Street Fighter TCI-411400 (C6) shifts too fast---Pleaese help!

[brad08stanggt]

I recently purchased and installed a TCI-411400 C6 Trans coupled with a TCI-441000 Torque converter. These are installed on a 67 Mustang with a 351c and 9inch rear.

I got the transmission installed, hooked up all linkages and vacuum lines.

The Vacuum modulator line is coming from manifold vacuum and meets the required specs of only 3 inches of rubber hose on each end and the rest is metal, there are no leaks.

The transmission will shift fine manually, with firm shifts from 1 to 2 and from 2 to 3. When in drive the transmission shifts through the gears much too fast. By 20pmh the car has already shifted to 3rd, even under heavy acceleration. Once in 3rd the trans won't downshift either.

What can I do to adjust this?

Thanks

I recently purchased and installed a TCI-411400 C6 Trans coupled with a TCI-441000 Torque converter. These are installed on a 67 Mustang with a 351c and 9inch rear.

I got the transmission installed, hooked up all linkages and vacuum lines.

The Vacuum modulator line is coming from manifold vacuum and meets the required specs of only 3 inches of rubber hose on each end and the rest is metal, there are no leaks.

The transmission will shift fine manually, with firm shifts from 1 to 2 and from 2 to 3. When in drive the transmission shifts through the gears much too fast. By 20pmh the car has already shifted to 3rd, even under heavy acceleration. Once in 3rd the trans won't downshift either.

What can I do to adjust this?

Thanks

Brad,
The modulator sounds like it needs to be adjusted. I would turn the screw on the modulator in 1/2 turns at a time. The shift separation should improve by turning it in. Please feel free to call, email or reply with any other questions.

Thanks

[brad08stanggt]

Russel, thank you.

Can you also please let me know what the recommended idle vac reading should be?

Thank you.

Russel, thank you.

Can you also please let me know what the recommended idle vac reading should be?

Thank you.

Should be at least 13-15in at idle.

thanks

Russ

[68hottrod]

Well on most Trannys there is a little adjustment screw inside the modulator valve where the hose goes on. You can stick a small screw driver down into the tube and turn the screw to adjust the shift points. I think (but its been awhile) that clockwise makes it quicker and counterclockwise spreads the shifts apart some but you may have to experiment to get it just right. Hope this helps some.

[brad08stanggt]

Well on most Trannys there is a little adjustment screw inside the modulator valve where the hose goes on. You can stick a small screw driver down into the tube and turn the screw to adjust the shift points. I think (but its been awhile) that clockwise makes it quicker and counterclockwise spreads the shifts apart some but you may have to experiment to get it just right. Hope this helps some.

Hi Russ and 68hottrod,

I confirmed using a vacuum gauge that I have ~13in pressure at idle. Turning the modulator valve in, clockwise, in 1/2 turn increments yielded little improvement. I then tried adjusting the valve at 2 turns per adjustment and I was seeing SMALL amounts of improvement. At around 20 total turns in I feel I got the "best" overall improvement, but it is still shifting WAY too soon, still barely touching 3000rpm. Manual shifting remains good. Around 26 full turns in I noticed that it got much worse at shifting so I left it in the 20 total turn interval.

I would still like this to shift properly in the D position and I do not want to do anything to harm the transmission. Please advise on anything else I can do to improve the shifting.

Thanks

Hi Russ and 68hottrod,

I confirmed using a vacuum gauge that I have ~13in pressure at idle. Turning the modulator valve in, clockwise, in 1/2 turn increments yielded little improvement. I then tried adjusting the valve at 2 turns per adjustment and I was seeing SMALL amounts of improvement. At around 20 total turns in I feel I got the "best" overall improvement, but it is still shifting WAY too soon, still barely touching 3000rpm. Manual shifting remains good. Around 26 full turns in I noticed that it got much worse at shifting so I left it in the 20 total turn interval.

I would still like this to shift properly in the D position and I do not want to do anything to harm the transmission. Please advise on anything else I can do to improve the shifting.

Thanks

Brad,
If you were adjusting the modulator that much and yield very little differences i would have to say your governor is stuck or the modulator valve is to short. Being that we built the trans i would say the modulator valve is right and the governor could be stuck. Ford transmission have very sensitive governor's when it comes to debris. Pull the tail housing and clean the governor and give it another try!

thanks

Russ.

[brad08stanggt]

Thanks Russ.

I'll have to find some time next weekend to do this.

If the car is shifting fine manually and the early shifting is the only issue is it safe to drive like this? Is this causing damage? It seems to operate well despite the early shifting in Drive. I haven't driven it much though, only a few miles testing when I was adjusting the modulator.

Thanks Russ.

I'll have to find some time next weekend to do this.

If the car is shifting fine manually and the early shifting is the only issue is it safe to drive like this? Is this causing damage? It seems to operate well despite the early shifting in Drive. I haven't driven it much though, only a few miles testing when I was adjusting the modulator.

Brad,
It should not hurt the trans but you need to make sure it is adjusted right. Also one thing make sure you have the kickdown cable hooked up and adjusted properly as well.

[brad08stanggt]

Hi Russ,

I finally got around to cleaning out the governor. I noticed an improvement, but its still not 100% how it should be. Some times it will start in 2nd gear. I also had another issue come up yesterday. After about a 30 minute drive the 1-2 gear shifts saw about a 5 second delay followed by a hard shift into 2nd. This happened about 5 times. 2 to 3 shifted perfectly as usual. I checked all connections and fluid levels. After the car sat for a bit shifting returned to normal for the ride home.

What could have caused this? It would just hang in first, i would hold the revs steady, then it would shift hard.

Thanks,