High rpm shift

[Fiddlesticks01]

So recently you guys helped me solve a cooking issue now onto the next. This 86' bronco has a 302 in it edlebrock performer cam and crank, 4 barrel 650 cfm holly carb very nice tuned engine. One thing I don't like however is it loves to only shift around 3600-3700 rpm. In fact it will only shift in this range. I've messed with the kick down cable at the carb no change. So I put it back to how it was. Any reccomendations or am I stuck with a high shifting bronco

 

[miesk5]

Yo pal,

I just lost my reply due to screen refreshing.

I assume its a C6, if so,

Vacuum Modulator Troubleshooting; You have a modulator on the rear of the transmission. Pull the vacuum line off the modulator. If fluid comes out of the vacuum line,  modulator's diaphram is ruptured, replace modulator. If no fluid, check vacuum in the line with modulator removed, should be around 15 in.  If not, trace line back to intake manifold vacuum tree or vacuum block on firewall. 

C6 Parts Break-Out Diagram w/ Vacuum Modulator shown on middle, bottom of diagram.

See attached C6 Troubleshooting: 

 

[Fiddlesticks01]

Hey I appreciate the info I'll

Hopefully be able

To

Get it it this weekend. So a few most likely silly questions. Vacuum test should be done with the engine running I assume? And any reccomendations on what to use to measure vacuum just a basic vacuum gauge from auozone?

 

[miesk5]

Yo,

Yes, engine running. For safety, place the autozone gauge where you can see it from side of Bronco. May need some vacuum hose to place on the gauge and over the vacuum line to the C6. My dad once taped the gauge to a piece of wood so it would say in place on the ground to stop the engine vibrations so as to make gauge readable. It will probably be shaking.

May need 5\32" or 3/16" hose.

Also use Vacuum Gauge for general engine diagnosis, see

http://www.gregsengine.com/using-a-vacuum-gauge.html

I miss the old time mom & pop parts stores! They used to know sizes for everything!

GL!

Al