Hi Larry,
Personally I think it's too early to be considering a trans swap or even another rebuild, for several reasons.
For one, first gear syncrho is actually something you can live without pretty easily.... Just ask all the TR2/3 owners who never enjoyed it to begin with! I drove my TR4 with a very iffy 1st gear synchro for sevearl years. I learned to double clutch and use 2nd gear from relatively low speeds anyway. No real problem driving the car w/o 1st gear synchro.
Usually a simply worn out 1st syncrho will not cause any further harm to the gearbox. It would be more of an issue if 2nd, 3rd or 4th synchro were the problem. To me it would be a bigger concern if it were a very sudden failure, possibly combined with other symptoms like gearbox noise.
One thing I'd suggest you do right away is drain the gearbox oil. Be sure to use a clean pan to catch it and take a close look for a lot of grey or bronze particles floating in the used oil. These might indicate rapid wear of bushings/bearings/shafts (grey) or synchros (bronze). Larger chunks of metal, steel or bronze, are indicative of more serious damage inside the gearbox. If you let the oil sit overnight, particles and sludge will settle to the bottom and be even more obvious when the oil is poured off into another container. It might be a good idea to put the used oil and sludge in a clean container and keep it so you can show it to any mechanic who might work on the gearbox.
Be sure to use the right type of oil when you refill the gearbox (non-detergent, 30 to 40W racing motor oil would probably be best, if the J-type OD is recently rebuilt).
I know some TR6 don't have a gearbox drain plug (unless one has been added), in which case it is harder to analyze the oil like this. But, since you have an OD, that might serve to drain the oil.
Fresh oil just might help things work better, especially if the current oil has been in there since the rebuild and there was some initial wear and tear while the box and OD were breaking in. This might lead to contaminated oil and poorer lubrication. A lot of gearbox/OD rebuilders run freshly rebuilt units on some sort of bench setup for as much as an hour or two and then change the oil, for just this reason. Do you know if that was done when it was rebuilt?
If it's just the first gear synchro needing repair, that would usually be a relatively easy and inexpensive thing to have done. I seem to recall there have been some issues with poor quality replacment synchro parts, perhaps that's the case on your car.
If just recently out of warranty, you could still talk to the mechanic who did the job previously, if you felt you could trust them. They might make it right, even though warranty has expired by a little bit.
It's also possible that one of the selector forks is bent or the linkage is out of adjustment, too. These would also be relatively easy fixes, too.
Sounds like you no longer have good feelings about working with the original mechanic. So, beside his Toyota conversions, be aware that Herman Vanden Akker (HVDA) also works on the TR gearboxes and might be able to advise you, or give you the name of someone else nearby who can. Herman is in SoCal, I seem to recall, perhaps near you? (Shipping alone would be pricey sending a complete 120 lb. gearbox/OD to John at Qauntum Mechanics on the East Coast, who is the other top source for TR g'box repairs, IMO).
One other thing. Difficulty getting into first gear is not always a synchro issue. It can also be a sign of a clutch problem, such as excessive wear/adjustment needed (which is not possible on stock TR6 setup, but there are aftermarket adjusters available), or the dreaded failure of the taper pin holding the fork to the cross shaft. It can also be a sign that the hydraulic system isn't giving full movement (5/8" or more at the lever, if I recall correctly) and there is a leak or air in the MC or SC, especially with TR6 stock setup that has little margin for error.
In these cases, the clutch simply isn't disengaging adequately. Very often a first sign is also that 1st gear becomes difficult to engage, just like a failing synchro. Repair can be relatively inexpensive to moderately expensive, but no where near the cost of a gearbox rebuild or conversion.
Hope this helps. Keep us posted!
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