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Hey guys, first off, I have searched and read many posts on this topic and know there are mixed opinions on this topic but I have to ask anyway. I just picked up a used 02 Tahoe with 155,000k miles. The prior owner said that he would occasionally pump 4 quarts of fluid out of the fill tube and replace it with new fluid but he never dropped the pan and changed the filter. The original owner may have but it is really unknown if it has ever been done. Now that i have it, I am going through it and wanting to do all the maintenance. Also, what about changing the differential fluid?? Is it needed or just leave it alone. I really would appreciate feedback from you guys on this one.

Also....what type of fluid do you recommend for the transmission and rear???

Thanks.

Rich
 

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Are you asking if you should change the tranny fluid by doing a pan drop? I would say yes. I dont know what typed of fluid I would use cause I have not done it to my truck but there are other threads they mention what a good type of fluid would work.
 

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The Treasure State
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Alright here we go, take notes now.

Transmission takes about 16qts if you actually want to flush it, however with that many miles on it often times a complete flush results in the new detergents attacking all the gunk buildup that has deposited itself in various corners of the tranny. This causes it to all break loose at once, plug up the filter and generally kills the tranny within a few 100 miles.

My recomendation, pick up ~4-6qts of Dex VI(6) rated fluid, and a tranny filter from GM. Drain then drop the pan, swap out the filter and refill w/ the DexVI. Remember to fill to the full line with it off, start the truck and check with it running. My personal preference is to get the fluid level as close as I can with it cold then bring it up to operating temp and make sure the fluid fits within the HOT area on the stick. Then from here on out just drain and top off your tranny fluid when you do an oil change. This way you slowly introduce fresh fluid and prevent "shocking" the transmission.

As for the rearend. 75-90W. (2qt) Your 02 should have a drain plug on the bottom of the diff to drain the rearend with. However with as many miles as you have you should pull the cover to wipe off the magnet. Clean everything up, mainly get all the gasket material off. I have take an old shirt, stuffed it in the rearend to cover up the ring gear and all the open area and useed a wire brush cup on a grinder to get all the material off and give it a spotless surface. Clean up with some de-greaser to get it all clean. Soak up the extra lube that always wants to drip out so you are not putting a gasket on an oily surface. Finally when putting it back on, spend the extra $10 and get a gasket from GM. It will seal faster and easier than RTV.

The front end is 80-90W (2qt)and if you can't change that fluid w/o help then you need help. My only pointer is for you to go out and buy a suction gun. Looks like a grease gun body w/ a plastic hose on the end. Suck up the gear lube, squirt it in the diff. Worth every penny of the $15 it cost at NAPA.

Lastly, while you are down there, replace the fluid in your T-Case. Assuming it is an Auto-Trac (has the AUTO button on the dash), you MUST use the GM fluid. DO NOT USE ANYTHING BUT Autotrac-II fluid. It is bright blue and costs about $8 a qt at the dealer. You need 2qts. Once again, suction gun is a huge help.

Tools needed, various meteric socket sizes, suction gun, 3/8" allen wrench or 3/8" allen wrench head socket.
 

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I don't have a truck
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I'd install a drain plug on the tranny while you've got the pan off.

Good info though :shake:
 

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The Treasure State
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I'd install a drain plug on the tranny while you've got the pan off.

Good info though :shake:
He said its an 02. I believe that 99-02 GM put drain plugs in the tranny pan and the rearend. They got cheap in 03 and pulled all that stuff out to save a dime. :crazy: But I have known to be wrong before. Either way, if it doesn't have a drain plug, put one in. Hell if it doesn't have a plug and it were my rig I would just drill the pan while it was on the truck to drain the fluid out, then put the new plug in when I had the pan off. Getting splashed with a few gallons of ATF while trying to get the pan to fit around the crossmember, exhaust and shifter bracket while its full of fluid is never fun. Even with the drain plug there is still a good qt that is left that splashes everywhere.

Oh, when your filling it up. Once it is full go out and take it for a drive, run it through the gears then check the fluid level again. There are lots of little spots that fluid can hide in the tranny.
 

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He said its an 02. I believe that 99-02 GM put drain plugs in the tranny pan and the rearend. They got cheap in 03 and pulled all that stuff out to save a dime.
There is one, but I know very few people who have actually gotten theirs off. Both of mine on both my 4l60e transmissions I have owned were seized on there.
 

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I don't have a truck
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My uncles 99 didnt have one :hmm:

Yeah, the older trucks got stuff like that and I guess it's nice.

What happened to my NNBS with an underhood light, footwell lights, trans plug, rear end plug, and stuff like that?
 

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Discussion Starter #9
Thanks for the great advice. Mine is a 2WD so I don't have to worry about the front end or transfer fluid. The prior owner said that he did try to drain the pan once but couldn't get the drain plug out. Is this a common problem?? Is there a good way to go about getting it out?? Vise grips and pull like hell?? Let me know. Thanks again.

Rich
 
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