I recently changed the gear oil in my 71 beetle. The new oil is 75w90 semi synthetic gear oil, and meets gl5 and mt-1 specs. Now whenever I try to downshift into 2nd or 1st gears, the gears grind. I can put in the clutch and go into 3rd or 4th no problem, but if I'm going into 1st or second it grinds. It upshifts fine, and will shift fine if I'm at a crawl, but I can't go down into 2nd until I'm below 10mph. All I've done is replace the gear oil, I swear I didn't mess with anything else. Is it possible the new oil is causing this problem? The new stuff seems a lot thicker than what came out of the tranny.
Thanks in advance, Mike
PS - Any suggestions for gear oil? (Brand name, etc) - BTW I'm in Canada