Since I've had this 2002 van for a year and a half I have felt and heard a clunk when it feels like a loss of power and then the clunk as it catches into gear (?) for a split second. I have had the transmission replaced with a rebuilt (it was starting to slip), but still have the same issue which is very intermittent. Sometimes happens a few times within a minute or so, and often doesn't happen on some trips. Seems more often during a climb and has happened anywhere from 30 to 60 MPH.
Any ideas would be greatly appreciated. It's a 3500 with about 130k miles, the 5.2 liter V8. It was a government van, probably bought at auction before I purchased it.

 

if engine pops out intake it could sound like a knock with a loss of power than recover ..but tHats just a gess

 

Thanks for replying Wheily.
I don't know what you mean by engine popping out intake, but I can feel the whole van shudder when it happens, but very fast.

 

TCC shudder maybe?

 

Thanks for the reply HeyYou. The clunk makes the van feel as though it goes in and out of gear very fast and lasts just a split second, even after the rebuild was done. I'm wondering if it might be something electrical or whether it might be coming from some differential problem.

 

When the trans was rebuilt, did they replace the electronic in the trans? Toque converter?

 

It was swapped out for another rebuild in November 2024. I don't know if any electrical part was changed other than what might be needed when replacing the transmission. Isn't there a solenoid switch involved with the timing of the gears shifting? Often when the hard clunk happens the van's already in 4th gear, so not really shifting into a higher gear, doing about 55-60 mph. Do you think it might be some electrical control that was not changed? Thanks for your help.

 

If they changed the entire trans, then likely they changed all the electronics as well. Torque converter is still open to question though.

46RE trans more'n likely.... So, 1-2, 2-3 are actual gear shifts, electronically controlled, of course. Once in third gear, should get a slight RPM drop when TCC locks, then, when above 42mph, it'll shift into O/D, which should be a pretty significant RPM drop. after that, there is nothing else to happen.....

 

Thanks HeyYou! Every little bit helps.

 

are you sure it isnt like a total engine shutdown for a split second? or the alternator grounding out? something werid like that?
Ill ask the other guys help here - but wouldnt a CPS/Distrub pickup that abends for a second make it feel like the trans slipped?