C4 won't shift into 3rd gear when cold

(edit)

Okay, Paul. I finally had a free night to tear into my C4 and I found a layer of dark gray silt about 1/16" deep in the pan, it was also all through the filter and valve body. The insides look clean otherwise and did not smell burnt at all. The fluid was reasonably clean, despite the layer of gray silt on the bottom of the pan and in the valve body. So is this a bad sign or normal for a trans in need of a fluid and filter change? The transmission shifts nice and firm after it warms up and seems to have no other issues other than not shifting into third gear when it's cold. I've cleaned everything, should I go ahead and reassemble it or is this a sign of impending terminal failure?

Second question. When I took apart the valve body, I tried to be careful not to drop the check balls out before I could see where they go... well you know what happened next so I know one goes where the red circle is below.... but where does the other ball goes?

Yes the red circle is ok for 1 checkball,there is a similar pocket in the top valve section for the other .. I'll dig up pics if you need ..
You will get some buildup in the pan if not been serviced for a while. If it is just a film i'd say ok , but if it is chunky and infact 1/16" thick i'd be concerned. At this stage prob be ok to ensure all the VB is free and clean and try it. Were the shift valves all free?

Thanks Gregaust, I have been busy and haven't been here for a couple of days.

There is another passage in the other half similar to the one you show in the red circle. Those are the only two you have to worry about.
Clean the gray residue out with clean solvent and a brush or a can of brake parts cleaner, lube the valves with ATF and make sure that they are not scored. You can polish them in the drill with 400 or 600 grit emery paper with some ATF on it. be sure to clean the valves after polishing and lube them when you install them. Check for broken springs and sticky bores while you are there.

Thanks for the quick replies. The valves are all free and judging by the case (clean) and the drums (not scored) I don't think it's been more than a few 1000 since this transmission was rebuilt. The silt was pretty alarming. After I dumped the oil from the pan, I took my finger and scooped it from the bottom of the pan. It was fine granular goo about the consistancy of mud. Everything washed up easy with brake cleaner (what doesn't? lol) and is waiting reassembly *if* I can find the right filter.

Okay, I have rebuilt the valve body and it still will not shift into third gear until it is driven for a mile or so in second gear. I'm going to buy a new valve body from broader performance next and see if that fixes the problem.

Another problem has emerged; when I do a redline throttle pass up through the gears the trans dipstick pops out about 2" sometimes (not all the time). What could be causing this pressure? And is it related?

Tell me that you have reverse gear when the transmission is cold - the same clutch is used for reverse and High gear. If you have reverse but no high gear then it is the valve body (probably the kit that was installed) or a linkage adjustment problem. The dipstick popping out could be a result of the problem but I would look at the vent first. Make sure it is not plugged or stuck closed with paint. The top of the vent should wobble freely.
Check the fluid level with the engine idling in Park.
Let me know what you find.

Originally Posted by PaulS1950

Tell me that you have reverse gear when the transmission is cold - the same clutch is used for reverse and High gear. If you have reverse but no high gear then it is the valve body (probably the kit that was installed) or a linkage adjustment problem. The dipstick popping out could be a result of the problem but I would look at the vent first. Make sure it is not plugged or stuck closed with paint. The top of the vent should wobble freely.
Check the fluid level with the engine idling in Park.
Let me know what you find.

Hi Paul. Buried somewhere in this thread, reverse gear drops in firmly and does not slip when cold. Rebuilding the old VB helped. I'm pretty confident the new broader performance valve body will fix the shift problem. What does worry me is the amount of silt that was in the pan and all through the insides of the ruined valve body. The tranny shows no weakness and it shifts firm after it warms up for a mile. I'm hoping we fix it up. Summer cruising season is here and I can't afford to buy a new Transmission right now.

The stuff you see in the bottom of the pan is common. It is probably from the initial wear in of the bands and clutches. I doubt you have done much damage as long as the fluid doesn't show any sign of burning. You said it was still bright red so I wouldn't worry about the residue in the pan.

Hey Paul,

I installed some new parts and have some new problems :\ since this seems to be my ongoing tranny problem thread, I figured I'd just post the "progress" and problems here for you to continue your advice.

The parts I installed are:

TCI street fighter series manual/automatic VB
TCI white stripe screw in modulator
Lokar kickdown linkage (previously had no linkage)

When I took it out for the first test drive i noticed right away that just cruising the trans felt more squishy then it did before. so anyway, i get it out onto the main drag where the speed limit is only 40 and lots of traffic lights. i had it in drive to see how it would shift up through the gears by itself. first to second came a little higher rpm than it did before, probably because the modulator is screwed in a few more turns. then when it got to third - it free revved - and i thought, crap! no way! so i goosed the throttle a bit and it dropped into third gear. okay, that's not right, but a lot better than it was before. i came to the next light and it shifted properly by itself all the way to third. i gave it a few miles to get the valves broken in before i tested the kick down. so i'm driving along at about 30 mph in third gear at about 1500 rpm and i start pressing the gas down slowly, more and more, until i get it 3/4 down and the thing suddenly leaps into first gear and then takes off like a bat out of hell (not what i was expecting!) luckily nothing was in front of me for the suprise holeshot! anyway i gathered it up and returned to a cruise around 35 mph and squeezed the pedal down about 1/2 looking for a second gear kickdown and it just kept lugging until i pushed it down more and again it leaped into first gear. when it does this it tachs to about 5 grand in first, right past second, then it goes a ways and shifts into second gear. so i go back and make sure the cable is adjusted; when the throttle is wide open the kickdown cable is right at the end of its mechanical travel with just a tad extra slack to not bind the mechanism. so i go back out for another test drive and this time i'm going to go hard up through the gears in drive; first-second barks the tires firmly at 5 grand, but when it goes to shift into third at full throttle it suddenly feels like there is some sort of drag and the motor is straining just to maintain rpm at wide open throttle. so i got out of the throttle right away because it was a very strange feeling; like i had the brakes on while flooring it in third gear. so i just cruised it a few miles through stop and go red light BLVD cruising and when i got it closer to home I tried hopping on it from a stop; when it got to third gear under heavy throttle it felt like i had the brakes on. i slowed a bit and it seemed to cruise okay in third. So I decided to slow down and I manually dropped it into second gear so i could hop on it in second and it pulled great from 2000 rpm to 5500 in second gear. I didn't try third gear again, it seemed something was not right, so i just eased it back on home as I did not want to damage anything.

What should I do next, boss?