TH700-R4 automatic transmission. Clicking sound

[BoK5]

I have a 89' K5 Silverado Blazer 4-Wheel Drive with an automatic transmission TH700-R4.

I have started hearing a clicking sound when driving. It is not a loud clicking sound, it is only to be heard with the window down.
Having the transmission in 'Neutral' and raised the vehicle in the back. I can hear the clicking sound, when I rotate the rear drive-shaft forwards or backward. I first thought that the sound was coming from the transfer case. But lying under the car while rotating the drive-shaft, it seems that the clicking sound is coming from the transmission tail housing.
Observing the rear drive-shaft when rotating, I can hear the clicking sound exactly two times, when the rear drive-shaft is turned 360 degrees.
Transmission is correct filled.​

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I have checked the U-joints and they all OK.​

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I dont experience any problems with either transmission or transfer case. I have tried shifting from 2H to 4H to 4L and back to 2H everything works smoothly.

Anyone experienced same problem or having an idea to, what is causing the problem.​

Can it be the governor flywheel?​

 

[Greg Ducato]

Could be the governor weights for sure with the engine off in Neutral, or driving real slow in gear

 

[BoK5]

If it is the governor weights making the clicking sound, what will the risc driving?
Anybody have a link on how to change the governor flywheel on a TH700-R4 ?

 

[Greg Ducato]

No risk, it is normal for governor weights to make noise as the governor rotates slowly, if it is still doing it at more than 10mph then you have some other problem. The governor assembly is located behind the round steel cap at the drivers side rear of the trans. I'm sure there are some YouTube videos out there that can break this down.

 

[BoK5]

Thanks for the input.
I am still hearing the clicking sound when driving 25 mph. The clicking sound it not louder, just faster. The shifting in gears is working OK.
Any idea to what I need to pay attention to or be prepared for?