TR2/3/3A Reverse shift rod stuck

[jfarris]

Beautiful weekend for the second annual historic races at Barber Motorsports Park in Birmingham - until. As I tried to back into my parking spot on Sunday, the gearbox would not go into reverse, though it felt like it did. Car was not in any gear, but at least it would roll.
1956 TR3 with a TR4 gearbox with A overdrive.
I took the shift lever out and saw that the reverse shift rod was just forward of neutral. No reasonable amount of force would get it to move. The 1/2 and 3/4 shift rods appear to be in the normal neutral position and would not move. I'm going to remove the top cover of the gearbox with the tranny still in the car. Any educated guesses about what I'm going to find?
Thanks,
Jim

 

[TomMull]

One guess might be a broken or loose pin that holds the shift fork to the shaft.
Tom

 

[Marvin Gruber]

Call Brad!
Marv

 

[thechileman]

I have what you described happen several times on my tr4. I remove the shifter, and use a large screwdiver to move the shift rods. It sometimes takes a pop with my hand on the screwdriver handle to get things moving again. It seems to happen when I don't have my shifter all the way lifted up when I am putting it in reverse. Has happened 3 or 4 times in the 8 years I have owned the car. The first time I pulled the top cover, the other times I did as described above. The transmission operates fine otherwise.

 

[clanofwolves]

I've had a similar issue at times: sometimes it seems I cannot get into but a gear or two, but when I begin to let out the clutch, regardless of throttle it Boggs down to stall without movement. A bit of moving around the shifter to seemingly "loosten it up" and it works fine. I haven't a clue why????

 

[sp53]

When you get the top cover off take a look at the forks, they are made of brass and wear thin after time. I think tr2 through tr4 use the same forks, but I could be wrong. The forks are not difficult to remove and the newer they are it helps with shifting.

 

[TR3driver]

Shift forks weren't even the same across all TR3A; and the 1/2 and reverse forks changed again when the TR4 was introduced (also some TR3B).

For thechileman and clanofwolves, the first thing I would check is the shift interlock in the top cover. Being totally invisible with the shift rods in place; it is easy to put it together wrong, or have the top cover damaged in that area without knowing it. It is what ensures that, no matter what the operator does in terms of sloppy shifting, there is never more than one shift rail away from neutral at the same time.

But that doesn't seem to be Jim's problem. My guess would be that the pivot bolt came loose or broke, but that's just a WAG.

 

[jfarris]

Thanks to all for the ideas and possibilities.
Initially, after the shift lever was out, I tried some force on the shift rod, but didn't want to break anything. This past weekend, I finally talked to the rebuilder and took the cover off. The prime suspect was the shift interlock in the top cover, but it was fine. No broken or stuck parts. TR4 full-synchro tranny, it appears that the reverse rod jumped off the peg on top of the lever (internal) and was behind the peg, thus holding the shift rod forward but not far enough to engage reverse gear. Looked impossible, but I couldn't find any other explanation. Needless to say, I took a very long test drive and put the car in reverse many times before I put that tranny cover back on.
Thanks for all the ideas and support,
Jim