Time for a tranny service
mishalah
03-10-2013, 03:31 PM
2004 Denali XL with 78,800 miles. I've had it since July '12, and when I changed the oil immediately after buying it (74,700 miles) it was low and filthy. All the fluids were checked/topped, and I had to rebuild the front drive diff and replace a cracked axle tube shortly thereafter. Everything has been fine since, except for some coolant spewing out mysteriously every once in a while......AND slightly more than a qt. of ATF just disappearing about a week or two ago.
It was shifting a little jerky so I checked the fluid and found it just barely on the stick. Quite a surprise since I check it every month or so (only 4000 miles since July), and I've never seen a drop on the ground. Anyway, since I have no idea if the last owner ever changed it or the filter I figure I'll get it done.
The big question is: flush?.....or do the standard filter and partial change? The fluid is pink and clean looking at this time. I see opinions about flushing all over the map here and other places....so what do tranny experts really say? What does the GM dealer say? What does the tranny maker say?
It was shifting a little jerky so I checked the fluid and found it just barely on the stick. Quite a surprise since I check it every month or so (only 4000 miles since July), and I've never seen a drop on the ground. Anyway, since I have no idea if the last owner ever changed it or the filter I figure I'll get it done.
The big question is: flush?.....or do the standard filter and partial change? The fluid is pink and clean looking at this time. I see opinions about flushing all over the map here and other places....so what do tranny experts really say? What does the GM dealer say? What does the tranny maker say?
maxwedge
03-10-2013, 04:58 PM
GM does not recommend the use of a flushing machine, also use Dexron VI, more expensive but it is superior to Dex111.
mishalah
03-10-2013, 05:29 PM
GM does not recommend the use of a flushing machine, also use Dexron VI, more expensive but it is superior to Dex111.
I did a full fluid and filter change (pumped it out through the tranny cooler lines)at 92,000 miles in my '05 Suburban -- from Dex III to Dex VI. It's a lot of work because all the Dex III has to come out. Coincidentally or not, I started having shifting issues not too long after (all at about 100,000 miles). I replaced several selenoids, the TCC harness, and finally the $1350 ECU before it got straightend out. I don't know what exactly caused the whole problem, but it was a nightmare. I'm gonna leave the Dex III in this one until I know for sure there won't be any future consequences....even though the Dex VI is MUCH better fluid.
These trannies are waaaaay to sensitive for this day and age.
I did a full fluid and filter change (pumped it out through the tranny cooler lines)at 92,000 miles in my '05 Suburban -- from Dex III to Dex VI. It's a lot of work because all the Dex III has to come out. Coincidentally or not, I started having shifting issues not too long after (all at about 100,000 miles). I replaced several selenoids, the TCC harness, and finally the $1350 ECU before it got straightend out. I don't know what exactly caused the whole problem, but it was a nightmare. I'm gonna leave the Dex III in this one until I know for sure there won't be any future consequences....even though the Dex VI is MUCH better fluid.
These trannies are waaaaay to sensitive for this day and age.
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