Shift Pointers
- Author: Wayne Colonna, Technical Editor
- Subject Matter: Installing transmission
- Issue: Avoid crushing filter and pan
Be careful with that jack
After a transmission is bolted to the engine in high ground clearance trucks, there are times that the jack does not have a high enough lift so as to install the cross member. One obvious solution to this problem would be to not raise the vehicle so high on the hoist in the first place. Another might be to carefully lower the hoist to give the jack the reach it needs. Another less desirable method would be to place a block of wood onto the saddle of the jack. If care is not taken, this can push the pan into the filter compromising its function and/or structure. An even greater risk is enclosing all four finger brackets on the saddle to be used to push up the transmission with these fingers directly on the bottom pan. The same devastating results may occur with the use of a jiggle jack. The success of some of these less desirable methods is determined in part by the strength of the pan.
One consequence of these practices can be damage to the pan, as with this dented pan, outside view (Figure 1) and inside (Figure 2).
The filter also faces ruination, as in Figure 3, showing that the standoffs on the filter and at the base of the standoffs are cracked open due to the pan crushing the filter.
There is a transmission that has a pan that cannot stand up to much of any pressure if applied to it unevenly. The pan will immediately push into the filter. The filter is designed with standoffs that sit up against the valve body. This keeps the filter down into the pan. When the pan is pushed in, it compresses the filter causing the standoffs to break the top side of the filter quickly. The filter will then suck air causing the pump to cavitate resulting in noise, unstable line pressure and definite transmission failure.
The transmission we are talking about is the 6L80 family of transmissions. It’s quite surprising to know the many times we have encountered this installation error. It is essential that the entire pan be fully supported by a saddle to distribute the pressure evenly across the bottom of the transmission. This will prevent damage to both the pan and filter resulting in immediate failure of your rebuilt transmission.
