Trans locking and unlocking during cruising

[79TurboTA]

While cruising around town or on the highway, the engine RPMs will drop down to near idle levels when I take my foot off the gas. It does this no matter what speed I'm traveling or what RPM the engine is turning. The fluid is full and the trans shifts very solidly otherwise. Just curious why it's doing this. The converter is a PTS 3200. I have other cars with loose converters and they don't do this. Any ideas? Thanks!
Brad

 

[SSedan64]

Does this happen in Manual 1st, 2nd, 3rd etc.. May be a problem with the overrun clutch. Post more Info.

 

[79TurboTA]

It does it in pretty much every gear. I'm not sure how to explain it any better than I did. LOL Letting off of the gas is like pushing in on the clutch in a manual trans car. Once I take my foot off the gas, the RPMs drop to idle and as soon as I hit the gas, they raise back to where they were previously. Hope this helps.

 

[SSedan64]

No Engine Braking

My best guess is the Overrun clutch piston seals or clutches are burned since it does at in every gear. Looking thru a ATSG manual the other things listed when 1st, 2nd, & 3rd forward gears have no engine braking is>
valve body gaskets bad/leaking
manual linkage misadjusted
D-3 oil hole plugged in turbine shaft
overrun clutch backing plate snap ring out of groove
PT/D-3 checkball mispositioned
D-3 orifice in spacer plate plugged

 

[79TurboTA]

Thanks for the detailed info bud. Apparently I have some R&R on the tranny in my future. Is there any harm in drving the car? Like I said, it shifts firm, but I don't want to ruin it completely if I drive it. I have a trans guy here local that can rebuild these so I may have him look it over. Thanks again.

 

[SSedan64]

I'm not sure if it will cause further damage or not, but I'd check with a builder or maybe someone on here can tell you for sure.
I'd make sure before you drive it tho'. It has or will be adding clutch material & then metal to the fluid if it's the overrun clutches.

 

[79TurboTA]

Crap. Good point! Good thing it's winter here. I'm not tempted whatsoever to drive it. LOL Thanks again.