65 GS 4-speed trans on Ebay

[Brian]

Transmisson for a '65 GS on Ebay:

item # 160594287349

Has the correct tail housing, correct gear set (see the 3 rings around the input shaft), and has the correct 27 spline output shaft.   Side cover has been changed to the older, stronger sand cast style. 

[Mister T]

Link -> http://cgi.ebay.com/ebaymotors/_W0QQcmdZViewItemQQ_rdcZ1QQitemZ160594287349QQruZhttpQ3aQ2fQ2fshopQ2eebayQ2ecomQ3a80Q2fiQ2ehtmlQ3fQ5ffromQ3dR40Q26Q5ftrksidQ3dp5197Q2em570Q2el1313Q26Q5fnkwQ3d160594287349Q26Q5fsacatQ3dSeeQ2dAllQ2dCategoriesQ26Q5ffviQ3d1

[WkillGS]

Auction description says it's date coded 63-64. Tailshaft should have a date code on it too.
Anybody know when the 'GS' coded tailshafts first appeared? Ted said he has those on some of his Wildcats.... I'd guess '65 was the first appearance, but that's just a guess..
Brian, did some '65's have aluminum side covers?

[Brian]

Every 64 and 65 Buick Skylark 4-speed trans I have ever seen had an aluminum side cover on it.  I have never seen a cast iron side cover.  All the ones I have ever seen in Buicks had the die-cast aluminum side cover, and they are prone to cracking on both ends of the center rib because of the factory shifter not having stops in it.  That is why alot of the T10s I have come across have had the side cover swapped out with one of the sand cast ones from and early 60's T10 (like the one on Ebay now).  They fit and function the same and are alot stronger--they just look different.  The one I am putting in John Crouse's car now had a cracked side cover and I put one of the older sand cast ones on it. 
  The tail housing in my GS has a 64 date code on it--my car was built in Jan of 65, so that is the date you would expect to see on a car built then. 
  Also note that the main case on the one on Ebay is probably not the original.  The 64 and 65 T10 cases had the casting numbers down low toward the front near the drain plug, and the older ones had it up high, centered on the side of the case.  Functionally identical, just a visibile indication you can use to date the main case. 

[WkillGS]

Thanks for the info Brian.
My 65 GS is a very late build, August 1965.
It has a cast-iron side cover, as do my '66 trannies.
My '65 cover is dated F24 = June 24, 1965
Mark has a cover dated 4th week of Feb 1965 that is alum (according to to info in Duane's date-code-book)
The tailshaft is dated 3-24-65. I believe the trans build date is July, 1965, but I'd have to confirm that.
It looks like Buick made a change from an aluminum side cover to a cast iron cover sometime during the 1965 model year.
Maybe that depends on the assembly plant? My '65 is a Baltimore build.

[Brian]

Here is probably why they went to the cast iron side cover.  The factory style shifter does not have stops built into the mechanism like a Hurst does, so the side cover takes the force when you keep pushing on the stick once it is already in a gear.  If you find one of the covers pictured that is on a 64 or early 65 small block Skylark with the factory Hurst shifter, they are always perfect with no cracks.  The one in this pic came off of a late 65 skylark with a 300 engine and the GM shifter.