I recently started driving my 77 as my daily driver. Recently I've noticed an issue with shifting. After the truck is warm (driven about 10 miles) when I take off from a red light it shifts almost immediately and revs before it shifts again then it seems fine at speed. If I drop it into 2nd while sitting at the red light I can feel it engage and the RPM's drop slightly. Also it seems to take off better starting in 2nd then shifting to Drive.

I'm confused and in researching I'm going to try the band adjustment first then the modulator.

Any suggestions?? Thanks

EDIT: The transmission is not original it was rebuilt about 10 years ago. Also I changed the filter about 3 years ago and the fluid is fine. It's full, nice pink color, and not burned smelling at all.

 

I went to the transmission shop today and bought a new locknut, while I was there I was talking to the owner and he seemed pretty positive it's the modulator. So I went to Autozone and bought one. Hopefully I can get the modulator put on this evening after work and do the band adjustment Saturday.

 

I`m surprised none of the experts has given an opinion. I think that the intermediate band adjustment and/or the new modulator will solve at least one of your problems
Good luck.

 

Thanks, I hope so too. I didn't get to work on it last night, I doubt I'll be able to tonight too, so I'll just do it tomorrow morning.

I'll post back tomorrow with results.

 

Well after those to changes now I have no Drive no shifts nothing!! It barely takes off in first and when I manually shift up to second I can hear a terrible clunk! then if I try to go shift to Drive it just revs and I go no where!!!!

When backing the band adjustment out should there be tension on it? Cause when I get to about 3/4 of a turn backing it out it there is not tension on it all, I can turn it very easily with my fingers??? Could the band be broken?

I need some advice badly!!

 

Entirely possible something came loose. This may help: Small Block Ford Transmission Performance Band Diagram Photo 19

 

Thanks for the pic, I actually have that one already saved with the instructions I printed.

I'm guessing there's no easy way to tell if something did come loose, huh???

 

Drop the pan and valve body and have a look see.

 

I pulled the pan but I'm very apprehensive about taking that valve body out. I've done some searching and found information that says when reinstalling it that it has to be done by the manual, no guessing on the torque. I know the truck doesn't go right now but I don't want to seriously mess something up just trying to look at it.

 

Just make sure ya get the bolts back in the same hole and get them good and snug. If yer worried about it use a little lock tight. I have never used a torque wrench there and never had a prob. It is not that critical a place. Just don't snap one off as they need not be that tight. There is no stress or vibration there like there would be on a head bolt.

Did ya find any metal shavings or parts in the pan?

 

Ok I went ahead and pulled the Valve body. There were no big pieces in the pan, fluid in there did have a shimmer to it though like it had metallic dust in it. The trans was rebuilt about 10 years and I replaced the filter about 3 years ago. The filter is still clear I can see right through it.

On to the other. The indermediate band is floppy. I can move it with my hand very easily, but the reverse band is tight. Should the intermediate band be tight like the reverse? I would think so but I don't know.

 

I disagree. The valve body torque is critical. With the wrong torque you can easily strip a thread or warp the valve body. Get a torque wrench and do it right.

 

Since nothing was broken or laying in pan. I'm lost as to what's wrong. At least before I messed with it I could pretty much shift through the gears manually to get to 3rd. Now it won't go into 3rd at all and when I drop it in drive it acts like it's still in Neutral.

It seemed fine a couple weeks ago, out of the blue one day it just started shifting funny. Now I can't drive it all!

 

Any other suggestions or easy checks before I pull the transmission out and start taking it apart?

 

My guess is that if re tightening the band ya backed off don't help than the lining is gone on the clutch pac's. The shimmer you see is most likely clutch and band lining. The C4 is an easy trans to overhaul. The kit comes with instructions. That and a repair manual and most anyone that can do basic auto repair can do it without any fancy tools. I have done hundreds and never used a torque wrench. Just saying. But it wont hurt to use one or take it to AMCO.