RMS73

The past few times I have 'gotten on' my '73 L82 the auto trans will not shift into third gear. Yesterday I looked at the tach and it was registering 5800 rpm and it was still in second gear, slowed down to about 3000 rpm and it shifted into third. Normally around town the shifting point is about 3000 rpm. So why won't the transmission shift at WOT or close to it?
Roger

gerry72

Probably the vacuum modulator on the trans. But this will cause other anomalies like a hard shifts too. If not the modulator (the easiest thing to check and replace) it's probably a sticking or broken governor.

jimvette999

I bet you're right on the governor....the plastic gear strips on those. I think if the modulator was bad, he would still get a 1-2 shift even if late.

TLChydraulics

Hopefully its one of the above listed problems, but if not, mine in my truck did same every time I stepped on it and it down-shifted from third to second, it wouldn't shift back up, it was my valve body spool sticking at the end of the bore and holding it in second. Although I tried to repair it a couple times, I ended up replacing the valve body.

Good luck,

Loren

Fubba

I'll tell you right now what I think it is. The same thing happened to me on my '71. It's the vacuum hose going to the modulator on the transmission. If it's the original hose, it's probably in really bad shape like mine was. It's most likely broken on the end allowing it to let some vacuum out which would cause it not to shift correctly. Check the hose. If not the hose, then it's the modulator itself.