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mike switzer
mike switzer,
Category: Transmissions
Satisfied Customers: 645
Experience:  lead diagnostic tech at Aamco
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I have a 4l60e transmission that won't shift out of 1rst

Customer Question

I have a 4l60e transmission that won't shift out of 1rst gear at wide open throttle, it shifts fine in all other gears. I have replaced the tps but it still does it. It's not giving me any codes & the check engine light is not on.
JA: Does the light stay on, or does it blink?
Customer: No light
JA: What is the model/year of your transmissions?
Customer: 1995 Chevy Silverado 1500 4x4 5.0
JA: Are you fixing your Silverado 1500 yourself? What have you tried so far?
Customer: Yes , all I have tried at this point is changing the tps .
JA: Anything else you want the mechanic to know before I connect you?
Customer: I ordered a new kit to replace the fluid , filter & the shift solenoid
Submitted: 10 months ago.
Category: Transmissions
Expert:  mike switzer replied 10 months ago.

when you said it shifts fine in all other gears what do you mean by this?

Customer: replied 10 months ago.
2nd to 3rd is smooth & 3rd to 4th is smooth
Expert:  mike switzer replied 10 months ago.

is this if you manually shift the transmission?

Expert:  mike switzer replied 10 months ago.

or if you ease into the throttle the transmission shifts?

Customer: replied 10 months ago.
It will shift from 1rst to 2nd smooth if I let off the gas a little. I havnt tried to manually shift it. I've just been letting off the gas a little to let it shift. If I stay on the throttle it wil shift, it just shifts hard.
Customer: replied 10 months ago.
It shifts fine after the 1rst to 2nd shift.
Expert:  mike switzer replied 10 months ago.

ok now i understand a little better. theses transmissions are also effected on the shifting from the maf sensor. have you tried cleaning the sensor. if not i would start with cleaning the sensor and see how it shifts from there. if you still have an issue try both manually shifting it while the transmission is plugged in. and then manually shifting with the transmission unplugged. with the transmission unplugged you will have harsh engagements and shifts as you will have max line pressure at this moment. if you dont have harsh engagements you have a bad transmission. these transmissions are known to have valve body issues with valves sticking and you will probably be able to get away with swapping the valve body out if that is the issue. also the shift solenoids are and EPC solenoids are known to stick and are fairly inexpensive and easy to change. if the maf sensor does no solve the issue and manually shifting it seems to operate normally. i would start with changing the solenoids and transmission harness in the pan. since they are not to expensive and if yout in there changing one its a mess to have to do it again to change another. make sure you get the epc solenoid that matches the one you have they had two different variations.

Customer: replied 10 months ago.
Can I get expert Tim to help me please
Customer: replied 10 months ago.
Epc solenoid??? Is that different than the shift solenoid???? How do I unplug the transmission??
Customer: replied 10 months ago.
This truck doesn't come with a maf sensor.
Customer: replied 10 months ago.
What's the name of the harness ,please??
Expert:  mike switzer replied 10 months ago.

sorry for the delay i have been having internet issues all day. i have not seen a chevy or gm vehicle that does not have a maf sensor.

the epc solenoid is the main solenoid that controls the internal line pressure in the transmission. to unplug the harness there is a heat shield on the passenger side of the transmission that will need to be removed it is held on with two 10mm bolts. after removing that the plug is above the pan near the back you squeeze both sides of the plug and lift up.

the epc solenoid is located directly under where the harness enters the transmission. as far as ording it i would label it the internal solenoid harness or valve body harness when looking it up.

Customer: replied 10 months ago.
Ok so the epc solenoid is inside the transmission???? I'll be able to just drop the pan & change the epc solenoid & the shift solenoids correct??? Also I don't know where the maf is located, my truck has a carborator with a regular air filter can you send me a picture or diagram as to where it's located & I'll try that first
Expert:  mike switzer replied 10 months ago.

has this engine been swapped not gm vehicle in 95 has a carb. maybe throttle body injected but ob2 or even obd1 vehicles are non carbed

Expert:  mike switzer replied 10 months ago.

yes the epc solenoid is inside the trans pan. you will be able to access all the solenoids with the pan and filter off.

Customer: replied 10 months ago.
its throttle body injected.... Obd1 can you help me locate that maf
Expert:  mike switzer replied 10 months ago.

since it is throttle body injected it does not have the maf. i apologize i was working with someone else on a newer silverado at the same time. same issue. have you cleaned the throttle body?

Customer: replied 10 months ago.
I havnt cleaned it . It has 150000 miles on it! What is best to clean it??? I can just spray cleaner on it correct???
Expert:  mike switzer replied 10 months ago.

yes thottle body cleaner works well. i would do it with the engine running

Customer: replied 10 months ago.
Ok I'll clean that & change the filter & the solenoids in the pan! Should I change the valve body while I'm in there???? I found an original gm one on line for 55$. Is that complicated???
Expert:  mike switzer replied 10 months ago.

its not too complicated. the main thing to pay attention to is the manual valve making sure you get that hooked back up correctly. that is the valve in the body and links up to the shift lever it just has a groove you have to line up no bolts or clips on that