4L60E / 1-2 Shifting when Hot
Thread Starter
Teching In
Joined: Sep 2004
Posts: 3
Likes: 0
From: Venezuela
4L60E / 1-2 Shifting when Hot Blazer 4 x 2 / 1998 / When Cold all Ok. One of the two problems ( not both ) appears when Hot:
1) When shifting from 1st -> 2nd jumps, OR,
2) When selecting Reverse or Drive / OD from Park or Neutral you can feel it engages. Then when accelerates to run it jumps. Is like a second engaging but stronger. In this case the 1 -> 2 shifting is Ok...
The shifting from 2 -> Drive -> OverDrive never have problems.
While reducing speed nothing wear is noted.
It happen too that when selecting 2nd being stopped, it starts in 2nd and not in 1st.
Interesting, Isnīt it ?
1) When shifting from 1st -> 2nd jumps, OR,
2) When selecting Reverse or Drive / OD from Park or Neutral you can feel it engages. Then when accelerates to run it jumps. Is like a second engaging but stronger. In this case the 1 -> 2 shifting is Ok...
The shifting from 2 -> Drive -> OverDrive never have problems.
While reducing speed nothing wear is noted.
It happen too that when selecting 2nd being stopped, it starts in 2nd and not in 1st.
Interesting, Isnīt it ?
Originally Posted by Rmartin2004
Blazer 4 x 2 / 1998 / When Cold all Ok. One of the two problems ( not both ) appears when Hot:
1) When shifting from 1st -> 2nd jumps, OR,
2) When selecting Reverse or Drive / OD from Park or Neutral you can feel it engages. Then when accelerates to run it jumps. Is like a second engaging but stronger. In this case the 1 -> 2 shifting is Ok...
The shifting from 2 -> Drive -> OverDrive never have problems.
While reducing speed nothing wear is noted.
It happen too that when selecting 2nd being stopped, it starts in 2nd and not in 1st.
Interesting, Isnīt it ?
1) When shifting from 1st -> 2nd jumps, OR,
2) When selecting Reverse or Drive / OD from Park or Neutral you can feel it engages. Then when accelerates to run it jumps. Is like a second engaging but stronger. In this case the 1 -> 2 shifting is Ok...
The shifting from 2 -> Drive -> OverDrive never have problems.
While reducing speed nothing wear is noted.
It happen too that when selecting 2nd being stopped, it starts in 2nd and not in 1st.
Interesting, Isnīt it ?
Thread Starter
Teching In
Joined: Sep 2004
Posts: 3
Likes: 0
From: Venezuela
Valve Pressure Control ?
Originally Posted by Gen3Benz
Id start by looking up bulletins. I think 96-98 had some valvebody bulletins for the trucks.
One guy with some experience told me that similar problems have been soved replacing the Valve, Pressure Control, GMC Part No. 24220158. Could it be possible ? . Where can I find the possible bulletin / tech notes for the valvebody of those trucks ?...
Thanks in advance...
Best place to look up bulletins is the dealership, or gm tech site online.
Maybe you could ask a service advisor or a tech at a dealership.
I have replaced entire valvebodie's because of the bulletin. wish i had specific details on that bulletin.
Pressure control solenoids have caused a lot of garage shift problems and some shifting problems(mostly 1-2). could be electrical or mechanical. i have ****-canned a bunch of PC solenoids in FWD GM transmissions 97-99 for
these symptoms.
Found some
87-71-74 NOV 98 A/T - 1-2 Accumulator Piston/Outer Spring Replacement
01-07-30-012 APR 01 A/T - 4L60 E Revised Valve Body/Spacer/Gaskets
01-07-30-023B MAR 02 A/T - 4L60-E Harsh 1-2 Gear Upshift/MIL/SES/CEL ON
Maybe you could ask a service advisor or a tech at a dealership.
I have replaced entire valvebodie's because of the bulletin. wish i had specific details on that bulletin.
Pressure control solenoids have caused a lot of garage shift problems and some shifting problems(mostly 1-2). could be electrical or mechanical. i have ****-canned a bunch of PC solenoids in FWD GM transmissions 97-99 for
these symptoms.
Found some
87-71-74 NOV 98 A/T - 1-2 Accumulator Piston/Outer Spring Replacement
01-07-30-012 APR 01 A/T - 4L60 E Revised Valve Body/Spacer/Gaskets
01-07-30-023B MAR 02 A/T - 4L60-E Harsh 1-2 Gear Upshift/MIL/SES/CEL ON
Last edited by Gen3Benz; Sep 15, 2004 at 12:34 AM.
The description of the problem and how you can recreate it leaves me a little confused, but consider this:
Could the "jump" you are describing also be described as a "clunk?"
GM has notorious problem with slipyoke sticking causing a condition that feels like a transmission or suspension jolt, bump, or clunk.
Also, putting the selector into "2" from a stop will make it take off in second. This is an intentional feature for slippery conditions.
Could the "jump" you are describing also be described as a "clunk?"
GM has notorious problem with slipyoke sticking causing a condition that feels like a transmission or suspension jolt, bump, or clunk.
Also, putting the selector into "2" from a stop will make it take off in second. This is an intentional feature for slippery conditions.
