modulator valve bad?

[SuperCab]

I know that sounds contradictory; let me try to explain...

After cresting the hill, the engine revs as if it's in neutral and seems to coast, but if you really push the gas, it goes in 2nd gear.

There is ample vacuum at the modulator.
I havn't checked the vacuum with a guage, I should do that today.
Havn't really checked the timing, I'll check that too...

[VileZambonie]

The modulator diapragm acts upon the modulator valve. The actual modulator valve is in the valve body. I'll try to simplify:

Governor pressure is proportional to road speed. The more governor pressure rises it will force an upshift.

If modulator pressure which is proportional to engine load  over comes governor pressure it will force a downshift or delay an upshift.

The detent cable is directly proportional to driver demand. When throttle pressure is high it will force a downshift.

And for beavis and butthead "the angle of the dangle is directly proportional to the heat of the meat"

Make sure all of those basics are set correctly first and then we can move on. Adjusting the detent cable is done at the carburetor. Depress the tab and push the plunger toward the firewall. Now actuate the gas pedal to the floor. This will give you a base setting.

[Russ130]

Vile I think you are talking about a tv cable adj., the detent or kickdown cable should be about halfway in the slot at idle. Now correct me if I'm wrong but isn't the only way a th350 is going to downshift going downhill is if there is a crack or porosity somewhere in the tranny?

Myself, I'd get my money back or at least get a couple hundred knocked off to cover a used tranny if the engine checks out ok.

He could just disconnect the kickdown cable and avoid any kickdowns caused by the cable at least just to see if it still happens or not.

Vile - I don't mean to step on your toes with the cable thingy but it just sounded like you forgot that it was a kickdown cable and not a tv cable.

Supercab - That may not be the right way to adj. the kickdown cable its just where mine is and it works perfectly for my truck.

[VileZambonie]

Why would you think that? When driver demand (detent cable) is high it forces a downshift or delays an upshift. TV cable does essentially the same but varies throttle pressure regulating line pressure in 2004r, 700R4. The base line adjustment is the same.

No, a cracked case or porosity is not what can only cause his problem. As a matter of fact that's a rare issue unless there's been physical abuse to the driveline. That's usually an issue with a new or reman unit not functioning correctly.

[Russ130]

So you set a detent (kickdown) cable the same way as a tv cable?

[VileZambonie]

Some detent cables have the same design as what you would see with modern TV cables. Others have a spring and retainer clip that you can pop up, adjust and lock back into place. I'm going to look at that blazer right now but if you google detent cable I'm sure you'll see plenty of pix.

[SuperCab]

Wow! Finaly found the problem!

The governor was worn out.

The spec on the governor lands is .800 inch. Mine mics at .793.

Replaced the governor, works great now.

[VileZambonie]

glad to hear.