C4 symptoms and thoughts...

I just bought a 1977 w/ a C4 that had a leak in one of the transmission lines. I ordered new lines from JBG, and while I was at it, I replaced the modulator with a green striper and put in a new filter and new fluid.

When the vehicle is cold, it shifts like it is nobody's business. It is smooth and finds all gears at the seemingly right time. As it starts to warm up, the shifting goes to crap. You have to get into the gas before the transmission catches and drives the truck forward (is that the definition of slipping?).

As for the history, the truck shifted before, but I was hesitant to run it before I changed the lines, so I never really got things warmed up...

Any thoughts? A quick search did not return any answers to me...

When the vehicle is all warmed up, how does it shift manually?
And is this condition you are feeling during the 2nd to 3rd gear transition.
Did you double check the fluid level when it was acting-up?
~BH~

BwoncoHowie said:

When the vehicle is all warmed up, how does it shift manually?
And is this condition you are feeling during the 2nd to 3rd gear transition.
Did you double check the fluid level when it was acting-up?
~BH~

Click to expand...

it shifts fine manually. i havent tested it in that capacity, but i did make a trip to the gas station a block from my house. as i turned up hill, i lost momentum go up the drive and mashed the go pedal with no forward movement. i then manually shifted into first and it took right off.

the fluid level seems fine, but i am just barely over the full mark.

If it falls out of gear going up hill, try adding another pint of fluid and test drive it again. Did you install the Bronco correct filter and sump tube?

went through the tranny again. correct filter with sump tube. correct spring with plunger on the top side of filter. correct amount of fluid.

after test driving it around the block, it did fine and shifted okay. it wanted to hold first gear if you stepped into it to down shift from second.

i actually put the truck on the road for the first time today and put about 30 miles on it. after the truck is warm, it wants to hold first gear and not upshift, no matter what gear you have the shifter pointed at. the only time i got it to shift out of 1st was after a long down hill. i accelerated, then let off of the gas, the truck continued to pick up speed after coasting, then when i gave it gas again, we had upshifted...

got the truck home, let it cool for a few hours, drove it again, and it worked flawlessly while cold.

another note: i am sure i feel first gear. what i dont feel is a difference between second and third. i had the truck moving at 70 MPH (stock tires and gears) and it didnt sound like it was revving, but i am not feeling a 2-3 shift, which makes me wonder if it is skipping a gear...

howie, come to my rescue!

tdc_worm said:

went through the tranny again. correct filter with sump tube. correct spring with plunger on the top side of filter. correct amount of fluid.

after test driving it around the block, it did fine and shifted okay. it wanted to hold first gear if you stepped into it to down shift from second.

i actually put the truck on the road for the first time today and put about 30 miles on it. after the truck is warm, it wants to hold first gear and not upshift, no matter what gear you have the shifter pointed at. the only time i got it to shift out of 1st was after a long down hill. i accelerated, then let off of the gas, the truck continued to pick up speed after coasting, then when i gave it gas again, we had upshifted...

got the truck home, let it cool for a few hours, drove it again, and it worked flawlessly while cold.

another note: i am sure i feel first gear. what i dont feel is a difference between second and third. i had the truck moving at 70 MPH (stock tires and gears) and it didnt sound like it was revving, but i am not feeling a 2-3 shift, which makes me wonder if it is skipping a gear...

howie, come to my rescue!

Click to expand...

Have you tried adjusting the front band yet?

BwoncoHowie said:

Have you tried adjusting the front band yet?

Click to expand...

that sounds like a graduate level question, and the short answer is no. is there a tech article anywhere that could walk me through or describe that to me? thanks!

tdc_worm said:

that sounds like a graduate level question, and the short answer is no. is there a tech article anywhere that could walk me through or describe that to me? thanks!

Click to expand...

okay, so it isnt graduate level stuff. i figured out how to do it. i did, however, manage to turn the adjusting screw all of the way in so no threads were exposed with just my fingers...no resistance. i am gonna go with that aint good. i smell a rebuild in my near future...

tdc_worm said:

okay, so it isnt graduate level stuff. i figured out how to do it. i did, however, manage to turn the adjusting screw all of the way in so no threads were exposed with just my fingers...no resistance. i am gonna go with that aint good. i smell a rebuild in my near future...

Click to expand...

Your front band is probably broken, Drop the pan and Valve Body to verify...