Noise?

[Mark's RMK]

Just got back to Mn from Wyoming, 2670 miles pulling a 24' box, 5' v-nose aluminum trailer with 4 sleds with 2004 Chev Suburban 1500.

On the way out I-80 going down the first big hill into Laramie we heard this odd random clumking noise. Looked all around, didn't see anything. Drove on to Saratoga,back and forth to the Snowies and the Encampment lot, no noise.

Driving on to Pinedale the mysterious noise would come back north of Rock Springs. Just often enough to make you wonder if you would make it.

Drove back and forth from Pinedale to the Sherman lot, no noises. Lighter load with all luggage removed.

Left Pinedale and going down South Pass into Lander we wondered if we again were going to be okay. Got on the flats, noise gone.

Couple of times it clunked going from Lander to Casper. Then every so often it would make the noise. Not enough to warrant pulling inot the Chev dealer for a looks see.

We could not replicate it with bumps, moving steering wheel, putting on brakes.

It seemd like if you slowed down and then started up to speed it would reoccur.

Today we drove from Mitchell SD to Mpls and it didn't do it until we hit traffic and lights in Mpls.

I put air bags in to help with the tongue weight and luggage. I have 20 psi in them out of a maximum of 40.

Could it be the gabs moving against the coils? It almost sounds like some pent up spring loaded energy. Temperatures were mostly 32 and lower.

The other weird thing, out of the 4 of us in the vehicle, no one could tell where they thought the noise was. I would have guessed driver front, those in back thought it was behind them.

Any ideas? I sure don't think it would make any sense to the garage.
4 wheel drive seems to be working okay. Could there be any gremlins popping the solenoids in and out? Felt nothing in the steering or controls. Also did not seem to happen over 65 mph. Downhill we were up to 75 at times with no sense of vibration or anything.

Receiver hitch is tight and only a slight sensation approaching a stop light and leaving as any minor slp was taken up from braking and then pulling.

Thanks for any suggestions anyone has.

 

[←snow∞motion→]

Try greasing your slip joint on your drive shaft. There is special grease that goes inside the splines allowing free movement. When it's dry or old it can slam back and forth, especially when stopping or slowing down.

 

[Mark's RMK]

Splines?

Do you mean the front one?

The rear is lubed by the automatic transmission, right?

 

[tree climber]

grease the ball? this only happens when your towing your trailer right?

 

[←snow∞motion→]

Do you mean the front one?

The rear is lubed by the automatic transmission, right?

The front "slide" joint that goes into the transfer case. When pulled out of the transfer case, there are splines inside the slip joint, they need Teflon grease.

If they are dry it doesn't allow the drive shaft to slide freely back and forth under different levels of torque, or braking and acceleration.

Some people use simple wheel bearing grease or Slick 50 synthetic, but the dealers use "special" grease. Ford has a blue synthetic "smurf" grease, and GM uses a peanut butter looking grease.

I don't have any specific part number for the GM grease, but the Ford part number is D2AZ-19590-A.

From the conditions you speak of when this occurs this should fix your problem in my opinion, but obviously without seeing it myself I can't guarantee results. But it's an easy fix and worth a try. All it takes is disconnecting the rear drive shaft from the rear axle and sliding it out of the transfer case, and lubing the inner splines.

 

[Goinboardin]

x2 on the slip joint grease. My truck did this for a while, used the GM grease (my dad said it works better than the ford stuff, and he's a ford tech) and it solved the problem. For a while anyway. Bought a new yoke for about $70, installed it with more GM grease, and now the problem is truly gone (now that I say this it's probably going to start again tomorrow). Has been for 4 years.

 

[Mark's RMK]

Clunk

Talked to my local Chevy dealer here in town. He said the grease only lasts 2-3 months and he kind of poo pooed it.

Said the special oil in the transfer case for the automatic AWD seems to dissolve the grease?

I asked about the new Suburban's and he said the 6 speeds have a different design to get rid of the clunk. Not sure what that means unless the transfer case uses a different lubricant.

Thaks for your replies.