I just did a BITOG-approved 'bucket flush' on the wife's '01 Chevy Lumina today. It's a method that I initially had reservations about (seeings how a transmission requires lube oil returning from the cooler circuit), but people on this site have convinced me that my concerns were unfounded (since only the parts turning at idle are the torque converter, input shaft, pump, and forward clutch hub).
I bought this car a few years back with 159,000 miles on it. This was from a fleet auction at the local college. Looked and drove like a new car... all highway miles, excellent maintenance (including records). Included in the laundry-list of maintenance & repairs that I did to the car before handing it over to the wife was a transmission filter change and refill with Dexron VI (latest and greatest... had just been released by GM). I also added a tranny cooler from an '04 Ford Expedition (ebay), my own custom-made filter base with a small-black Chevy oil filter (later upgraded to the Duramax filter, with a larger can and a built-in 10psi bypass), and welded provisions for a drain plug in the transmission pan. I've been replacing that in-line filter yearly.
I know that a flush wasn't really necessary 30k later, especially considering that DexVI is supposed to last forever (more or less). But this car has always had a soft 1-2 upshift at full throttle (flawless otherwise). From what I've read, this is a common problem with these vehicles... I don't THINK DexVI is the cause, but it's worth investigating. And I've recently come into a MASSIVE stash of Castrol Transynd ATF (fully synthetic Dex III, meets Allison's TES-295 spec). I also wanted to inspect the pan for debris to get an idea of how long I can reasonably extend the pan-drop interval with this setup.
Sorry, I didn't bother with pictures. But the pan was pretty much spotless. There was a thin film on the pan magnet- no other debris or crud besides that. I went ahead and replaced the filter since I already had one, and augmented the pan magnet with a hard-drive magnet that I recently salvaged (for those not nerdy enough to be familiar with hard-drive magnets, these are so strong that pliers are required if you want to remove one that's stuck to a flat piece of steel). I made sure it was stuck well away from any solenoids or wiring, just in case.
This tranny has a pan-drop capacity of about 7 quarts, and a total capacity of 10-12 quarts (depending on who you ask). With the pan back up, I dumped 14 quarts of Transynd into the transmission, ran a cooler line into a bucket, pumped out 7 quarts, and topped off.
Conclusions: There was so little crud in the pan (I'm assuming that the inline filter caught most of it) that I think I'll have no problem leaving the suction filter in place for 100k miles. I'll probably stick with 30k drain & fills and annual inline filter replacements from now on (still more maintenance than required, but I'm a bit obsessive about this sort of thing... and I mean to get AT LEAST 300k out of this car). I'll give this new fluid about 1000 miles to get good and soaked into the clutches, then check the 1-2 shift. I don't expect any noticeable difference... but might get lucky.
I bought this car a few years back with 159,000 miles on it. This was from a fleet auction at the local college. Looked and drove like a new car... all highway miles, excellent maintenance (including records). Included in the laundry-list of maintenance & repairs that I did to the car before handing it over to the wife was a transmission filter change and refill with Dexron VI (latest and greatest... had just been released by GM). I also added a tranny cooler from an '04 Ford Expedition (ebay), my own custom-made filter base with a small-black Chevy oil filter (later upgraded to the Duramax filter, with a larger can and a built-in 10psi bypass), and welded provisions for a drain plug in the transmission pan. I've been replacing that in-line filter yearly.
I know that a flush wasn't really necessary 30k later, especially considering that DexVI is supposed to last forever (more or less). But this car has always had a soft 1-2 upshift at full throttle (flawless otherwise). From what I've read, this is a common problem with these vehicles... I don't THINK DexVI is the cause, but it's worth investigating. And I've recently come into a MASSIVE stash of Castrol Transynd ATF (fully synthetic Dex III, meets Allison's TES-295 spec). I also wanted to inspect the pan for debris to get an idea of how long I can reasonably extend the pan-drop interval with this setup.
Sorry, I didn't bother with pictures. But the pan was pretty much spotless. There was a thin film on the pan magnet- no other debris or crud besides that. I went ahead and replaced the filter since I already had one, and augmented the pan magnet with a hard-drive magnet that I recently salvaged (for those not nerdy enough to be familiar with hard-drive magnets, these are so strong that pliers are required if you want to remove one that's stuck to a flat piece of steel). I made sure it was stuck well away from any solenoids or wiring, just in case.
This tranny has a pan-drop capacity of about 7 quarts, and a total capacity of 10-12 quarts (depending on who you ask). With the pan back up, I dumped 14 quarts of Transynd into the transmission, ran a cooler line into a bucket, pumped out 7 quarts, and topped off.
Conclusions: There was so little crud in the pan (I'm assuming that the inline filter caught most of it) that I think I'll have no problem leaving the suction filter in place for 100k miles. I'll probably stick with 30k drain & fills and annual inline filter replacements from now on (still more maintenance than required, but I'm a bit obsessive about this sort of thing... and I mean to get AT LEAST 300k out of this car). I'll give this new fluid about 1000 miles to get good and soaked into the clutches, then check the 1-2 shift. I don't expect any noticeable difference... but might get lucky.
