Thanks
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.







