2nd gear in the 70's

I have read many comments about the notorious failure rate of 2nd gear synchros in Dino and 308 gear boxes.

I bought my 1972 Dino 246GT in 1986 and it had the problem. After babying the gearbox for six months I decided to see what was wrong. Turns out that it was trivial. Dont know how many others have had the same experience but here goes:

The problem is not in the transmission! Synchros are fine!

The problem is in the cast aluminum shift gate and the aluminum shifter housing. There is a lot of spring in the shift mechanism by the time you get to the actual shift forks. Add wear, tear and transmissions set up to shift by the book; you can't get there from here. Literally! The SHIFT LEVER DOES NOT GO FAR ENOUGH FORE AND AFT!

The shifter housing and gate have screws at #2 and #3. This takes roughly 1/8" of possible throw off of each shift attempt. Since you miss #2, you never notice #3. It is just as bad. R, 1, 4, 5 have lots more possible throw or oomph when you stress the synchros. If it doesn't go, push harder; right?

The cure is to get into the gear box and re-position the 2 - 3 shift forks on their rods OR to get out your MotoTool and grind away the Gate and Shift Housing so #2 and #3 have the same fore and aft throw as R & 1 and 4 & 5.

I did the later and took off roughly 1/8" of aluminum on the housing. I went all the way to the tapped hole for the gate screws. I then cut the gate shift openings back to the countersink for the gate mounting screws. Still looks stock.

No more 2nd gear problems. This was 18+ years and 130,000+ miles ago. Still OK!

John

 

Attached are two pics of the modified shift gate and shift housing. The shift lever was cut away before I got the car. Previous owner probably had left/right problems. He also cut away the reverse detent so you can go into reverse any time you want. I know; and don't try reverse when going forward. I am very careful letting others drive the car.

I did teach both my daughters how to drive using the Dino. They used an automatic to take the test but they know how to use a gearbox wisely. I had fun, ocasional panic and lots of pride. Funny, my wife hates the car and will only drive it under extreme circumstances. She loves to ride in it, except when in a tight skirt. Oh well!

As you can see, the car is DRIVEN. I have not taken the gate off in 5-10 years and the dirt is pretty heavy in the pics. Is better now but I thought the as-is pics would be interesting.

John
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The first pic is of housing without gate. Front cutaway of casting is clearly visible, rear is similar. The shift arm base hit the housing long before the arm itself hit the end of the gate slot. I took off more than 1/8" of aluminum both front and rear.

Second pic shows gate in place and shows where a little was removed from gate itself right at screw countersinks. One of these days I will get gate re-chromed but there is little corrosion.

Car had 51,000 miles when I bought it in 1986. Has 184,000+ miles to date and still goes strong. 1972 246GT #04504. Drive it every day.

John