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MemphisMan

4T60E Shifting Issue: 95 Cutlass Supreme

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A week after returning from the June W-Body meet, my transmission started shifting erratically between 2nd and 3rd gears.  From a dead stop, it would shift out of 1st normally, stay in 2nd for a split second, then shift to 3rd, causing my engine RPMs to go down until I got up to speed.  When I got my speed up, it would shift fine between 3rd and 4th.  I checked the fluid level and it was just under that "add" line.  I replaced the filter and fluid and it seemed to resolve the issue...until yesterday when it started doing the same thing.  The car has 85,7xx miles and the transmission has never been serviced.  Any ideas?

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I assume you checked the fluid again? Do you have tuner pro to check the temps and see the gear commands?

Yes, I checked the fluid, and unfortunately, it's full to the top mark.  I don't have tuner pro either :-/

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Does anyone local to you have a tech2 or other tool to help see what might be going on?  

 

When is the last time it was serviced?  Is anything else strange going on with the car?

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Nothing else going on with the car. I changed the transmission fluid and filter about 400 miles ago. It was doing the same thing before I changed the fluid, but stopped immediately after the change. Now, 400 miles later, it’s doing the same thing.

 

 

Sent from my iPhone using Tapatalk

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From what I can gather, the issue is it's just not staying in 2nd long enough and shifting to 3rd way too soon? That's an interesting one. I agree with the tech 2/scanner route. Gear selection is fully electronic. The PCM commands shift solenoids on the e version. I agree and think you have to start out by watching with a scanner and see what the PCM is commanding to determine if something is causing the PCM to select 3rd when it shouldn't, or if it's not selecting 3rd and something in the trans is effed. Also make sure your early shift is not the TCC. The 4T60e usually locks the TCC before it's in 4th gear. I can't remember if it's during 2nd or 3rd gear. I want to say it's third though.

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On 7/21/2018 at 9:59 PM, jman093 said:

From what I can gather, the issue is it's just not staying in 2nd long enough and shifting to 3rd way too soon? That's an interesting one. I agree with the tech 2/scanner route. Gear selection is fully electronic. The PCM commands shift solenoids on the e version. I agree and think you have to start out by watching with a scanner and see what the PCM is commanding to determine if something is causing the PCM to select 3rd when it shouldn't, or if it's not selecting 3rd and something in the trans is effed. Also make sure your early shift is not the TCC. The 4T60e usually locks the TCC before it's in 4th gear. I can't remember if it's during 2nd or 3rd gear. I want to say it's third though.

Yeah, seems like it's not staying in 2nd for very long.  Looks like I gotta get smart on tech 2.  It's weird not driving it.  At least I got the AC working in the coupe and have been enjoying driving it.  More to follow when I start troubleshooting.  Thanks for all of the replies.

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On 7/21/2018 at 10:59 PM, jman093 said:

 Also make sure your early shift is not the TCC. The 4T60e usually locks the TCC before it's in 4th gear. I can't remember if it's during 2nd or 3rd gear. I want to say it's third though.

Can't speak for an OBDII environment but in an OBDI its lock up after 4th.

 

11 hours ago, MemphisMan said:

Yeah, seems like it's not staying in 2nd for very long.  Looks like I gotta get smart on tech 2.  It's weird not driving it.  At least I got the AC working in the coupe and have been enjoying driving it.  More to follow when I start troubleshooting.  Thanks for all of the replies.

How the the trans behave when you shift manually or place the shifter in 3rd locking out 4th or 2nd locking out 3rd?

 

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On 7/26/2018 at 8:47 AM, 55trucker said:

Can't speak for an OBDII environment but in an OBDI its lock up after 4th.

 

The converter will lock in 3rd even on OBD1 cars(4T60-E) around 40mph at light throttle cruising. If you have tunerpro, you can look at the parameters necessary for lockup to occur in either 3rd or 4th.

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