3rd gear in shep trans?

[justin90gsx]

i have a stg. 3 shep trans with 4 spyder diff and upgraded shift forks.

so i was driving on the freeway in my 90 gsx and i dropped down to 3rd gear going about 45-50 mph and took off boosting about 27-28 psi, and it felt great.
went into 3rd, 4th and 5th just fine.
then i coasted to the off ramp and stopped at the light, 1st and second shifted fine and so did 3rd but as soon as i let out the clutch the car shakes really bad in 3rd but it still goes??? so i had it towed and its been parked ever since.
so shifts fine and the trans works good but it shakes in 3rd gear and its kind of loud but there is no grinding..
the trans is still in the car, what could it be?
thanks! 1g awd

 

[Kolat]

So it only happens in third gear? or it started happening in third and now happens in all of them?

T

 

[justin90gsx]

only in 3rd gear. and after i did a hard pull in 3rd