c6 2nd to 3rd run up

[oldtoyist]

I have a 72 Ranchero with a built big block and c6. Transmission has about 12thousand on it. Between 2nd and 3rd, it revs before going into gear. Would a servo kit solve that?

[basketcase0302]

Oldtoyist,
Stop by the welcome mat when you get a chance:
http://www.fordification.com/forum/viewforum.php?f=1
Hopefully Bobby or Donnie or someone else here can answer your C-6 question soon.
Did you know there is a forum on the Chero':
http://www.ranchero.us/forums/

[Donnie]

A servo could possibly help, but there may be other things to consider ..First off the 2-3 shift is a timed shift, that is the 2nd gear band is holding the drum where the 3rd / rev clutches are located. The oel that applies the 3rd clutch also releases the 2nd gear band....So it is possible that there is a problem in the servo... For 3rd to come on these clutches need to apply fast & then the drums are locked together & you are in direct drive...input & output shafts are connected together and the planetary gears are just free wheeling ==3rd gear
A few questions:
How is the REV apply, is it fast & firm.......reason for asking...the same clutch pack is used in rev, if rev is soft or slow, you may have worn clutches...... or a problem in this drum.do this test
Also there is a triangle cast into the servo cover...one of the sections has a large letter cast into it....... it is by itself & LARGE..what is it?
How does the fluid look? & smell?
Does this happen of a soft driveaway...or on a hard throttle driveaway? or does it not matter?
Also check your kickdown rod for binding or not returning....Make sure that it returns by itself...check motor mounts..
Has anyone worked on the valvebody? A reprogram kit, perhaps? Is 2nd gear firm & ON TIME?..Is the shift to 3RD on time or early or late, I know that it is slipping, but is it happening when you think it should? I assume you have checked your vacuum system.
These are a few things that come to mind........Bobby or others may chirp in with other ideas
The questions that I asked will help us to locate your problem...............Donnie

[Aussie_1970]

Does a C6 have a vacuum modulator like a C4? Reason I ask is that my C4 would rev between changes from 1-2 and 2-3. turned out that the vac pipe to the modulator was perished. I suppose if it changes fine between 1-2 it may not be this, but thought I would chime! Apologies in advance if Im way off

[oldtoyist]

Thanks for your replies. Checked the kickdown and it was free. Drove it hard this morning while it was warming up, and it shifted strong and on time. When the transmission warms up, 1st to 2nd is strong, but it revs between 2nd and 3rd. If I nail it, revs less. Reverse is strong. Have a picture of the servo cover. Had a guy rebuild it about 12,000 ago and was suppose to include a shift kit. Have never been real satisfied. Thanks

[Donnie]

I may be wrong on this but, my best guess from experience when I found this condition was mostly related to the rev / hi drum... If you eliminate all other possibilities, the rev/ hi drum could be your problem, either ring wear on the delivery section of the front pump, too much end play, the drum is cut from the rings, the bushing in the drum is worn, or bad seals in the drum piston (leakage), piston check ball not seating.
If you think or get another opinion same as mine, write back & I can tell you how to air test for a leak in this drum..
It will require a pan drop & valve body removal, if you have basic mechanical skills........I will walk you thru the test,, You will need air...

The rev apply that I mentioned is not really a valid test as the pressure is boosted a lot in rev.
The pressure also is related to how hard you are into the throttle...There could be other reasons for a soggy 3rd, but this was always the most common one that I found with the symptoms that you have mentioned.

Bobby Ford may have another suggestion.......Some times I go too deep, but this is what I mostly found. Since you never had a good third, there could be a valve body problem, too....the easy check is the drop pan air test.............Donnie