Question: Hard engagement from Park to drive?

[captcorvette]

Most likely something I am overlooking but so far the penny has not dropped! Moving the shift lever from Park to Drive it is a hard abrupt engagement. I THINK I have checked all the obvious. RPM too high (nope), drive shaft U joints worn/sloppy, nope. Transmission fluid level incorrect. Checked and OK. Dirty fluid? Nope. Car only has about 18,000 original miles on it and been a garage queen until I bought it. No smell of burned transmission fluid. All drive line connections seem to be good.

OK folks what am I missing here.

 

[toobroketoretire]

If it's fast idling at 1500 rpm when you drop it into DRIVE it will be harsh. But when warmed up and idling at 750 rpm it'll be pretty gentle.

 

[captcorvette]

No this happens when the idle is below 1,000 or even at the warmed up engine idle of 750 rpm

 

[toobroketoretire]

No this happens when the idle is below 1,000 or even at the warmed up engine idle of 750 rpm

Then it could be a bad modulator valve or a bad leak in the hose that goes to it. Do you have a TH350 or TH400 transmission?

 

[captcorvette]

Its the stock Th350. Will double check the line but thought I checked it properly. Won't hurt to check again. I would be surprised if it was a part worn out what with the low mileage. High years---yes. But has been a hanger queen.

 

[toobroketoretire]

The short hose down at the modulator gets oil soaked over time and swells until it comes off; making a pretty hard "clunk" going into gear and hard downshifts. You should be able to apply vacuum to the top of the line where it connects to the intake manifold and it should hold vacuum.

 

[captcorvette]

Thanks. Will give this a try tomorrow as soon as it get to the shop. I am 9 hours ahead of your time zone. But will post up tomorrow when I have had the chance to check. Your 82 a CE?

 

[captcorvette]

Checked the lines again. All good and holding vacuum. So it looks like I need to change the unit. Thanks again.