Banging on deceleration

[Mr. Alligator]

I have tried search function, but can not seem to figure this out....

1997 SOHC with automatic transmission. All wheel drive four wheel drive. If back tires slip, front tires automatically engage. Selector switch allows four wheel drive high and four wheel drive low.

Transmission engages well and shifts well up and down through the gears. However, when the engine is used to slow the vehicle (like turning O/D off coasting down mountain roads at about 50 mph), I get an intermittent popping noise and can feel banging through the driveline. This is more dramatic as the engine is used more to slow the truck. It seems to be mostly in the front of the truck, but I can not be positive,..

If I shift to neutral, the problem does not appear.

If I am accelerating or traveling up the mountain, the problem does not appear.

I do not notice this in town during normal driving.

I do not notice problems cornering.

All four tires are the same size and at the same tread life.

This is a high mileage vehicle: The front differential, the rear differential, and the CV joints are original.

I recently paid a shop for a rebuilt transmission, which they diagnosed as the problem. But this has not improved or changed the situation.

Thank you in advance for your help and wisdom!!!

 

[Mbrooks420]

Pull your driveshaft and see if it does it.

 

[domct203]

Pull your driveshaft and see if it does it.

Agreed. Pull the front driveshaft. If the problem goes away the problem lies in the front driveline, or possibly the transfer case.

Did you replace differential and transfer case fluids?

 

[boominXplorer]

Another vote for pulling the driveshaft here. Try taking off hard from a stop before you pull it, if it pops/clicks its time fore a new one.

 

[Mr. Alligator]

Pull your driveshaft and see if it does it.

Thanks. I will try this. The condition has recently gotten worse, and the front end clunks when I put it drive or reverse.

Agreed. Pull the front driveshaft. If the problem goes away the problem lies in the front driveline, or possibly the transfer case.

Did you replace differential and transfer case fluids?

Thanks. Yes, the differential and transfer case fluids are fresh.

Another vote for pulling the driveshaft here. Try taking off hard from a stop before you pull it, if it pops/clicks its time fore a new one.

Thanks. It seems much more related to deceleration than acceleration. Could the front drive shaft be the problem? I will check front u joints.

I appreciate the help and wisdom. Thanks!

 

[Mr. Alligator]

Follow up/ issue resolved: this was the transfer case problem. Rebuilt transfer case fixed the problem.

Thank you on the Forum for your help and kindness.