Preparing the Transmission for the Adapter Plate

Today I continued working on cleaning the 20 years of encrusted dirt and oil on the transmission housing.  It was very convenient to remove the two shift mechanisms prior to starting the cleaning process.  To complete the cleaning required 2 cans of Gunk Cleaner Gel applied in four applications.  Between each application the aluminum was scrubbed with a plastic brush and toothbrush as required, followed by power washing and finally air drying with compressed air prior to the application of the next “treatment”.  Since I have a chemistry background, other agents were tried after the Gunk cleanings.  Brasso, and in a separate trial, a 45% Potassium hydroxide solution in water were tried to see if the metal surface could be improved.  The Brasso had a very mild effect as demonstrated by the blackened shop rag that resulted.  The 45% Potassium hydroxide solution did not seem to have any effect, but when the housing was rinsed, the water rinse was a dark gray and cloudy, so something was happening after all.  Sadly, the surface of the housing was not improved enough to warrant additional effort with either of these agents.   Four hours was probably too much time to have spent on this, but the result was very pleasing to behold.

In the bottom picture the two bolts at about 12:00 and 1:00 normally secure the starter.  Except for the two bolts at the top left (in the square portion of the housing), all of the housing bolts fall in a perfect circle.   The unit weighed in at 29.0 kg (63.87 pounds).  My next task will be to remove the flywheel from the engine and make the measurements needed for the machine shop to fabricate the adapter plate and shaft hub.

Looking at the bottom picture, the OEM bolts that originally held the transmission to the engine, were located at  

12:00        Torx M12-50 mm 

12:30        Torx M10-65  (starter bolt)

01:30        M8

02:00        Torx M10-65 (starter bolt)

02:45        Dowell 14.5mm (10.69 mm length), Torx M12-90 mm

03:30        Torx  M8-50

05:30        Torx   M8-50

07:00        Torx   M8-50

07:30        Dowell 14.5mm (10.69 mm length), Torx M12-90 mm

09:00        6 mm hex bolt ?

10:00        Torx M12-50 mm

Total OEM bolt count is 3 x M8-50, 2 x M12-50, 2 x M12-90, and 2 x M10-65.