Thanks Charlie. As for Dratts... I think this car is going to be a fair-weather baby... and we have clean roads in Nova Scotia (well... until harvest time that is.) Bubbajoe, that is a great idea. I'll post an updated photo when I get around to doing just what you said.

And now… for the transmission. Most people reading this thread are well aware of the incredible deals that were to be had starting about a year ago on Pontiac G6 transmissions, but for those tuning in for the first time, here’s a brief summary. In 2006, Pontiac offered a new higher-powered version of the G6 sport sedan called the GTP. The GTP had a 240 horsepower 3.9 L V6 with variable valve timing which came standard with a four-speed automatic transmission, but for no cost, a six-speed manual transmission was available. The transmissions fabricated by GME in Germany are known as the F40 (RPO code MT2) and came with the following gear ratios: 3.77 / 2.04 / 1.32 / 0.95 / 0.76 / 0.62 / Rev 3.54 with an axle ratio of 3.55 which gave a final drive raito (in top gear) of 2.51:1. The torque capacity was officially rated at 295 lbft.



These transmissions however were superseded in 2007 with ones having slightly different ratios and a few improvements to counter noise complaints, resulting in a surplus of F40’s. Sometime in 2008 these surplus transmissions started appearing for retail sale through a number of online sites for approximately $400 - $500, an incredible deal considering they were brand new, and worth between $4000 - $5000 in 2007. I bought mine from a company in Michigan called Schram Auto Parts for a grand total of $666 including shipping, duties and taxes.



The nice thing about the F40 and the Cadillac Northstar, as many people know, is that they have nearly compatible bellhousing patterns. The major differences are the starter locations, a slight interference with the Northstar’s rear mounted coolant manifold, and one bolt hole that doesn’t line up with the rest. The F40 and the Northstar have been mated successfully by several people here on PFF and the next couple posts will really only be duplicating what has already been done before. The difference is that I hope to provide a bit more detail on how to go about doing the necessary mods.

So then, the first thing that needed to be done was to sit down with a ruler, a compass, and some cardboard to make a template of the F40’s bellhousing flange. With a mock-up traced out, and using the top two mounting holes, I then transferred the template to the rear of the Northstar. That’s when I first noticed the interference with the water log and carefully trimmed out the triangular piece to the left of the picture. Then I measured the location of the starter snout on the engine in relation to the top two bolt holes and traced it onto the template so I could transfer the starter location back to the F40.



Here are the critical dimensions for anyone doing this in the future. Basically locate the center of starter hole 58mm to the right of the top left bolt as viewed from the bellhousing side of the transmission. Then, drop 55mm down at 90* from the top edge of the bellhousing to locate the center of the starter. Use that point to draw a 70mm diameter circle (35mm radius), which is just large enough to clear the diameter of the starter snout.



Use an exacto knife or something similar to cut out the hole since you’ll need to keep the circle for later. Next, test fit the template on the engine to be sure the starter hole is properly located. Once satisfied I had the hole in the right place (if you look carefully, it took me two tries!), I relocated the template back on the transmission using the two top bolts, and colored the edges of the webs that I could see through the starter hole using a red marker. Notice that the hole isn’t centered on the vertical web of the transmission.



Then, to locate the depth of the starter notch on the horizontal web, I took the 70mm round hole I cut out earlier, drew a line through the center of it, and used it to trace a half circle under the horizontal web, lining it up on the red marks I had made earlier. Finally, to get the right depth of the notch on the vertical web, I just measured 35mm from the machined edge back along the intersection of the two webs and then eyeballed the quarter round shape using that mark and the one made earlier on the vertical web using the template. If you can’t follow what I just wrote, then this picture should help:



The next step was what I thought would be the easy part: cuting out the notch. Ha! That aluminium is hard! I first started with a fluted grinding bit on my die grinder and it worked OK for the first bit but then galled up with semi-molten aluminium.



Next, I tried what I call a Zippy-tool… it’s basically a dremel on steroids that uses special bits that look sort of like drill bits, except they’re made to be used like a router. That thing made the going a little easier, but it still took me close to 1.5 hours to do it right, and not have it looking like some butcher with a sawzall did it. The most difficult part was the vertical web since there isn’t a lot of room to manouvre.



Here are the parts (finally) out of the way:



And here I am test fitting the 70mm circle to be certain I cut enough material away both horizontally and vertically.




Lastly, here is the nicely finished notch once I was satisfied the profile was right and after I cleaned the edges with a 2” sanding drum.

[This message has been edited by Bloozberry (edited 11-11-2010).]