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Long Winded Shifts

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13K views 29 replies 16 participants last post by  87vette70TA  
#1 ·
This is something I've asked about before but it didn't really go too far... so here it is again. Under moderate to heavy acceleration, the shift from 1st to 2nd gear is kinda harsh. (I have an automatic) Especially under heavy acceleration! It seems as if first gear is too long... like you can hear and feel it accelerate great and then it just stays....stays....stays.... and finally *BAM* *JERK* it shoves into second and goes right on it's way! This can't be a normal C4 auto thing can it? I could tell that if the trans didn't do this "pause and jerk" thing, that'd it'd be a significant gain. Any ideas?
Thanks in advance
-Dan
 
#2 ·
The Vacuum Modulator controls A/T line pressure by sensing variations in engine torque.

A defective VM can cause:
Harsh up/downshifts
Delayed upshifts
Soft up/downshifts
Slips in L, D, R
Trans overheating
ENG burning trans fluid

Vaccum Diaphram Check:
Turn Modulator so vacuum connector faces DOWN
If any liquid drains out, REPLACE

Atmospheric Leak Check:
Apply soap solution to vacuum connector & crimp seam
Attach short piece of hose to vacuum connector
Blow <6psi into hose and check for leaks (air bubbles)

Load Check:
Install a known good modulator of the same type on one side of tool J-24466.
Install the modulator to be tested on the other side.
With ASSY level, slowly push the two modulators together:

If the gauge line remains BLUE, REPLACE the modulator.
If the gauge line is WHITE, the modulator is O.K.

Sleeve Alignment Check:
Roll modulator on a flat surface. Ob's the sleeve for concentricity with the modulator can.
Check plunger for free movement.

Causes of Improper Vacuum at Modulator:
ENG Tune Up
Loose vacuum fittings or improper routing of hose/lines
Vacuum operated ACC leaks (hoses/valves)
Exhaust restrictions
Restricted or incorrect vacuum line to modulator size orifice
Carbon build up at modulator vacuum fitting
Pinched line
Grease in line (delayed or no upshift-cold)

[CSM, 1984, 7A-4]
 
#3 ·
***War Machine's reply***

Hey DBow!!

How long has this been doing that?

If it's been since you bought the car I'd say the TV cable is in too far. If you don't know what the TV cable is or how to adjust it I'll explain it here. If you do know, skip to the next paragraph. The TV cable is the one that runs through a housing that had a "D" shaped tab on it mounted near the throttle body. To adjust it automatically, push the tab in and the needle will go all the way in. Press the accelerator pedal to set it automatically. To set manually, press the tab and pull the needle out by hand. The needle has teeth on the bottom of it so you might hear clicks. I have mine set to 4 clicks from all the way in. I get WOT shifts from 1st to 2nd at about 5200, 2nd to 3rd at 5000, and 3rd to 4th at 4800.

If you have it set all the way in, you'll shift at about 5800 which is WAY too long for a stocker. For every click you let it out, it decreases the shift points by 200 rpm's. If you're intake manifold, runners and plenum are all stock, you should set it at about 4800 or 5000 prms in 1st gear. The stock TPI hp peaks at around 4400 rpm's.

Give that a try and let me know how it goes.

-John
 
#7 ·
War Machine,
I adjusted my TV cable and.......... SUCCESS! I did a run around town with a hand full of "complete stop and then GUN IT" runs and my neck stayed right where I put it. The 1st-2nd shift was firm but not by any means what it was like. When just putt'n around, 1st-2nd shifts were nearly un-noticed (even with the radio off).

I am going to do some more driving later today and will get a much better idea of the difference I've got but so far, it looks REAL good.

MOVE OUTTA THE WAY!!!!!! :devil: :devil: :devil:
 
#9 ·
Hey, that's good to hear DBow! :partyon: :cheers:

Just think of the extra gas milage you'll be getting by not reving it so high. :thumbsup:

I had my trans beefed up to handle 425 rwhp when I lost 3rd and 4th gear last year. I went out one day to test the porting I did of the TPI intake. I set the cable to 5800 rpm's so I can feel when the power dropped off. When I shifted from 1 to 2 under normal acceleration, the shift's kicked so hard I thought John Henry was blasting at my drivetrain. :laughing:

Image
 
#10 ·
War Machine said:
Hey, that's good to hear DBow! :partyon: :cheers:

When I shifted from 1 to 2 under normal acceleration, the shift's kicked so hard I thought John Henry was blasting at my drivetrain. :laughing:
Click to expand...


Yea, my book even talked in depth about the TV cable and how if it's just a little bit out of range you could easily think your trans is broken or something worse... go figure, a little cable adjustment.

I may tweak a little more just to get my exact desire. The hardest part is, my tach isn't currently working so I have to feel and listen to the transmission sing/shift.

:cheers:
 
#20 ·
use your foot

if you want to just listing to roar let of a little matt it again or shift it manually wtf lol:nuts: and these c4 run so freging hot no matter what out today had to let it cool down it was so hot the starter baulked on me lol waited ten minutes lifted hood up and it fired up :smack
 
#11 ·
We've had a couple customers come to PHP w/ what they thought was a trans problem and it turned out to be the TV cable. We didn't even charge those customers for the adjustment b/c it takes just a minute or 2.

Since you don't have a working tach, this might help you out. What I did to mine is this, I got a knife :surprised no, this isn't going where you think it's going. :laughing: I pulled the slider rod out one click at a time and made a notch on the rod w/ the knife at every click. Knowing that "full in" was 5800 and every click "out" was a 200 rpm decrease, I just counted the notches. You'll want it to be 5 notches "out". Compare that to how many notches it pulls out doing the auto adjust. I'm pretty sure mine pulled out 4 or 5 notches when I auto adjusted it.
 
P
#12 ·
I was experiencing this same problem over the weekend. I thought I was having a problem with my trans. When I read this tread I checked the TV cable and found it was pushed all the way in also. With War Machines post I was able to fix it and have not experienced the problem since. Thanks for the fix.
 
#13 ·
packles said:
I was experiencing this same problem over the weekend. I thought I was having a problem with my trans. When I read this tread I checked the TV cable and found it was pushed all the way in also. With War Machines post I was able to fix it and have not experienced the problem since. Thanks for the fix.
Click to expand...
Awesome! War Machine helped 2 Tiger's fans in one week!

:partyon:
 
#16 ·
fatherinlaws said:
im gonna go try this right now
ill post again if anyone cares.
Click to expand...
We certainly do! Let us know.

I saw a brief article in my TPIS book that showed their changes in time they had by bringing the shift point down. Several tenths can be shaved off, and it's feel much better to get rid of that giant gap between gears.
 
C
#17 ·
didnt get it

ive located the Throttle position sensor, the throttle, the cruise throttle and one other cable in a cluster with the main and cruise throttles, but none seems to be the part spoken of. anyone have a pick of this thing or just a better description and location for me? im working on a stock 91.
 
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#19 ·
yeah i was looking at that one

THANKS for the pic RAIDMAGIC at least i know im not a complete moron, i did find the thing but its good to be sure. its on the throttle return cable, name? but it pulls the throttle back down when you let off. only trouble is i didnt find any needle and the cable itself wont stay when i push on the tab then pull the cable. any suggestions on replacing the piece or maybe im not looking for the right "needle" to adjust on it. the end facing me, from the pic angle there, is where i found a spring loaded deal to push, not a tab so much as the entire guts of the little device that cable runs thru.
 
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#26 ·
Caretaker said:
THANKS for the pic RAIDMAGIC at least i know im not a complete moron, i did find the thing but its good to be sure. its on the throttle return cable, name? but it pulls the throttle back down when you let off. only trouble is i didnt find any needle and the cable itself wont stay when i push on the tab then pull the cable. any suggestions on replacing the piece or maybe im not looking for the right "needle" to adjust on it. the end facing me, from the pic angle there, is where i found a spring loaded deal to push, not a tab so much as the entire guts of the little device that cable runs thru.
Click to expand...
Engine off, with your right hand thumb, push in the D shape tab and hold, then with your left hand finger nail push in the small black thingy surrounding the wire into the "tab housing".

Release the D tab, now it should hold the small black doody in.
Now open the throttle lever on the throttle body to WOT, whil you do that you will observe some "obstruction", don´t mind it, just continue till it has clicked a few times, could be four times.
Take it for a drive and see how it shifts.
 
#22 ·
i realize this thread is a bit old, but how do you adjust the tv cable on an 84? i dont have any D shaped parts, just a little square click-in cable and thats pretty much it. to me the car shifts way too early, under lights throttle, it doesnt let the engine wind up enough before it shifts and keeps the motor bogged down. on the contrary, it seems to take forever to shift out of first occasionally. however, i do have a B&M transpak installed...

any thoughts?
 
#25 ·
I was having a problem with mine shifting out of 1st. It turned out to be the governor. After fixing that problem then it started shifting to early. I adjusted the TV cable but it still wasn't right. I bought the B&M shift kit "the 2 stage kit...RV or street and strip" I set it up with the street and strip set up. It helped but still wasn't quite right. After some research I discovered the throttle pressure spring was weak. I replaced that one spring located in the throttle pressure valve and BINGO my tranny was fixed. Now it will bark the tires going into second gear every time I lean on the throttle. And it shifts at the same RPM every time.:thumbsup:
 
#24 ·
I wasn't to sure about how to adjust mine, this would have helped allot. I took mine to my local transmission god and he adjusted mine and didn't even charge me.. Now I know so it's easy....
 
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#27 ·
Tv cable , possibly !!

Ok , I am back. Drove the car to the car show over the weekend and what is happening is it seems like it is shifting into drive to quick. I have had the car since new and never have done anyhting to this cable to cause any issues that I know of. My tranny is the 4L60 . So what I am having to do is to keep in second and drive around unless I am on the interstate or running 50-+ mph. If not once it goes into drive , it starts jumping and all sorts of things, line mentioned, like it is shifting to quick to drive, any suggestions , I keep going back and forth. I took the cover off the servo unit and all the holes are lined up on the pullies and can stick a drill bit thru them all if that means anyhting . Now my cable has a tab on it that unloacks, but I have not done anything here either, need help if anyone has and opinion on this. Thanks Joe
 
#28 ·
REDVETTE1993 said:
Ok , I am back. Drove the car to the car show over the weekend and what is happening is it seems like it is shifting into drive to quick. I have had the car since new and never have done anyhting to this cable to cause any issues that I know of. My tranny is the 4L60 . So what I am having to do is to keep in second and drive around unless I am on the interstate or running 50-+ mph. If not once it goes into drive , it starts jumping and all sorts of things, line mentioned, like it is shifting to quick to drive, any suggestions , I keep going back and forth. I took the cover off the servo unit and all the holes are lined up on the pullies and can stick a drill bit thru them all if that means anyhting . Now my cable has a tab on it that unloacks, but I have not done anything here either, need help if anyone has and opinion on this. Thanks Joe
Click to expand...
The pulley Deal is the traction control throttle device.
Is the transmission fluid still clean & Cherry Red ?
Does it smell burnt or Brown & Black metallic gunk in it ?
Raid shows & telks how to Adjust the Transmission TV Cable above.
The Governor in your 4L60 (1993 C4 700R4) may be defective.
Hung up the Sliding shuttle valve with dirt, gummy deposits, & normal wear clutch pack material & the friction steels wear sending fine dust into the ATF.
There are screens for governor oil feed passages that can plug shut too.
Remove valvebody to clean out governor feed screens or replace them.
I have sucessfully cleaned 700R4 Shift governors with Carburator cleaner & 150 psi Shop Air blow gun.
 
#30 ·
roc757 said:
my 89 was doing the same thing in the fall , I thought it was trans for sure and I am in the process of installing the new trans right now , sure wish I would have joined this site before I got into this massive under taking
Click to expand...
Yes I know C4 700R4's & 4L60E transmissions very well.
Inside out.

Trans of choice for a long time till recent Horsepower Drag wars again.
Excellent transmissions for daily use & moderate performance use.
Powerful 1-2 upshifts From C4 & C5 autos kept owners happy for a long time.

Wise to rebuild because 1989 was a long time ago now.
 
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