I would just like to say thanks to all the regular posters, without your knowledge and willingness to help us amateurs, it would have taken me forever to rebuild my trans and most likely have it explode. I have spent more than 12mths reading through many threads (most more than once)and haven't needed to ask many questions as I could normally find the answers already posted.

Finished my 1st 4l60e rebuild, stock except for Z-pack, 5 pinion rear planet, corvette servo ( trans have factory vett servo anyway, and yes I know, I bought parts before I knew better) kept it simple for 1st build. I will do much more on next 4l60e, I have 3 broken ones that I have bought to practice on as I have 2 cars ( one with 450rwhp so far )with ls1 engines and 4l60e transmissions, I also have a heavy foot and a lot of tires.

So got trans in the car and had no 2nd gear, would shift 1st to 3rd had 4, R and converter lockup, again read through others threads and worked through to finally end up adding a blob of weld (0.100 longer after reshaping ) to lengthen servo pin. Last straw move as nothing else worked.

Question is: why did I need to lengthen pin as drum was in really good condition, and band was new (bought on ebay), servo has pin with 2 groves on end so thats the longest pin of the 3 pins you can get right, and is this going to cause me any problems later on. ( apart from now having a longer pin)

Again, thanks so much for being willing to share your time and wisdom to help us newbies keep our junk running. This is my GM-H 1973 HQ Holden Statesman, was factory 350 SBC and turbo 350 trans, 10 bolt diff.

 

Should you plan to do anything like this again; it would be wise to invest in an ATSG manual for the model transmission you are working on.

To answer your question; a 2-4 servo apply pin with no grooves, is the longest OEM pin as per the chart above.

Sonnax also offers a longer pin; which is my particular favorite. Sonnax part #77787-02K shown below.



The sonnax part comes with two white seals... Should you ever purchase this part, do not use the seals.
I personally hate those white split seals.



You should instead use the red solid teflon rings intended to be a governor seal in the THM200-4R.

Purchase two of them and you are good to go.

Shown below.

 

Also If have helped you, or passed on any information that has made this easier for you... You are welcome.