HELP! 4L60e lost over-drive!
09-17-2011, 12:11 PM
#1
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HELP! 4L60e lost over-drive! Aw, come on! This has been a terrible year for my Zs!
I was driving the 'vertible to work the other day, when all of a sudden it dropped out of over-drive at about 65 mph. I tried manually shifting it to drive & back to OD, but it stays in drive now!
Took it to a shop (mechanics not necessarily trannys) & they hooked a SnapOn scanner to it & had me drive it 10 minutes. It shows that the shifter is in OD, the signal shows that it should be in OD, but it stays in 3rd gear...
Also, I HAVE to drive it right now, since I blew my motor in the other one, so I'm wondering how long before I totally destroy my tranny. It doesn't seem to be locking-up the convertor, & it's taching about 2400 at 60ish.
Anyone know what I can do to get my OD back?
Thanks!
I was driving the 'vertible to work the other day, when all of a sudden it dropped out of over-drive at about 65 mph. I tried manually shifting it to drive & back to OD, but it stays in drive now!
Took it to a shop (mechanics not necessarily trannys) & they hooked a SnapOn scanner to it & had me drive it 10 minutes. It shows that the shifter is in OD, the signal shows that it should be in OD, but it stays in 3rd gear...
Also, I HAVE to drive it right now, since I blew my motor in the other one, so I'm wondering how long before I totally destroy my tranny. It doesn't seem to be locking-up the convertor, & it's taching about 2400 at 60ish.
Anyone know what I can do to get my OD back?
Thanks!
Sorry I couldnt be of any help. 
09-17-2011, 09:34 PM
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My SS did the same thing when I got it back.. then a few days later it would be okay... then it just stayed in third all the time and then the stall came unbolted..
09-19-2011, 08:46 PM
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[QUOTE=jimmyblue;15402398]You say it isn't locked, do you see any slip codes? Or have a crazy trans
fluid temp that would inhibit lockup?[/QUOTE
+1 Also, are u sure it's not starting off in 2nd gear as well? That would be a simple fix replacing a shift solenoid. Other causes would be the #8 checkball embeded into the separator plate (no 4th only) and the seal on the outer-most piston behind the 2-4 servo cover.
fluid temp that would inhibit lockup?[/QUOTE
+1 Also, are u sure it's not starting off in 2nd gear as well? That would be a simple fix replacing a shift solenoid. Other causes would be the #8 checkball embeded into the separator plate (no 4th only) and the seal on the outer-most piston behind the 2-4 servo cover.
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09-19-2011, 09:34 PM
#8
1st of all... don't listen to the wisecrack comments. You need facts, and you brought more to the table here than most guys do in their first post. 1st gear and 2nd gear have nothing to do with the 4l60e being able to accomplish a 3/4 upshift, contrary to what some would have you believe.
With the shifter in OD or 3, if it will launch from 1st gear and shift up to 3rd, and command a 4th gear but not achieve it then most likely the problem is in the servo or as mentioned previously a stuck #8 checkball in the valve body seperator plate as mentioned previously.
The key is that it will indeed complete the 1/2 and 2/3 upshifts automatically.
If you would like to call me tomorrow I would not mind discussing it in detail so that you can understand whats happening and then work from a position of strength. I know you're in a bind and don't mind helping as best I can.
g
With the shifter in OD or 3, if it will launch from 1st gear and shift up to 3rd, and command a 4th gear but not achieve it then most likely the problem is in the servo or as mentioned previously a stuck #8 checkball in the valve body seperator plate as mentioned previously.
The key is that it will indeed complete the 1/2 and 2/3 upshifts automatically.
If you would like to call me tomorrow I would not mind discussing it in detail so that you can understand whats happening and then work from a position of strength. I know you're in a bind and don't mind helping as best I can.
g
09-28-2011, 04:24 AM
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Thanks Guys! Thanks for the input guys! (even the 'funny' answers- I CAN still run the 1/4...)
Sorry I was away for a while, life got too busy.
I took it to a friend's shop & we hooked up the SnapOn scanner & I drove it around for about 10 minutes. It was showing both the linkage being in OD and the 'call' to go into OD.
But, the trans just stayed in third, even when shifting up & down manually (from third to fourth).
The poor engine has 165K on it and I don't like taching it up all the time to drive it on the highway, but right now it's my daily driver...
I appreciate your offer Gilbert and will try to call today!
Sorry I was away for a while, life got too busy.
I took it to a friend's shop & we hooked up the SnapOn scanner & I drove it around for about 10 minutes. It was showing both the linkage being in OD and the 'call' to go into OD.
But, the trans just stayed in third, even when shifting up & down manually (from third to fourth).
The poor engine has 165K on it and I don't like taching it up all the time to drive it on the highway, but right now it's my daily driver...
I appreciate your offer Gilbert and will try to call today!
09-28-2011, 10:19 AM
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A lot of people don't tell the difference between OD-unlocked and
D. If you have a scan tool the real giveaway is the input / output
shaft RPM ratio, that one never lies. If it's 1:1 then you're in D
and if it's ~0.7 then OD. TCC Slip RPM is the other thing you want
to know for a fact (1:1 and no slip RPM is locked 3rd, 0.7:1 and
significant slip us unlocked 4th).
D. If you have a scan tool the real giveaway is the input / output
shaft RPM ratio, that one never lies. If it's 1:1 then you're in D
and if it's ~0.7 then OD. TCC Slip RPM is the other thing you want
to know for a fact (1:1 and no slip RPM is locked 3rd, 0.7:1 and
significant slip us unlocked 4th).
09-29-2011, 08:06 PM
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I'm having exactly the same problem with my 95z. I took it to my transmission man and he said the same thing Gilbert said. The computer is calling for OD but it stays in third. My 1,2,D are perfect. I'll let everyone know when we find out what happened.
10-10-2011, 10:46 AM
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I've done a little trouble shooting this weekend. I am stiil waiting on my transmission man to get an opening. Anyway I pulled out the servos and found the fourth apply piston was installed backwards. So I put all new o-rings on and put it back together, went for a drive and now I can fill a small shift into overdrive. The rpms only drop about 200. Do yall think running with the fourth apply pistion in backwards damaged anthing?
