1996 GMC S15 Transmission Problems

Tiny
MIKEGMC
  • MEMBER
  • 1996 GMC S15
  • 6 CYL
  • 4WD
  • AUTOMATIC
  • 165,000 MILES
Hello,
I am having trouble with my GMC. I drive the vehicle for about 5 min and the transmission slips. I shut the vehicle off and turn it back on. Two to three min later the same thing happens again. I was wondering if the solenoid is on its way out or could it be something else?


Thank you,

Mike V.
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Monday, February 2nd, 2009 AT 5:45 PM

9 Replies

Tiny
BLUELIGHTNIN6
  • EXPERT
Hello
Thanks for the donation.

The first step to do is to check your fluids. How long since last replacing the tranny fluid and filter? If it has been awhile then you should do that and see if it helps. If it doesn't help then it will have to be inspected. Could be solenoids worn out, may also be torque converter issue.

Let me know how that tranny fluid looks and if the new fluid helps, I will follow up.

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Tuesday, February 3rd, 2009 AT 12:41 AM
Tiny
MIKEGMC
  • MEMBER
I should have said that the tranny just cuts out. The fluid is clean. It does not smell burned. It has been a while since I had the filter changed. If it is the filter then why does it come back only after a few min after starting it back up. I turn the vehicle off then right back on again. It's fine for a few min.
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Tuesday, February 3rd, 2009 AT 7:14 AM
Tiny
BLUELIGHTNIN6
  • EXPERT
The filter itself wouldn't be the issue. Mainly the fluid would be the only reason as far as fluid and filter go. I just stated filter as well because you get filter changed with fluid. If fluid is clean then next step of diagnosis is to inspect transmission related linkages, vacuum hoses, and electrical connections that may be loose or disconnected. One of the most common problems are corroded battery terminal connections, so don't overlook that. If all looks OK here as well, you will need to have a reputable tranny shop run a diagnostic on the elec. Components. Since late model transmissions are controlled by a computer that operates shift and pressure control solenoids inside the transmission, the computer needs to be electrically scanned by a transmission professional to determine if any electronic control problems exist.

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Tuesday, February 3rd, 2009 AT 8:05 AM
Tiny
MIKEGMC
  • MEMBER
I have checked for loose conections, battery is fine, I had the tranny scanned and everything seems to be fine. Is there anything else I should look for?
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Friday, February 6th, 2009 AT 10:24 AM
Tiny
BLUELIGHTNIN6
  • EXPERT
Any other signs occuring while driving? Clunking, jerking when shifting out of Park?

Inspect the U-joints for wear. If OK here, you can check the resistance of shift solenoids. Use an ohmeter to check Ohms. Should not be higher than 4.5 Ohms. If it is, replace solenoid.

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Friday, February 6th, 2009 AT 11:32 AM
Tiny
MIKEGMC
  • MEMBER
I changed the tranny filter and fluid. The fluid was clean. In the bottom of the pan was a fair amount of sludge and the magnet had a lot of filings on it. I gave the pan and magnet a good cleaning. I changed everything out and put it back together. I took my gmc for a short ride. Then I took a 1/2 hour drive. I could not believe that it was running great again. Thank you for your knowledge. I have a question. When should I change everything again? 10,000 20,000 or more miles?

Thanks again,

Mike V.
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Thursday, February 12th, 2009 AT 9:39 PM
Tiny
BLUELIGHTNIN6
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Every 30,000 miles to change tranny fluid and filter under severe driving conditions (sandy roads, trailer hauling. Etc.) Or 70,000 miles under normal conditions.

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Friday, February 13th, 2009 AT 12:05 AM
Tiny
MIKEGMC
  • MEMBER
Hello,

I drove about 100 miles and it's back again. I do not know why my filter keeps getting clogged? This time a flatbed picked my truck up. He said that this particular truck can't be towed by a regular tow truck. I've been towing my GMC behind my RV each summer. This is the first time I've heard I couldn't tow it. Is the flatbed driver right? Did I do damage without knowing it? I'm stumped as to what to do next. I hope you can still help me.

Mike
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Thursday, February 19th, 2009 AT 12:59 AM
Tiny
BLUELIGHTNIN6
  • EXPERT
Some vehicles can't be towed on their wheels but your vehicle should be fine to tow? Below are the towing instructions for Chevy/GMC trucks.

2-WHEEL DRIVE

Chevrolet and GMC Pick-ups can be towed on all four wheels (flat towed) at speeds of less than 35 mph (56 kph), for distances less than 50 miles (80 kph), providing that the axle, driveline and engine/transmission are normally operable. The transmission should be in Neutral, the engine off, the steering unlocked, and the parking brake released.

The rear wheels must be raised off the ground or the driveshaft disconnected when the transmission if not operating properly, or when speeds of over 35 mph (56 kph) will be used or when towing more than 50 miles. (80 kph).

Do not attach chains to the bumpers or bracketing. All attachments must be made to the structural members. Safety chains should be used. It should also be remembered that power steering and brake assists will not be working with the engine off.

4-WHEEL DRIVE

Remember that the power steering and power brakes will not have their power assist with the engine off. The only safe way to tow is with a tow bar. The steering column must be unlocked and the parking brake released. Attachments should be made to the frame and to the bumper or its brackets. Safety chains are also required.

If your having issues again then it really sounds more like an internal problem and the new fluid/filter just delayed the issue some. I would suggest having the tranny diagnosed at a reputable repair shop to save it. There are a lot of internal components that can cause it to slip and there is no way to pinpoint the exact component without a diagnostic test run on it, sorry.

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Friday, February 20th, 2009 AT 1:07 AM

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