1993 auto trans wouldn't shift from 1st: you'll never guess what was the problem!!
10-12-2010, 09:23 PM
#1
Le Mans Master
Thread Starter
1993 auto trans wouldn't shift from 1st: you'll never guess what was the problem!!
So I've been dealing with a serious transmission problem, it wouldn't shift out of first!! I had tried re-setting the TV cable with the factory procedure 3 times, no dice. As you may know; 1993's have a complex TV cable setting procedure because of the TV cable, throttle cable, AND cruise control linkages all being intermeshed. It involves a torque wrench reading inch-lbs, drill bits, yada yada...
When I set it the last time; I noticed the cruise control actuator had a big hole in the rubber diaphragm/bellows thing (looked like a mouse/rat chewed it).
I decided to replace it; it needed replacing obviously in this condition, plus I was curious that it might be interfering with the TV cable since the cable from the actuator integrates with the TV. Not expensive, ~$100 from Advance with a $30 online discount.
I replaced it in <5 min... the car shifts fine!!
I guess the moral is, when diagnosing a shifting problem on a 1993 Corvette w/700r4k, check the cruise control components.
When I set it the last time; I noticed the cruise control actuator had a big hole in the rubber diaphragm/bellows thing (looked like a mouse/rat chewed it).
I decided to replace it; it needed replacing obviously in this condition, plus I was curious that it might be interfering with the TV cable since the cable from the actuator integrates with the TV. Not expensive, ~$100 from Advance with a $30 online discount.
I replaced it in <5 min... the car shifts fine!!
I guess the moral is, when diagnosing a shifting problem on a 1993 Corvette w/700r4k, check the cruise control components.
before its time for storage,like I have to do to mine
This may be helpful to someone in the future
10-17-2010, 05:40 PM
#5
Burning Brakes
Member Since: Apr 2009
Location: Broken Arrow Oklahoma
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All of the early GM transmissions used vac. to control the shift.
Modulator valve.
I haven't looked at mine to see if it even has one.
I was in the business back in the mid 70's
The turbo 350 kept us all in business for years.
Modulator valve.
I haven't looked at mine to see if it even has one.
I was in the business back in the mid 70's
The turbo 350 kept us all in business for years.
10-17-2010, 10:41 PM
#6
the 4L60/700R4 from 1993 does not use vacuum for anything. The TV cable is a cable that operates a throttle valve which adjusts the pressure to the transmission.
My guess is something else was missing. The cruise control has nothing to do with shifting, even though there is a few cables going into the ASR, they all adjust throttle for ASR and cruise control to modulate speed etc.
But, since I will probably get flamed for this, ask PETEK.
I bet the cruise control cable was misaligned and when you reinstalled the vacuum diaghram you fixed the cable for the cruise, which goes in the ASR module.
My guess is something else was missing. The cruise control has nothing to do with shifting, even though there is a few cables going into the ASR, they all adjust throttle for ASR and cruise control to modulate speed etc.
But, since I will probably get flamed for this, ask PETEK.
I bet the cruise control cable was misaligned and when you reinstalled the vacuum diaghram you fixed the cable for the cruise, which goes in the ASR module.
