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GMC Forum: 95 GMC Sierra 1500 Truck automatic transmission problems?
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  #1  
Old 06-14-2010, 01:23 PM
David W David W is offline
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Default 95 GMC Sierra 1500 Truck automatic transmission problems?

It starts when you go to turn it on, the dash lights will not come on (part of the time) when this happens, the RPM gauge and speedometer will no work and the Check Gauges light is on. When this happens the transmission will not have first gear, only second and above and reverse, plus the power is diminished. I believe the problem is in the electric components and not the actual transmission. If I were to play with the wheel adjustments the dash/gauges will start working and the transmission works fine and sometimes they will kick on while going down the road, and only once to my knowledge, they have gone off. If any of you out there any explanations I would like to hear them. Thank You.
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Old 06-14-2010, 01:32 PM
Molson02536 Molson02536 is offline
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Quote:
Originally Posted by David W View Post
It starts when you go to turn it on, the dash lights will not come on (part of the time) when this happens, the RPM gauge and speedometer will no work and the Check Gauges light is on. When this happens the transmission will not have first gear, only second and above and reverse, plus the power is diminished. I believe the problem is in the electric components and not the actual transmission. If I were to play with the wheel adjustments the dash/gauges will start working and the transmission works fine and sometimes they will kick on while going down the road, and only once to my knowledge, they have gone off. If any of you out there any explanations I would like to hear them. Thank You.
Your transmission is in limp mode due to a faulty ignition switch.

What is "limp-home mode" ? This is a fault mode in which the transmission either loses electrical power or the PCM deactivates all of the electronics. The transmission will default to max line pressure. The driver will have Reverse and 3rd, with manual 2nd available by putting the gearshift in 2 or 1 (doesn't matter). 1st, 4th, and TCC lockup will not be available. It will not hurt the car to drive it like this for short periods, but use manual 2nd to get the car moving, and be aware that the trans will generate more heat than normal while operating in limp-home mode due to increased torque converter slippage during 2nd gear starts and no lockup in 3rd gear.

This is a pretty common problem to confirm the cause. The simple test is to check for ignition voltage at the "Trans" fuse, #20, 10 amp at the fuse box. No power here with the key on and most likely the ignition switch is faulty.

This fuse is powered by a white wire from the ignition switch. Check there for power as well, with the key on. If power is not present, the only other test is for power on the red wire at terminal D5 of the ignition switch connector. It is easier to just confirm power on both red wires and not worry about terminal designations.

Start with that and post me back.
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Old 01-25-2012, 02:20 PM
dunkley90t dunkley90t is offline
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Default trannie problems

i have a 95 gmc ext cab with the trannie has no reverse i was wantin to know if a 96 chevy with ext cab trans will work thay both are 4l60 ? thanks for any info .
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Old 01-25-2012, 11:22 PM
Molson02536 Molson02536 is offline
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i have a 95 gmc ext cab with the trannie has no reverse i was wantin to know if a 96 chevy with ext cab trans will work thay both are 4l60 ? thanks for any info .
Best is to check which 4L60E you have in your 95. The 1995 4L60E was an odd ball year and if your lucky, you may have the 4L60E transmission in there now.

The 2 transmissions use a different 3-2 solenoid that ohm different. If you swap them, you'll throw it into fail safe and throw a 3-2 solenoid code.

I've seen "budget" shops attempt to swap the solenoid and harness only. The problem is, the 3-2 down valve, itself, is different. Swapping just the solenoid/harness will create a 3-2 runaway problem on a forced downshift.

BTW, the tail housings and speedometers are different, too.

Good luck and keep us posted.
Molson02536
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Old 02-01-2012, 06:24 AM
dunkley90t dunkley90t is offline
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Default

thank u for info just gona part it out instead if fix...
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Old 02-04-2012, 10:16 PM
plains123 plains123 is offline
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Quote:
Originally Posted by David W View Post
It starts when you go to turn it on, the dash lights will not come on (part of the time) when this happens, the RPM gauge and speedometer will no work and the Check Gauges light is on. When this happens the transmission will not have first gear, only second and above and reverse, plus the power is diminished. I believe the problem is in the electric components and not the actual transmission. If I were to play with the wheel adjustments the dash/gauges will start working and the transmission works fine and sometimes they will kick on while going down the road, and only once to my knowledge, they have gone off. If any of you out there any explanations I would like to hear them. Thank You.
Did you ever found the problem with your transmission? Was it the ignition switch? I got the same problem,please reply friend,

Pat
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