the carrier out. But if you come up with a reading above the minium with the carrier in then most likely you are all right.



I just did a full load of bearings on Case500D's 92 3/4 ton rear axle a while back. His axle had been howling.



In a couple of weeks I have to do a ring and pinion job on his 93 W350 on the real axle.

 

[driverswanted]

Nuts!

Guess what... . The problem was only the nut on the tail end of the transmission output shaft. It had spun off because the @!*&%! transmission repair man had not torqued it down properly. I put it back on with some permanent type locktite added. The only other problem was that the front drive shaft had slid backwards and pressed the water slinger ring up against the rear end of the front tube causing aome friction and somewhat elevated tempertures on the shaft forward of the center support bearing. Found this with a hand held infrared temperature meter while scanning the entire drivetrain for the vibration problem. That was the clue that something had pushed the front shaft backwards. The nut was held captive but loose forward of the first universal joint, binding and causing the driveshaft to jump. NO damage to the transmission output bearing.

Now I can tow the boat to Ontario for my annual salmon fishing trip. Tite lines and smooth drivetrains everyone.