There has always been a need for perfect pump alignment, on most if not all units, there are exceptions. Many, require a special tool to align the body to the stator support, or the gears to the stator support to prevent bushing wear, noise, and front seal leaks.
There are many different tools to align pumps, each manufacturer, has their own, including the 6L80/90. The recommended tool is a ring to align both halves (Figure 1). Many tool suppliers have their own tool, each a little different, but the goal is to make it right!
Installing the pump cover/stator support onto the bellhousing using the tool is fairly simple. Install the pump cover/stator support to the bellhousing. Install the alignment tool onto the pump assembly. Install the pump cover/stator support bellhousing bolts and torque to 97 in. lbs.
But there is another way, let’s take a look at the pump cover/stator support a little closer. Notice there are 2 bolt holes that are smaller in diameter (Figure 2). These are located at the 5 and 11 o’clock positions, ever wonder why? I believe, GM uses these holes to align the two pump halves, by using 2 special aligning bolts. The same bolts that are used to align the Saturn TAAT valve body to the case. The alignment holes on the pump are located at 5 and 11 o’clock positions.
When you install these two aligning bolts they will fit snug, that’s ok, install all of the remaining bolts and torque them to 97 in. lbs. using a clockwise sequence (Figure 3). Once that’s done, remove the two aligning bolts as needed to complete the sequence, and install the two remaining pump cover/stator support bolts, #5 and #11 and torque to 97 in. lbs.
There are 4 aligning dowel bolts for the TAAT valve body to case, two of the bolts are long and two of the bolts are short, either pair works perfectly (Figure 4).
If you don’t have a TAAT unit laying around, you can make your own bolts, or have a machinist make you a set.
We have used this procedure for about 6 years now, on thousands of 6L80/90E pumps, and never had an issue with bushing wear or seal failure. Just another way to get the job done if you don’t have the alignment tool.
Special Thanks to Steven Spence, Newnan Ga, who identified this procedure, and provided the pictures.