You are buying a tool that is used to expand the sealing rings on either a 4L80E or a 4L85E transmission.

We invented this little tool, we call it the “mushroom”.  If you see another listing for a similar part – BEWARE it’s an off shore copy!  Our part is often copied, never duplicated!

The tool combines both of the GM Kent-Moore tools, we have gone through several of the plastic ones last year so we decided to make them out of aluminum and have not had to replace it as of yet.  It is very simple to use:

  • Lubricate the expander
  • Simply slide the desired seal over the tool
  • Leave the seal on the tool for a minimum of 30 seconds
  • Remove the seal from the tool
  • Since the tool has the same OD as the factory plastic tool, you will have to slightly work the seal into the groove(s)
  • Install the inner most seal first
  • Center the new seals in the groove
  • Lubricate the seal sizer with trans-gel
  • Gently guide the tool sizer over the seal to collapse it into the groove and size it.

We also have the seal sizers available and will combine shipping on multiple orders.