4l60e gurus please help
4l60e gurus please help Background. Car worked great all last year. Added a little power, took out a little weight, changed fluids this spring and just got the car together last Friday. Wouldn't shift to 3rd at WOT at all Saturday until I let off of the go pedal. Had Sean at C.A.R.S. touch up the shift points and do a sim pull on the dyno to see if it worked OK, it did.
Went to the track at Stanton,MI last night and 2 of 5 passes it shifted.
1st pass right out of the trailer, 25 psi in the rears, spun to a 1.69 60' and ran an 11.51 @ 120ish.
2nd pass after dropping the tires to 23 psi from the 27 that they had climbed to, 1.55 60' no shift to third. WTF
3rd pass after a long cool down to see if it was temp related, dropped the tires to 21 psi cold, 1.51 60' no shift to 3rd again.
So I went right from the ticket booth out onto the street and ran up to the next little town slowing and speeding up and ramming on it in 3rd to see if it was the 3-4 clutch pack going out. Pulled hard in third with no signs of slippage. On the way back I slowed to 30 a couple of times dropping the shifter into second so that it would hold second, nailed it then pushing the lever to third and it shifted fine, right when it was supposed to.
When I got back to the track I went right up and ran a pass. 1.51 60' 11.12 @ 120.73.
Let it cool down for a bit and went for pass number 5. 1.507 60' and no shift to 3rd.
Is there anything in the PCM that would cause an intermittent problem like this?
I'm thinking no and looking towards a bad 2-3 shift solenoid in the trans.
Any helpful hints will be greatly appreciated.
Went to the track at Stanton,MI last night and 2 of 5 passes it shifted.
1st pass right out of the trailer, 25 psi in the rears, spun to a 1.69 60' and ran an 11.51 @ 120ish.
2nd pass after dropping the tires to 23 psi from the 27 that they had climbed to, 1.55 60' no shift to third. WTF
3rd pass after a long cool down to see if it was temp related, dropped the tires to 21 psi cold, 1.51 60' no shift to 3rd again.
So I went right from the ticket booth out onto the street and ran up to the next little town slowing and speeding up and ramming on it in 3rd to see if it was the 3-4 clutch pack going out. Pulled hard in third with no signs of slippage. On the way back I slowed to 30 a couple of times dropping the shifter into second so that it would hold second, nailed it then pushing the lever to third and it shifted fine, right when it was supposed to.
When I got back to the track I went right up and ran a pass. 1.51 60' 11.12 @ 120.73.
Let it cool down for a bit and went for pass number 5. 1.507 60' and no shift to 3rd.
Is there anything in the PCM that would cause an intermittent problem like this?
I'm thinking no and looking towards a bad 2-3 shift solenoid in the trans.
Any helpful hints will be greatly appreciated.
Imtermitant issue thats temperature dependant could be a 2-3 solenoid but because there are so many other factors besides just shift tables that determine when a shift happens it also could be tuning replated. I would suggest taking a scanner or tuner with you next time and try to make a movie or watch what the PCM is comanding.
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I have seen this occasionally, when with a fairly good 60 foot time, the transmission filter opening can get uncovered, allowing air to get in the system, and this can cause your problem. Most of the time adding about 1/2 - 2/3 quart will solve this.
1/2 quart should not hurt anything .
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