Any potential downsides to doing this?

 

Miss Daisy might be startled when you put it in Reverse.
Seriously, these transmissions were designed to minimize the driver feeling shifts, TCC engagement and anything else. That is why we need to modify them for performance use.

 

So true. It's been 12 years since I did my first converter and HD-2 and I had forgotten how agonizingly slow the stock reverse engagement was. And of how much I hated the stock transmission operation in general. But I do remember that I drove it off the lot with the intention of modifying it from the get-go.

 

If the reverse input clutches come before the low/reverse clutches apply, then you will have a harsh reverse engagement. You want the low/reverse clutches applying first. Removing the checkball will speed up the apply of the low/reverse clutches. This should make the reverse engagement smoother. If the reverse input clutches come on first, then the removal of the checkball can make for a noticeable reverse engagement. I always leave out this checkball without a problem when I build the unit or in all of my rebuild kits.