Coasting in 3rd gear hear clicking?!

[Don Crawford]

So if I let off the gas and I am in 3rd gear I hear what sounds like a loud clicking or almost like a slapping of a hose or something. I have been under the truck countless times and have looked for issues and have just about everything that was somewhat loose hemmed up now. I started putting in neutral during coast and noticed the sound goes away immediately. My question is what is it? And should I worry about, and how to fix it thanks guys!

 

[Greg Ducato]

What kind of vehicle? What kind of Transmission/transfer case/driveline???

 

[Don Crawford]

84 k5 blazer, 10 bolt front and rear with 4.88, has np 208c and a th400 tranny.

 

[Greg Ducato]

Cant think of anything in a 400 trans that would induce that on a coast down. The driveline is loaded during this event so my eyes would be on u-joints or driveshaft splines first. It is also possible that a snap ring in the transfer case could be broken allowing a shift in the internal components during coast down. The transfer case will sometimes pop into neutral when this happens. I would remove the driveshafts to check the joints, you wont be able to get an accurate idea of condition when the shafts are loaded in the vehicle.

 

[Don Crawford]

Roger that I'll have to take a look.

 

[diesel4me]

Look for zip ties on the drive shaft ?......

 

[Don Crawford]

No zips ties, but sounds stops immediately after I shift to neutral.

 

[diesel4me]

Long shot,maybe loose transfer case to transmission bolts,or loose torque converter bolts ?...

It could be some other component on the engine or rear diff telegraphing the noise ,making it sound like it comes from the transmission...I had a fan blade that touched the shroud only when letting off the gas on my van,and I could have sworn it was coming from the bellhousing.till one day I opened the hood and went to check the trans fluid--when I leaned on the shroud--"BRRING"..the same noise!..

 

[Don Crawford]

I hear you I have been looking everywhere but just can't seem to find it that's what makes me think it's internal, and the fact that once I go to neutral it goes away