C6 - no third gear

[mad2smile]

while driving in the "D" position, my truck only has first gear. if i manually shift to "2", second is fully usable. if i shift back to "D" and rev up pretty high, it feels like its trying to grab third, but for some reason it cant.

when i installed my B&M Shift Improver kit, i did not tighten up the main band because the locking nut on the adjuster screw was really tight. the transmission worked just fine before installing the kit. could the band be too loose? the shift kit said to tighten it up, but like i said, i didnt b/c i didnt want to break the adjuster screw while trying to loosen the locking nut.

[Joshpow]

The band might be your problem, but if it only showed up after a shift kit, I'd lean toward a problem in the valve body. I am having a similar problem with a c4. If you let up on mine, it will eventually fall into 3rd. Then, it pulls. I have no idea what is going on, but I will let you know what the answers to my post are, being the problem is similar. Only mentions I've had so far are vacuum modulator, which isn't my prob, bands, which didn't cure it, and someone else said I could have valve body or servo problems. Hopefully someone will come up with more positive info for you though.

[mad2smile]

okay. hope it isnt valve body (dont really want to pull the pan back off). i'll try tightening the band and verifying the vacuum connection.

[Joshpow]

The servo requires the valve body to come out too as far as I know. Let me know what you find.

[fordman]

did you check your fluid when the trans was warm?

[71HANKER]

with the shift kit, did you actually go into the spool valves inside the valve body, or just the new gasket and modifying the separator plate? I had the exact same problem too when i rebuilt my c6 last month. I had to pull the valve body again, but i found out that the brand new separator plate gasket had blown out, and one of the spool valves inside the valve body was stuck. My buddy who's worked at a transmission shop for 25+ years told me that on ford c4's and c6's, that valve body gasket blows out quite often and that you don't even need to run it. Just the metal plate. I checked those two things and now my truck can bark 2nd gear, and i have 38's. Check it out.

[Joshpow]

71HANKER,
What other problems might that cause. Also, what could cause a c4 to try to engage 2nd and 3rd at one time?

[71HANKER]

are you asking about removing the valve body gasket? The only problem you'd have is if the valve body is warped, then it wont seal anyways. as for your c4 trying to shift into 2nd and 3rd at the same time, i think it might be a problem with either the spool valves in the valve body or maybe even the check balls. I havent run into that problem before so im not sure if im any help with that.

[papabug71]

71HANKER,
What other problems might that cause. Also, what could cause a c4 to try to engage 2nd and 3rd at one time?

Josh, I am by no means a Ford auto tranny expert. But, my Chrysler 727TF was doing that. Its called "band overlapping" or something along that line & it means bye-bye tranny if you nail it hard while its in that condition..

Another reason: Automatic trannys pi$$ me off.

Better take it easy on it till you get a for sure answer.

[fordman]

the 727 is a better trans than the 904.

[Joshpow]

It is at home still until I get it figured out. I only drove it a short distance when that happened. Kept it out of third on the way home and no problem with that. I expect a full rebuild before its over. I got some bad looking fluid too. I may just try to find a hopped up replacement for it. Just a shift kit, cooling galley rework, and extra clutches. Not sure what money will allow though.

[mad2smile]

i tightened up the main band, but there was still no difference. then i started checking for vacuum. there was little or no vacuum reaching the transmission. changed my vacuum routing a little bit, and she runs perfect now.

[71HANKER]

Awesome man! im glad you figured it out. Always check the simple stuff first and sometimes you get lucky. I had to replace my old metal tube to the vacuum modulator too, it had so many kinks and bends in it that it wasn't pulling enough vacuum. good job.

[Joshpow]

I'm glad it worked out mad2smile. Don't you love the trouble piddly stuff causes!? Hopefully I'll get mine figured soon. I sure miss driving it. Called TCI and I believe their transmissions are the way to go. I am not sure the tailshaft will work though. Mine has a short housing with bolt on yoke. Theirs seems to have a slip yoke. Does this sound right to you guys? Can it be swapped without going inside the transmission? Thanks for the input so far and sorry for the post hijack.

[mad2smile]

mine has a slipyoke. ive never seen one that didnt, but then again, ive never seen the underside of a '60s F-series. id go for it, and just rework your driveshaft...