Transmission problem?

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bottomline2000

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Sometimes it's worse to flush a dirty transmission. Your friction material is in the fluid once it gets dirty so when u flush it it has less to grab. Not the case with a well maintained transmission. Also, not replacing the filter can cause low pressure and increase the chances for slip and create heat which you now have the recipe for killing a trans..not sure the shop gave u good advice.

Also, Dex 6 is backwards compatible, dex 3 is not. When in doubt, go dex 6.

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sonic_the_hedgeh

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No check engine lights. So I am changing all fluids in the drive train. I had advice from quite a few friends with mechanical knowledge and one said could be the differential. So I am changing the transmission fluid, transfer case fluid is actually dextron 3 as well, and changing the front and rear differential fluid to see if that helps. If it doesn't eliminate the problem I am sure it will prevent a costly repair bill.

Checked service records and none indicate the diff and transfer case fluids were ever changed. (Except maybe at the dealership when it was a few years old). Anyways I hope it helps.

Plus replacing the fuel filter since it did have error codes in the past stating 2 banks in the engine were lean.

I will post after with results.

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Good news. My yukon does shift better but still slips or sticks. It really does seem like it sticks. It delays the shift then shifts. Oh well seems fine though

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sonic_the_hedgeh

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Oh yeah. I am changing the fluids today.
The transmission filter kit was cheaper than I thought. Thankfully it has a rubber gasket.
All my fluids are synthetic for the drivetrain.
Hopefully the shifting is a little smoother after this. Thanks for the information.

Plus you did clarify what I thought was true. This 4wd system cannot be disengaged.
Still have to check with a dealer and a few mechanics as to why a Yukon would be built with a spot for the fuse? Besides the Vin code actually mentions it has 4 wheel steering so possibly that is wrong as well. Possibly a mistake made by the manufacturer? Oh well. Someday I will figure that one out. Until then fluid time! Going to be great to get the drivetrain fluids changed.


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Thanks again chubbs for the information. Yes the trans just sticks...delays the shift. It doesn't shift rough though. I just let off on the gas pedal a bit and it shifts.

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sonic_the_hedgeh

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Makes me wonder if you have a MAF or TPS that's reading funky
The maf was dirty I did clean it but it acts up now and again. Just that a new one is very expensive. Thanks might have to try cleaning it again.

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sonic_the_hedgeh

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Graph your live data, go from there

TPS, RPM and MAF volume
Funny. I noticed a sticker pointing to where my pcv valvle is. No. Replaceable unit. I recall these from the old days and had to replace them. So while I was cleaning my intake I used about 25 percent of my can of seafoam and shot it into the pcv line and crankcase. Now my check engine light went out. Plus my shifting is so much smoother. Although I still think that tps needs replacing. Thanks for putting me on the correct path!

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sonic_the_hedgeh

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So I have used intake cleaner a few times by the throttle position. Sensor and then my check engine light goes off for a few hours to a few days. Getting that changed this week. Then a cooling system flush. I did use dextron 6 for the transmission. Thanks guys for all the input. Going to be great getting it fixed. Then in a month or so new tires at last.

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sonic_the_hedgeh

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Finally found out the transmission just needs new valves replaced on the bottom. It's a transgo kit I found on amazon. The valves synchronize the transmission!

Just drop the oil pan they are right there!

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wjburken

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Finally found out the transmission just needs new valves replaced on the bottom. It's a transgo kit I found on amazon. The valves synchronize the transmission!

Just drop the oil pan they are right there!

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Man...Hope that fixes this for you. Looks like you’ve been battling this for a long time so getting it taken care of finally has to be a relief. Way to stick with it.
 

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