4l60E rebuild issues
Thread Starter
Teching In
Joined: Jan 2020
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4l60E rebuild issues Hello, I'm new to the forum but have been reading them for years! I recently did a complete rebuild on a 4l60e. All new seals, clutches, electronics, and a transgo hd2 shift kit. The trans shifts through all of the gears but it has low line pressure. The line pressure is at 75 at idle and stays at 75 on acceleration. If I unplug the trans connector the line pressure does increase to 230ish, the needle bounces a little. I replaced the pcs solenoid just to eliminate that. If I command the PCM to decrease the amperage on the force motor to .1 amp the line pressure only increases to 100. I checked the PCS wires from the PCM to the trans and it shows continuity. I'm not sure what to try next! Thank in advanced!!
TECH Junkie
Joined: Jun 2008
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From: Nitro Alley
At 0.100A a stock unit should have between 165.00 - 185.00 Psi.
I Have seen a bad park/ neutral switch cause what you are experiencing, as well as a bad PCM.
Do you have any DTCs?
On rare occasions I have also seen a separator plate/ gasket mix match cause similar conditions.
Make sure the PCM can see the gear selector potions correctly first.
I Have seen a bad park/ neutral switch cause what you are experiencing, as well as a bad PCM.
Do you have any DTCs?
On rare occasions I have also seen a separator plate/ gasket mix match cause similar conditions.
Make sure the PCM can see the gear selector potions correctly first.
Thread Starter
Teching In
Joined: Jan 2020
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There are no DTCs. It is a swap vehicle so no p/n switch on the trans. The correct separator plate with gaskets are installed. I will try another PCM this weekend. Can the PCM fail and just effect PCS solenoid?
TECH Junkie
Joined: Jun 2008
Posts: 3,204
Likes: 1,391
From: Nitro Alley
The PCM needs to receive information from the park neutral switch for the transmission to operate properly.
Did you jumper both sides of the neutral safety circuit together so that the engine will start???
If the PCM sees the manual valve position, incorrectly in neutral... the PCM will not command the pressure control solenoid to allow line pressure to rise the same as if in gear.
Please explain how you have the PCM/ transmission management installed and configured.
Did you jumper both sides of the neutral safety circuit together so that the engine will start???
If the PCM sees the manual valve position, incorrectly in neutral... the PCM will not command the pressure control solenoid to allow line pressure to rise the same as if in gear.
Please explain how you have the PCM/ transmission management installed and configured.
Last edited by vorteciroc; Jan 8, 2020 at 07:36 PM.
The PCM needs the PSM signal. It doesn't need the neutral safety switch to alter line pressure. (yes the neutral safety switches other things such as idle timing, etc)
I'm guessing the neutral safety wires were jumped to get the engine to run.
I'm guessing the neutral safety wires were jumped to get the engine to run.
Thread Starter
Teching In
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So I have the neutral safety switch on the column but it’s not tied into the PCM. I just changed the PNRDL to none in hp tuners and it seems to have fixed it. I will drive it more tomorrow and report back. Thank you for your help I would have chased that around for weeks!
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