Transmission Shifting Problems?

1995 CHEVROLET SUBURBAN
107,891 MILES • V8 • 4WD • AUTOMATIC
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VENOM20056
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I have a 95 chevy k2500 4x4 (w/ OBD 1) and the transmission doesn't shift. I have changed the input and output sensors located on the tranny and transfer case thinking that it would solve the problem. Shifted fine for a few days but the problem is still occurring. The check engine light is not on and everything else is working the way that is should. What else would cause my tranny not to be shifting?
Jan 21, 2011 at 5:34 AM
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DOCFIXIT
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Think shift solenoid "A" #13 in diagram it not opening either faulty , O ring or clogged up. need to pull pan down and remove and test to see if it opens when voltage is applied.

These guides will help us

https://www.2carpros.com/articles/how-to-service-an-automatic-transmission

and

https://www.2carpros.com/articles/automatic-transmission-problems

Check out the diagrams (Below). Please let us know what you find.

Jan 21, 2011 at 6:59 PM
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OSCAR442CUTLASS
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Hello, why would my transmission shift like its a manual. all the gears work except i have to let off the gas so it will shift i already droppd the pan and checked all the solenoids and they are good and the filter seems in good shape it was serviced about 6 months ago. i am really frustrated. im thnking it has to do with the valve body but im not sure can someone help?
Sep 15, 2020 at 10:25 AM (Merged)
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DOCFIXIT
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See if there are any codes present see diagram jumper between A & B, key on MIL will flash. So flash, flash pause flash is 21. post codes
Can you manually up shift without letting off gass? Does it down shift ?
Sep 15, 2020 at 10:25 AM (Merged)
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CHITOWNKILLJOY
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My transmission will not shift into 2nd or 3rd gear we changed the filter but it still won't shift
Sep 15, 2020 at 10:25 AM (Merged)
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HMAC300
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scan for codes but it kind of sounds like either a governor problem or valve body problem so a trans guy will have to look at it.
Sep 15, 2020 at 10:25 AM (Merged)
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CHITOWNKILLJOY
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Thanks I'm Going To Get It Checked Out
Sep 15, 2020 at 10:25 AM (Merged)
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MLINDSAY
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My suburban just came out of the shop - they installed a starter and fuel pump w/fuel filter.

1st day car drove great, no shifting problems.

2nd day car won't shift out of 1st gear.

The suburban hasn't been driven in approx. 3 months and was just sitting in the garage until I could get enough money to pay for the repairs.

Thanks in advance for any help.

Mark
Sep 15, 2020 at 10:26 AM (Merged)
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DOCFIXIT
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Hello,

This sounds like you have a shift solenoid for 2nd gear that is not working. Here is a guide to help you get the pan off

https://www.2carpros.com/articles/how-to-service-an-automatic-transmission

Here are diagrams to help you see what you are in for when doing the job

Here is a wiring diagram so you can tell which one is which.

Check out the diagrams (Below)

Please let us know what you find.

Cheers
Sep 15, 2020 at 10:26 AM (Merged)
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MLINDSAY
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Docfixit,

Yes, the transmission fluid is full, but, has a slight burned smell to it. When the suburban gets up to 30 mph, it doesn't shift and I loose drive power.

I stop, begin to apply gas and same thing happens at 30 mph.

No lights on the dash and the rpm's on the engine appear to be ok.

Would a transmission fluid change and filter help? I have owned the suburban for 7 years and have never changed the fluid. Also, the suburban wasn't driven from Sept. 08 to now.
Sep 15, 2020 at 10:26 AM (Merged)
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DOCFIXIT
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If fluid smells burnt sign of clutch slipping. A fluid and filter would not hurt and give you a chance to see if metal in pan.
Sep 15, 2020 at 10:26 AM (Merged)
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MLINDSAY
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Docfixit,

Thanks for the input/advice. I replaced the second gear solenoid and it works great.

Thanks!

Mark
Sep 15, 2020 at 10:26 AM (Merged)
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DOCFIXIT
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Good to hear, please use 2CarPros anytime we are here to help.

Cheers
Sep 15, 2020 at 10:26 AM (Merged)
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GNLSMAMA
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Brown and dark blue wire on a Delphi ECM #16147060? Truck not shifting w/o those wires. Transmission was transplanted from a donor and for some reason they are not there. Help!
Sep 15, 2020 at 10:26 AM (Merged)
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ASEMASTER6371
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truck will shift without those wires. the governor regulates the shifting in this trans.

did you take the sensor from your trans and install it on the donor?? are they the same trans???

Roy
Sep 15, 2020 at 10:26 AM (Merged)
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GNLSMAMA
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I believe it needs the vehicle speed buffer to reference vehicle speed. Swapped in a 4L80e transmission and the harness. Tranny goes into limp mode.
Sep 15, 2020 at 10:26 AM (Merged)
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ASEMASTER6371
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what was in it before??

Roy
Sep 15, 2020 at 10:26 AM (Merged)
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SSJAKE
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My SUV has the v10 bodystyle not the engine, it has a 350 Vortec with tbi, and it goes in and out of reverse and first great goes in and out of 4x4, but it will not shift from first to second.
Sep 15, 2020 at 10:26 AM (Merged)
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HMAC300
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scan for codes to see if you have any cross A and B on aldl then check fluid if dark brown or black transmission probably needs an overhaul. then see a transmission professional.
Sep 15, 2020 at 10:26 AM (Merged)
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SRV
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Hi Guys. Got an automatic 1994 Suburban 1500 with 300,000kms on a 350 with throttle body injection. It's always dropped a gear and handled the hills when we step on it but this fall after a summer of pulling the boat, it's bogging up hill and won't always drop a gear. It has a 2 year old aftermarket fuel pump and filter, new plugs, rotor and cap and a fresh air filter. Any ideas? thanks much
Sep 15, 2020 at 10:26 AM (Merged)
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WAYNO
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not sure if that year has a kickdown cable or not but if it does i would check that out, or maybe the valve body is possible having some issues.
Sep 15, 2020 at 10:26 AM (Merged)
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SRV
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[quote:d373da000a="wayno"]not sure if that year has a kickdown cable or not but if it does i would check that out, or maybe the valve body is possible having some issues.[/quote:d373da000a]
Thanks wayno.
I was thinking it might be the catalytic converter blocking the pipe so i took it to the muffler shop and sure enough the cat was rattling around plus the muffler was rusting through so we had the exhaust system replaced including O2 sensor, this made a big difference. It's pretty good now but i figure i may as well clean the valve body too. My buddy Phil the mechanic once said that it's often 2 things that are wrong since folks don't do enough preventative maintenance. Thanks for the thoughts, much appreciated :D
Sep 15, 2020 at 10:26 AM (Merged)