tranny issues....
ok, after letting my bronco (78' bronco, 408,c6,205,etc etc.) sit for a while when i was changeing the power steering pump, i finally took it out driving again today, but for some reason i couldn't get it to go into 3rd gear, im under the impression that it has a manual valve body, (b/c you can put it in "D" and it will stay in first gear since ive owned it.) so shift it on the column 1st, 2nd, and shift to "D" for 3rd, today it wouldn't go no matter what i tried, it has always acted up a little, but usually when i would put in to 3rd and it wouldn't want to shift i would just down shift back to 2nd then back to "D" or 3rd and it would shift, today it wouldn't go into 3rd at all.
im not up to par on tranny's at all, so bare with me, is the c6 in my bronco run/shift off vacuum? i noticed also today that the engine was idleing at a little higher rpm's, it wasn't loping as hard....so i was thinking maybe vacuum leak?
or what? comments? advice? bacon?
Nick
is the "mushyness" in the column or the transmission somehow....
When in drive, does the trans shift at all by itself?
This trans is originally vacuum operated, but would no longer be if it truly has a manual valve body.
There is a possibility that you do not have a manual valve body, and have simply been driving it around with a bad vacuum leak, or bad vacuum modulator the whole time, and now since it has been sitting, the leak has become worse, and it is acting up on you. Could explain the soft shifts. How is the level? C6 screens can often clog and have an effect on pressure. Does it pull well, or does it feel like it slips?
When in drive, does the trans shift at all by itself?
This trans is originally vacuum operated, but would no longer be if it truly has a manual valve body.
There is a possibility that you do not have a manual valve body, and have simply been driving it around with a bad vacuum leak, or bad vacuum modulator the whole time, and now since it has been sitting, the leak has become worse, and it is acting up on you. Could explain the soft shifts. How is the level? C6 screens can often clog and have an effect on pressure. Does it pull well, or does it feel like it slips?
fluid level is good and clean fluid. drive it kinda feels different but 1st and 2nd are solid as a rock and when i shift to 2nd from 1st it kicks like a mule...where does the vacuum line go into the tranny?
a vacuum leak would make it idle higher right? b/c of it running lean....?
What happens when you put the shifter all the way down to low, or 1st? Is that no longer 1st gear?
Sounds like you have some trash or contamination in the valve body preventing the high gear. C6's only have a screen and not a filter, so the screen only catches larger particles and not the smaller stuff. Real common for then to stick vavlves and other valve body related components, especially after thay have been sitting.
If I start in 1 then shift to 2 then shift to “D” it wont shift, it will stay in 2nd gear. Usually b4 it sat for a while when I shifted to “D” and it wouldn’t shift, I would just go back to 2 then back to “D” then it would shift into 3rd most of the time.
Im thinking that I don’t have a manual valve body judging by what I just said, im thinking vacuum leak, at least that’s what im hoping
Where does the vacuum line go into the tranny at? To fix this just replace the entire line? Is it just reg. say rubber gas line or something or is it made of something special, sorry for the last few dumb questions, I havnt looked for the vacuum line yet….
If its not the vacuum line and is the trash in the valve body as you suggested, is that something that can be easily fixed in truck without digging into my c6 to much?
Thanks,
Nick
If you have a manual valve body 1st will be 1st 2nd will be 2nd and D will be 3rd. If its a manual and you put it in D it will be in 3rd never 1st. Im sure it has some type of shift kit but it seems like its shifting normally...ie...1st is 1st and D is 1st until you get to speed and need 2nd then 3rd. If it were me Id check the line because could be a vaccum leak but thats not something that just "happens." If its not clogged or disconnected Id drop the pan (17 bolts I think) change the filter and pull the valve body out. Its no big deal to do even with the tranny in the truck. Id blow the valve body out with some air and reinstall. I bet there is a small piece of grit stuck behind one of the little ***** that regulate the pressue and make the tranny shift.
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If you have a manual valve body 1st will be 1st 2nd will be 2nd and D will be 3rd. If its a manual and you put it in D it will be in 3rd never 1st. Im sure it has some type of shift kit but it seems like its shifting normally...ie...1st is 1st and D is 1st until you get to speed and need 2nd then 3rd. If it were me Id check the line because could be a vaccum leak but thats not something that just "happens." If its not clogged or disconnected Id drop the pan (17 bolts I think) change the filter and pull the valve body out. Its no big deal to do even with the tranny in the truck. Id blow the valve body out with some air and reinstall. I bet there is a small piece of grit stuck behind one of the little ***** that regulate the pressue and make the tranny shift.
this really didn't "just happen" its been happening since i got it but ive always got in into 3rd eventually...
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Hey I just noticed that I'm an elder user
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JR
Last edited by 76 F-150 390FE; Dec 18, 2007 at 07:02 PM.


