Widow_maker89

I have a 1994 lt1 4l60e z with an interesting problem... when you first take off after starting the car first gear engages after it shifts to second the first time it wont go back to first not even manually...it has no overdrive it does have a brand new shift "A" solenoid. The car will not down shift either and no ses light

Billy Biker

Have you did any pcm changes that might have affected the shift points ect?
I'm still coming to grips with the fact a computer controls the shifting on these cars, not vacuum diaphrams and kick-down linkages ect I noticed with my hypertech programmer if a person wanted to they could wreak all kinds of havoc with an auto

Widow_maker89

I just bought the car. It needs a front clip and the trans problem fixed. A seventeen year old kid hit a pole. But as far as that goes...Car looks/ sounds/ and seems bone stock minus the flowmaster exhaust it is in limp mode, IE 2,3 only it has a new 1-2 "A" solenoid in it and power to the transmission and from what i can tell with a continuity test to the frame a good ground, i guess i have to try to find someone to scan it.. it was manufactured on 1/04 and like i said lt1/4l60e has plenty of power the first time you take off is in first and the 1,2 shift is crisp and clean the 2,3 is as well but no downshift first or fourth cause of the limp mode, I have no ses light on cusious what the troubleshooting or diag steps would be thanks again Matt

Widow_maker89

more info the trans will engine brake in 2/d but if i select OD it just free wheels.... i left the battery disconnected overnight and it worked for about 2 blocks downshifting and all

xtremetrans

You need to scan the car to see if any codes are present

Widow_maker89

I have had a total of three codes ONE was trans over temp79 maybe? then i cleared the computer and drove today i got cod i belive 59 trans under temp and code 84 3-2 downshift solenoid feedback fault. It takes off in first put into 2 and it hold rpms till an appropriate shift point put in 3 and hold rpm till an appropriate shift point no put in od and no shift. in 3 it will engine brake in od it will not... other oddities incase it helps.... High beam indicator on dash will illuminate but the low beams stay on no change outside... if i get hard on it in first before it shift to secont the air bag light will flash untill i let off i can not cross therminals "A" and "B" to flash codes the local GM dealership says i should be able to do that according to mitchell on demand"auto program" i should be able to... and according to their tests my ecm is bad but if they say i should be able to cross the terminals and i cant then im not sure how much i trust the rest of the info... I have scanned it with a GENISIS a snap on brick and a snap on motis and all three have no issues reading or communicating with the pcm... I have seen several post on ignition switch failures i have power to the transmission not sure about the grounds.. I am a little curious if this sound ike the potential problem I ran out of gas one day tried cranking it for a while, when i got gas in it again and took off the trans worked perfectly for about 3 miles then back to normal.... any help anyone could give me would be great...

Widow_maker89

If i clear the codes with a genisis while i am driving it goes into od fine and will drive just fine even go into first when i stop... if i make is downshift with the throttle or turn the ignition off it will come back to the code 84 3-2 downshift fault... the trans now has a new 3-2 solenoid

Performabuilt

Since yo changed the solenoid I would say that you have and issue with either the trans internal harness or the actual connector to the trans not making contact , The reason it . sets limp when you first start it is the self test every solenoid is turned on briefly , Now when your going down the road and clear there is no self test, and that solenoid does not come on until you do a forced kickdown 3-2 then its comanded on and the code sets again, Its going to be a wiring or terminal plug issue

Widow_maker89

Thank you for the input but we have a slight mis understanding either on my part or yours... If i clear the codes when im over say... ten mils an hour it will drive perfect upshift downshift even all the way to first as long as i dont drop below 15 it is good basically as far as i can tell it only faults when it is supposed to return to first with out throttle... The tps is properly adjusted.. just at a loss maybe i will have to go to a six speed manual... oh yea am i supposed to be able to cross a and be for diag on a 94 cause i cant...and can just the transmission part of the computer go bad?

Performabuilt

Looking back over your symptoms you have only a few possibilities, Either there is still some issue with the shift solenoid A or the 1-2 shift valve itself "rare", The 1-2 accumulator piston could be leaking causing the modulated line behind it to apply the second servo. Of even possibly some issue with the servo itself. Now another possibility I have seen in a few trucks but not cars is a bad ignition switch it will feed low voltage to the trans and set weird codes and cause 2nd gear starts because theres not enough voltage present to properly apply the solenoids.

Widow_maker89

thanks for all the great imput now to go in for the kill..... it throws a code 84 3-2 downshift feedback fault only on the 1-2 upshift after coming to a stop, maybe someone has had this problem or someone with considerable experience can tell me what i have going on

Widow_maker89

ok after data logging and review this is exactly what is happening, I get a 3-2 downshift error on my 1-2 upshift on non WOT shifts any help would be great thanks guys

Performabuilt

I would change the 3-2 solenoid then

Widow_maker89

lol it has a new shift a solenoid, 3-2 shift solenoid fluid and filter... anyone want to buy a 94 z with an odd trans problem and some front end damage (i bought it that way)

Performabuilt

Check over wiring then both external and trans internal