c-6 trans

Charlton · #1 (**permalink**) 09-05-2001, 06:08 PM

Can anyone out there help me? I have a C-6 trans. When I step on the gas in drive, the engine accelerates to 6500 rpm without shifting. If I let off the gas, it shifts fine.
Fortuately I have the rev limiter set at 6500 so it starts to crap out instead of blowing up.
My question is, is there a way to adjust the trans so it will shift at 6000?

wadesdad · #2 (**permalink**) 09-05-2001, 06:39 PM

I am definately not well informed, but I'll give it a shot. I'm sure someone will chime in afterward. I can think of two things.
1. Kick down linkage not hooked up properly.
2. Vacuum not pulling on valve body properly.

These should be relatively easy fixes.

jdean · #3 (**permalink**) 09-05-2001, 07:57 PM

You may already know this, but....you might also look at the vacuum adjustment. If you detach the vacuum hose at the transmission, there is a screw inside the vacuum modulator that can be turned in or out to adjust amount of vacuum received from the engine. This will impact the shift points so that they are early or late.

I'm curious.... what is your rear end ratio?

Charlton · #4 (**permalink**) 09-05-2001, 10:53 PM

Rear end is a 350. I think the kickdown is correct, and I didn't know about the vacuum adjustment. Thanks for the response, I'll check them out and be back.

Frank Coppola · #5 (**permalink**) 09-06-2001, 12:52 AM

I have a C-6 that has the opposite action. It shifts at 1,000 rpm. I assumed that was normal due to the power of the engine, plus I have a ratchet shifter for "fun" driving. The shift point never really bothered me.

However, can I adjust the shift point higher at the vaccuum modulator?

CobraEd · #6 (**permalink**) 09-06-2001, 05:12 AM

The vacume modulator is the key. Not sure they are all adjustable. During the 70s for emissions reasons, some of the vacume diaphrams had two ports, one to offset the normal vacume pull undercertain conditions.

I had a 73 Gran Torino with a 351 Cleveland and a C6 that had this double vacume hose on the diaphram. The car would shift VERY early untill I pulled the "extra" vacume hose.

Ed

jdean · #7 (**permalink**) 09-06-2001, 11:15 AM

You should be able to adjust it and make a difference. I THINK you screw it clockwise to restrict vacuum and make it shift higher. I would experiment with it. Pretty easy and quick process.