Just replaced a failing torque converter with a rebuilt from a very reliable transmission shop's rebuilder. Had drained the transmission so I added four quarts of ATF and started it in neutral. Only ran it for several seconds as it made a terrible knocking noise. By putting a socket & breaker bar on the crank front pulley, I could make it make the same sound by rocking the crank back & forth.

This suggests to me it's a converter internal problem? On reliable advice, I didn't put ATF in the converter before putting in on transmission as I was told that the pump would gradually fill it all up as I slowly added ATF while checking the level. Could it be that the pump is not priming the converter as it should to accomplish the filling process?

Converter fully engaged trans input shaft spline and pump notches and pulled up snug against flex plate when converter bolts were installed.

Any ideas out there? TD

 

I added a quart of fluid to the torque converter before I installed mine. Didn't have any knocking sounds.

 

So I guess the question remains, if the the remanufacturer didn't put in any fluid, and I didn't put in any before installation; while the pump is filling the converter, how much clunking might there be, for how long and is that normal, or indicative of a problem?


Horse sense told me to add a quart first but I let my human brain rule my actions!!

 

The guys that did my trans told me to add the fluid before.


Those things hold a lot of fluid. I don't know the pumps pressure/ how long it takes to fill everything.

 

Well, all's well that ends well, so I will add a happy ending to this mystery so that anyone who might encounter this anomaly may benefit.

A technician from my local transmission shop made a house call and like me was mystified as to why this clunking was heard at the converter. After several minutes he noticed the smallest movement of the flex plate independent of the converter which seemed impossible as the bolts were very tight with red thread locker on them.

Bottom line is that the Volvo bolts were slightly longer than the hole depth on the aftermarket converter. They were very tight to the bottom of the hole but only snug against the flex plate at the bolt shoulder. I ground the bolts down about a .100 " and the noise went away and everything is good. Go figure!!!