Tootie Pang

iTrader: (2)

Freeway in 4th gear all is well. Punch it to the floor and it downshifts into I don't know but the RPMs go sailing off.

It down shifts fine from about 45-50 mph (drops into 2nd I think).

I think it's trying to downshift into second at 65 mph as well but have been timid about seeing what will happen.

The car originally came with 2.73s and I installed 3.42s. The speedo gears have been set correctly and the TV cable is set correctly.

I have not touched the governor.

If I 3/4 throttle it on the freeway, it drops to third gear no problem.

Trans runs fine and has been serviced. Corvette servo mod done but had no effect on this downshifting problem.

RBob

iTrader: (1)

Need to mod the TV plunger sleeve. Check the 4-3 WOT thread in the sticky's.

RBob.

Tootie Pang

iTrader: (2)

I'm not sure the WOT 3-4 shift sticky is my solution. That's for WOT upshifts. Mines downshifting into RPM la la land.

RBob

iTrader: (1)

If it up shifts 3-4 at WOT, how could it downshift under the same conditions?

RBob.

Tootie Pang

iTrader: (2)

I think the difference is 3-4 WOT upshift occurs at 115-ish land. I'm looking for a problem with my 75 mph 4-3 downshift.

RBob

iTrader: (1)

Whatever...

RBob.

OrangeBird

iTrader: (1)

OOps , my bad , my post here was based on my misunderstanding that I thought the OP was only slightly pushing on the gas , when I reread the first post I see that the OP is punching the gas to the floor , which is a different situation than I based my answer on .

Sorry for the edit , and good luck with it

Fast355

iTrader: (2)

At 75 mph downshifting to 3rd would not put you in RPM la la land. Sounds like it is downshifting into 2nd gear. Could very well be a governor calibration issue with the gearing change. Try a governor from a TBI Van or Truck and see what happens. It will only shift about 4,500 rpm at WOT, BUT it is more correct for the 3.42 rear gear.

Tootie Pang

iTrader: (2)

Thanks! I will look into that. These stock 305s really run out breath. 4500 RPM doesn't sound unreasonable to shift at with closer ratios.

sofakingdom

iTrader: (1)

Sounds like your tech reads high, like everybody else's.

That's how that particular trim package in these cars fails.

Tootie Pang

iTrader: (2)

??

jmd

iTrader: (4)

3-4 WOT mod first.
VB and gov. from. G92 third gen V8 ideally.
Or, re-cal the gov. yourself (more time consuming.)

sofakingdom

iTrader: (1)

The factory "tach" (I use the word loosely) circuit is about the crappiest possible thing that would make a pointer wave, and thereby impress new-car buyers 35 years ago, that had never before seen such a thing, that their new car is "sporty". You're obviously kinda young.

They fail in these cars by reading high. REAL HIGH. I have (had?) one in my collection that read 3 times the actual RPM.

Moral of the story being, if your tach reads "red line" during normal driving, it's probably fornicated in the usual way. Which in turn means, your ACTUAL engine RPM might be some completely normal figure, but your "tach" goes into spazz mode.

Eeeeeeezy enough to verify by checking it against an actual piece of test equipment. You'll likely find that it's reading some percentage high, like say, 50%; actual = 500, dash says 750; actual = 2000, dash says 3000; actual = 4000, dash says 6000; and so on.

Tootie Pang

iTrader: (2)

I had my tach repaired and calibrated...

Tootie Pang

iTrader: (2)

Ok, sounds like the way to go...

sofakingdom

iTrader: (1)

So, maybe it was accurate for a day or 2; or maybe not. They don't just "break" and start reading weird; rather, a part that controls their accuracy, degrades continuously.

Check it anyway, you might be surprised.

Tootie Pang

iTrader: (2)

Thanks. My scanner's RPM reporting matches the tach- for now...