C4 tranny hurtin

[DirtyWhiteBoy]

Went to the farm I hunt decide to drive the bronco and exercise the 4wd. every worked fine until like most people From North Florida is said those infamous words
"Watch this" went back to two wheel and nailed it (justa little) from a roll.
Ye-haw nice power. then driving home it quivered trying to take off from the stop sign.
Well I adjusted the bands as discussed on many forums. No change it doesnt seem to be dropping into 1st gear from Drive. If I manually pull it back to first gear okay but otherwise not happening. Now if nayone is a tranny expert and has some advise I'm all ears. Tim (Dirtywhiteboy) witha sick C4

[broncosbybart]

Could be the vacuum modulator or the valve body having issues. I'm not a trans guru, so I can't offer more than that. My guess would be more of a valve body thing than the modulator.

[DirtyWhiteBoy]

I figured I replace the inexpensive items first. Put new vacuum lines on last year, from the steel line to the modulator and to the vacuum port on the intake. Will replace the modulator now. But I have located a local Zebulon Transmission man that everyone speaks highly of he said under $700 complete.
Lots better than what the Raleigh boys wanted..And he has a pile of classic cars around he likes restoring them too..

[chuzie]

It is not the vac. I would suspect the governor shuttle valve is stuck or less likely, a valve body issue. This prevents it from shifting all the way down to first and leaves you sort of in between 1st and 2nd until you give it enough power to force it to shift into first. This will eventually eat up the transmission if you allow it to continue. I suggest you keep shifting manually.

You can pull the transfer case off and observe the governor on the output shaft of the transmission. You can remove the bolts (2 or 4 i believe) and slide it off. You will see a large metal valve on one side. It should move freely under spring pressure.

This is usually caused by some sort of contamination in your system that the filter did not catch which leads me to wonder if this is secondary to a more pressing deterioration in the system like clutch or band material.

I would suggest you pull the pan and inspect the condition of the fluid and check for debris both in the pan and the filter. Also observe the smell and color of the fluid; should be red and not smell burnt. If that "pans" out pull the governor and have a shop take a look at it. They can clean it up and lap the valve for under $20.

How many miles since your last rebuild and last fluid change?

[DirtyWhiteBoy]

I service the trany over the summer, pan looked good slit film wiped off the bottom but nothing abnormal. The magnet was it decent shape no big fragments noticeable. I've probably put 4 -5 hundread miles on it sibce then. Previous owner kept records of everything and it was rebuilt bout 10 years ago. Pretty much leaning that way again, thinkin it time to rebuild.
Thanks

[DirtyWhiteBoy]

Well this afternoon I had a chance to get back on the Tranny, I read somewhere that the dual vacuum modulators arent the best and one forum said to unhook the small line and plug it off. So I did that after I had readusted the bands for the 10th time. But this time I decide to get out the old trusty vacuum gauge and just check around. Found that the carb had no vacuum at either port, Hmmmm so I replaced the gaskets and retried again no vacuum. Well I happen to have another carb that came with the engine so I stabbed it and low and behold 15 lbs at the ports. got it to idle pretty good and adjusted it for maximum vacuum pressure. hook up the advance and went for a ride. Well I am pleased to say not only did it shift pretty darn good the brakes work a hellofa lot better too. without a lot of pedal it seemed to run the shifts out a litle better than before and no flare was noticed. Hopefull it is a fix, and not temporary.
A little seat time will tell.
I'm just a Dirtywhiteboy.(with a smile)
Tim

[blazinchuck]

heck yeah!!!thats awesome cant wait to see it

[DirtyWhiteBoy]

Yeah, I was stoked...now gotta run it around some the neighbor down the street said I could use his trailer so if alls working well I will bring it to the M&G....

[blazinchuck]

awesome!

[chuzie]

Bad on me. I didnt consider you not having any vacuum source. Good on ya for figuring it out.

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