4L60E Shift pattern is 1-2-1-2

[SubXero0]

Hi, Im new to these forums since I recently got a 96 Silverado with the 4l60e in it on the road after sitting for 5 years, and it shifts like 1-2-1-2. My dads saying its transmission filter, other than him Ive had no other input. Im curious if I should just throw this transmission out or attempt to get it to shift into 3rd and 4th or if its completely junked. Thank you.

 

[JPVortex]

Hi, Im new to these forums since I recently got a 96 Silverado with the 4l60e in it on the road after sitting for 5 years, and it shifts like 1-2-1-2. My dads saying its transmission filter, other than him Ive had no other input. Im curious if I should just throw this transmission out or attempt to get it to shift into 3rd and 4th or if its completely junked. Thank you.

Trans is probably junk. Most common failure for no 3rd and 4th/overdrive is worn out 3-4 clutch pack, only real fix is a full rebuild.

 

[NickTransmissions]

Hi, Im new to these forums since I recently got a 96 Silverado with the 4l60e in it on the road after sitting for 5 years, and it shifts like 1-2-1-2. My dads saying its transmission filter, other than him Ive had no other input. Im curious if I should just throw this transmission out or attempt to get it to shift into 3rd and 4th or if its completely junked. Thank you.

Is it hanging in 2nd gear or upshifting into 3rd but feels like it's in neutral?

If the former, connect a bi directional scan tool, take it for a test drive and watch the live transmission data to see what's going on...

If the latter see post#2 above and my 4L60E Information thread for rebuild information.

 

[Schurkey]

96 Silverado with the 4l60e

it shifts like 1-2-1-2.

From a stop, it has first gear. You gather some speed, it shifts to second. You go faster still, it drops back to first gear with the engine revved way up, and then ends up in second gear again?

Any '96 with goofy transmission problems, needs to have the computer checked for the updated wiring per the GM bulletin. This is the second guy with a failed transmission that I've suggested the wiring bulletin update, but I don't have a link to that info. It's on this forum...somewhere.

 

[SubXero0]

From a stop, it has first gear. You gather some speed, it shifts to second. You go faster still, it drops back to first gear with the engine revved way up, and then ends up in second gear again?

Any '96 with goofy transmission problems, needs to have the computer checked for the updated wiring per the GM bulletin. This is the second guy with a failed transmission that I've suggested the wiring bulletin update, but I don't have a link to that info. It's on this forum...somewhere.

Yeah that perfectly describes it. Ill look around for that bulletin. Thank you

 

[Schurkey]

If the trans kicks-down from second to first, I'd be looking at the TPS and MAP to assure that the computer isn't deliberately "kicking down" a gear 'cause it thinks the throttle has been whacked open.

Yeah, this could be some sort of transmission internal failure, or maybe an electrical-control failure...but let's rule out engine issues first. Connect a scan tool, verify EVERY sensor and computer output...but especially TPS and MAP.

 

[SubXero0]

If the trans kicks-down from second to first, I'd be looking at the TPS and MAP to assure that the computer isn't deliberately "kicking down" a gear 'cause it thinks the throttle has been whacked open.

Yeah, this could be some sort of transmission internal failure, or maybe an electrical-control failure...but let's rule out engine issues first. Connect a scan tool, verify EVERY sensor and computer output...but especially TPS and MAP.

Ive checked the sensors and know theyre good. only code its throwing is p0308 and occasionally p0420. The misfire codes from I assume the cam I put in it because the bottom end I have is from a TBI motor and didnt change the cam out when swapping everything. Ill try that bulletin when I can.

 

[NickTransmissions]

Ive checked the sensors and know theyre good. only code its throwing is p0308 and occasionally p0420. The misfire codes from I assume the cam I put in it because the bottom end I have is from a TBI motor and didnt change the cam out when swapping everything. Ill try that bulletin when I can.

So the transmission never tries to upshift into third gear regardless of road speed?

 

[SubXero0]

So the transmission never tries to upshift into third gear regardless of road speed?

It seems to try around 25-30 mph but feels like 1st and it only accelerates at 3-4k rpm travelling at that speed. Then letting it attempt to shift to 4th it shifts to what feels like 2nd. If I manually select 2nd after it goes to "4th" it feels like it does downshift.

 

[NickTransmissions]

It seems to try around 25-30 mph but feels like 1st and it only accelerates at 3-4k rpm travelling at that speed. Then letting it attempt to shift to 4th it shifts to what feels like 2nd. If I manually select 2nd after it goes to "4th" it feels like it does downshift.

You really need to stick a scan tool on there to see what the transmission is doing before going any further but it seems like your 3-4 pack is burnt.

When the band is applied you will have either 2nd or 4th. The only difference is whether the 3-4 pack is also applied and holding. If the 3-4 pack and band are applied along with the forward clutch you have fourth gear. If the 3-4 pack isnt holding but band is applied, you will have second gear. So if your scan tool shows that the pcm is commanding a shift into third from second but you're not mechanically shifting into third then that 3-4 pack is wiped and trans has to come out.

95% of all 4L60Es come in for overhaul due to the loss/burn up of the 3-4 clutch pack.