Tranny Fluid & Filter change

[Meathead16]

I know this is often asked, and that there is no for sure answer one way or the other, but I wanted to get some opinions on my case specifically to try and decide how to proceed

I need a transmission rebuild, but scheduling and financial reasons have forced my hand at delaying the job for the time being. I understand the risk involved in that it may leave me stranded on the side of the road one of these days, especially since symptoms have been presenting themselves for about 2 years now. There is 236k miles on the truck, and I have no reason to believe it's not the original transmission. I did a fluid and filter change when I purchased the truck 2 years ago at about 210k miles. One thing to note is that when trying to remove the pan I was having some issues and was banging into the solenoids a few times, more or less. There was a lot of stuff on the magnet in the pan and the pan in general was full of grit. No chunks or pieces, just a bunch of that slurry that forms on the magnet. From what I remember, fluid was dark, but did not smell burnt.

I am thinking of doing another fluid and filter change. I have new solenoids I wanted to put in as well. My thinking is that with all the junk that has probably begun to accumulate, one or more solenoids might be contaminated making things worse. My symptoms are 2-3 shift flare, bangs into reverse, harsh 1-2 shift (only when cold), and general slipping. By general slipping I mean that which gears slip and when seems a bit random. Sometimes it only slips between 1 or 1 gears, sometimes it slips between all of them, sometimes only upshifting, sometimes only downshifting. It might decide to only do it when it's cold or cold it might be fine and just does it after its warmed up and I've been driving all day. No real rhyme or reason to it. Half the time it works just fine, no slipping at all. I have noticed that when it is slipping pretty consistantly on a drive, turning haul/tow mode on seems to get it back on track. Truck in general feels sluggish as well. My avalanche with the 5.3 had more pep in it than this truck does, though if I floor it she goes. With light throttle movement feels strained, like when you make your kid do something they don't want to do and they take forever moping over there to do it.

My concern is that I may have reached the point where the clutch material floating around in the transmission is what's keeping it going and that if I replace it with fresh fluid it'll completely die on me as I've seen mentioned on here and many other places warning not to change the fluid (especially not a flush) with higher mileage or symptoms. Seeing as it's only a pan drop, only 5qts(?) will get swapped, I'm thinking what's left of the old will mix in and give it that friction it needs? (If that's really how that works). I remember @NickTransmissions saying at some point that a fresh filter and pan drop fluid change is always a good thing. Does this apply in all situations or is there a limit? Am I probably ok since I did a pan drop 25k ago? Or should I just let it be and start seriously planning for my drive to LV?

Thanks in advance

 

[justirv]

I know this is often asked, and that there is no for sure answer one way or the other, but I wanted to get some opinions on my case specifically to try and decide how to proceed

I need a transmission rebuild, but scheduling and financial reasons have forced my hand at delaying the job for the time being. I understand the risk involved in that it may leave me stranded on the side of the road one of these days, especially since symptoms have been presenting themselves for about 2 years now. There is 236k miles on the truck, and I have no reason to believe it's not the original transmission. I did a fluid and filter change when I purchased the truck 2 years ago at about 210k miles. One thing to note is that when trying to remove the pan I was having some issues and was banging into the solenoids a few times, more or less. There was a lot of stuff on the magnet in the pan and the pan in general was full of grit. No chunks or pieces, just a bunch of that slurry that forms on the magnet. From what I remember, fluid was dark, but did not smell burnt.

I am thinking of doing another fluid and filter change. I have new solenoids I wanted to put in as well. My thinking is that with all the junk that has probably begun to accumulate, one or more solenoids might be contaminated making things worse. My symptoms are 2-3 shift flare, bangs into reverse, harsh 1-2 shift (only when cold), and general slipping. By general slipping I mean that which gears slip and when seems a bit random. Sometimes it only slips between 1 or 1 gears, sometimes it slips between all of them, sometimes only upshifting, sometimes only downshifting. It might decide to only do it when it's cold or cold it might be fine and just does it after its warmed up and I've been driving all day. No real rhyme or reason to it. Half the time it works just fine, no slipping at all. I have noticed that when it is slipping pretty consistantly on a drive, turning haul/tow mode on seems to get it back on track. Truck in general feels sluggish as well. My avalanche with the 5.3 had more pep in it than this truck does, though if I floor it she goes. With light throttle movement feels strained, like when you make your kid do something they don't want to do and they take forever moping over there to do it.

My concern is that I may have reached the point where the clutch material floating around in the transmission is what's keeping it going and that if I replace it with fresh fluid it'll completely die on me as I've seen mentioned on here and many other places warning not to change the fluid (especially not a flush) with higher mileage or symptoms. Seeing as it's only a pan drop, only 5qts(?) will get swapped, I'm thinking what's left of the old will mix in and give it that friction it needs? (If that's really how that works). I remember @NickTransmissions saying at some point that a fresh filter and pan drop fluid change is always a good thing. Does this apply in all situations or is there a limit? Am I probably ok since I did a pan drop 25k ago? Or should I just let it be and start seriously planning for my drive to LV?

Thanks in advance

I'm not sure about putting in new parts outside of fluid and filter at this point. I would plan on a rebuild. I would caution on any long trips, and be weary of those that might include strong grades or inclines.

 

[jfoj]

Assume you had been checking trans fluid levels on a regular basis??

My 2005 Yukon Denali AWD had a problem with the transfer case seal that let the trans leak fluid into the transfer case. No fluid on the ground, but finally figure out the transfer case was overfilling because fluid from the trans would work its way to the transfer case. The AWD transfer case used ATF anyway.

So I could go 1-2 qts low on fluid without an external leak. Usually a few qts low would cause the TCC to drop in and out, never had flares, harsh shifts or banging into gear.

Worth checking the level again to make sure trans is not low.

Good luck.