hard shifting with new slider

[PEPPE]

i was rebuilding a friend's trans. it is a narrow fork 63 i was installing a nos slider non 3/4 but while adjusting on the fixture, it appears that it is impossible to get in/out of gear without rotating the mainshaft. there is also a new fork. is it better to use a lightly worn fork? this appear too precise and binds. bearing carrier has very little play.
i believe that some road will cure, but how much is too much? is there any trick that can help? maybe some massage to the sides of the tooths of the inner part of the slider?
thanks

[Pablo2]

It's always a good idea to do fit check of all matching parts before assembling onto shafts. Sleeves on hubs, forks in grooves, sleeves onto gears, etc (always without springs & energizers) .. that's the only way you'll ever spot a burr, dent, or some other imperfection requiring file work.

Do you have the nosecone installed, pressing the mainshaft bearing flush into intermediate housing? What's the clearance of the fork in the groove? Ever dropped the forks? (New 4mm forks? Hmm .. wish I had a source for those.)

[PEPPE]

good points, thanks. about the fork it is only a vw brass one, nothing interesting. however i had totally dismantled it again and will make some other checks. i wil also rebush the housing, so i will be sure that all is perfectly squared.

[Pablo2]

I had a couple new brass forks at one time and tossed them out. May as well eliminate all potential breakage problems.

[PEPPE]

i've seen them run well on street engines. how many og trans had them ?

[Pablo2]

VW changed from brass to steel for a reason .. too high a failure rate. All it takes is one ham-fisted shift to break a tab off, so whether the failure rate is 5% or 30%, the point is they became a recognized weak link for VWs back in the '60s.

I happen to like brass forks. They don't break in the Porsche street transmissions I'm familiar with (bigger parts than VW). But once we introduced dogbox conversions for Porsche transmissions, we had to eliminate any brass or aluminum alloy forks in those models and replace them with chromoly, cast iron, or at a bare minimum HD T6 aluminum forks. In the first test year of our conversions, a stock 1st/2nd fork cost one of our customers a critical ALMS race in which he had been leading the pack.

[PEPPE]

so vw changed from steel to brass and then returned to steel? earlier ones appear all in steel...

[Pablo2]

I believe this is correct. They must have tried brass forks for a few years because they're easier / cheaper to manufacture.

[PEPPE]

or maybe also that they were fighting wear. late ones are also sprayed and contact surface is less...
brass ones seem to be good toward wear, but prone to break....

[Pablo2]

It's worth noting that later 5mm "steel" forks aren't made to the same standard as early forged 4mm steel forks.