Question about GMC Sierra 1500

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I have a 1990 GMC sierra. The transmission is starting to slip a bit. I just bought the truck from a one owner. It has 85,000 miles on it. I need to change the transmission filter and flush and replace the fluid. I want to do it by myself and not pay the shop. Some people are saying you can flush the tank with mineral spirits. I am not sure abou this. What is the smartest, most effective, and safest way for me to flush my fluid and change my filter. I am assuming that: 1) I will remove the plug and let the fluid drain all the way out. 2) I will clean the plug and put it back in. 3) I wll pull out the filter and replace with a new one. 4) I will refill the fluid reservoir. But if I do all these things, I still haven't flushed ALL of the old fluid. I also want to improve gas mileage. I have been reading online about adding a small amount of pure acetane to the tank. Does this work? is this smart? What are some engine improvements I can make to get better gas mileage?

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Don't listen to people , you do not want to add anything like acetone or mineral spirits. Will eat Neoprene parts . Your best bet take an have the transmission serviced by a qualified repair shop .

Posted on Mar 08, 2017


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Posted on Jan 02, 2017

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SOURCE: 99 GMC K 1500 Transmission burning fluid and comeing out blow-by

The fluid boiling over is caused by the slippage heating up the fluid, your clutch pack is worn out, you will need an overhaul.

Posted on Nov 07, 2008

  • 962 Answers

SOURCE: gas mileage drop

It is not the fuel pump if you hear it when you turn the key. you will hear a whirring noise. that's the fuel pump.A fuel pump will usually go out suddenly. Could be you need spark plugs if you replaced the wires. Always be sure to properly gap the spark plugs with a small guage you can buy for a couple dollars or could add fuel injector cleaner to your tank just to make sure. The fuel filter (need only one) run from $30-36 dollars. the air filters cost about $16-17 dollars. go to Amazon .com to get an idea of the prices. he reason the needle on the fuel gauage goes down is that with a 1/4 tank the gas inside the tank moves and the electric guage float moves as you turn.With more gas you will not see that too often.Is it a 2 wheel drive or 4 wheel drive ? The 4 wheel drives use more gas. You can go to toyotanation dot com to find any thing toyota related.Clean the IAC Valve (idle control valve) just inside where you remove the duct work from the air filter.Spray it with brake cleaner or carburator cleaner towards the fuel system. With the engine running at about 1200 rpms.Do this several times, you can see the valve inside. It can also be removed and cleaned. they get full of gunk and oil residue.I don't think the 97 has cabin air filters.Only the air is not as bad as you think. Hope this helps you out.

Posted on Dec 27, 2008

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SOURCE: Exploded transmission 48 hours after ATF flush

I see no correlation between the two events.  Things just happen on an old car.  I'd question spending money to fix the 11-year old car, or replace it with something newer and less miles.  I'd replace the car.  

Posted on Mar 25, 2009

  • 103 Answers

SOURCE: Transmission fluid flushing

In normal situations people do not flush their trannys. Your would normally just lower the pand and change the filter and replace the fluid that came out. If you are not having a problem with your tranny this is what I would suggest. As the fluid gets older the tranny gets "used to" the old oil that is in there. When you add new fluids the new fluid contains detergents that clean the internal parts as they circulate. Unless this is the first time you've been to the recommended mileage for changing the fluid (I.E. 30,000 miles) you could flush it. If you do not know the history of changes, or if you are at, lets say 100,000 miles I wouldn't recommend flushing it. When the new detergents clean out the parts they remove gunk that is actually helping the transmission. Don't get me wrong, you don't want a whole lot of gunk, but you also don't want to remove gunk that for example is holding a pin in place, so the pin falls out (just an example) I hope this wasn't too hard to understand, and I hope I answered your question.

Posted on May 18, 2009

  • 45 Answers

SOURCE: I bought a 2006 GMC Sierra 3500 Duramax

Hi: the 06 Duramax came with a LBZ, 18 mpg is normal, to improve it ... "chip" it, put in an "AirRaid air filter and a 5 inch exhaust. (cost about $1,000.00) Fuel mileage improved by over 30%.

Posted on May 22, 2009

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