I had some time off from work today, so I decided to change the transmission fluid and filter in my 2003 Trailblazer that currently has about 130K miles on it. It is a 4L60E transmission and began experiencing a hard 1-2 shift at about 114K miles. The fluid was previously changed by the dealer at about 30K and 70K miles but this is the first time that the pan has ever been off for a filter change. I added Lubeguard Red at about 119K miles and it has helped, but not cured, the shift issue. It is intermittent now, sometimes it shifts the way that it used to before the issue developed but most of the time it shifts firmly; although not as hard as it did before the addition of Lubguard Red.
I dropped the pan and was surprised at how clean it was. What I could see of the filter material also didn't look bad. The fluid still had some red color to it and didn't smell burnt, but was considerably darker than new fluid. I removed the 1-2 accumulator for inspection to see if it wasn't the cause of the overly firm 1-2 shift. It appeared fine to my eye. There were no cracks in the piston or springs and the piston seal was in good shape. I wasn't brave enough to remove the valve body for inspection.
I installed the new filter, replaced the pan, and filled it with Valvoline Dex VI with a bottle of Lubguard Red. I disconnected a line to the transmission cooler and started the engine to pump out the remaining old fluid in the torque converter.
I haven't had a chance to take it out for a good test drive yet to see if there is any noticeable difference in shift quality.
Cheers,
Jeff
I dropped the pan and was surprised at how clean it was. What I could see of the filter material also didn't look bad. The fluid still had some red color to it and didn't smell burnt, but was considerably darker than new fluid. I removed the 1-2 accumulator for inspection to see if it wasn't the cause of the overly firm 1-2 shift. It appeared fine to my eye. There were no cracks in the piston or springs and the piston seal was in good shape. I wasn't brave enough to remove the valve body for inspection.
I installed the new filter, replaced the pan, and filled it with Valvoline Dex VI with a bottle of Lubguard Red. I disconnected a line to the transmission cooler and started the engine to pump out the remaining old fluid in the torque converter.
I haven't had a chance to take it out for a good test drive yet to see if there is any noticeable difference in shift quality.
Cheers,
Jeff