Wierd WOT 1-2 shifting.Replace 1-2 Hub/slider or just motor mount upgrades?

[my_gst95]

Daily driving my 90gsx tranny is perfect. But when I go WOT after a launch and need to go into 2nd, its like the shifting point is not only farther down, but its very difficult to get into. Hard to explain but heres a dummys drawing:

Daily Driving:
<1st gear>==N==<----2nd shift room play--->

WOT
<1st gear>=========N=========<2nd>

It's REALLY killing my 1/4 times (22psi, 12.8@113mph, 1.89 60'). I literally have to wait for the RPM to drop down to about 4500rpms to shift correctly and thats MAJOR downtime from my 8k redline. Would motor mounts help prevent this (perhaps the engine/tranny is shifting too much stretching the shift cables) or is this a sign of a bad hub/slider? I did a rebuild on the tranny recently, but only the synchros were replaced.

my_gst95

 

[pneumo]

It could be some of both. For sure, check your mounts.

Most of the time just replacing the syncros only helps a little. Like you said, the hub/slider wears out, too. Plus the side gears loose their edge and don't grab as well. The 90 has a single syncro 2nd gear, so it's not going to shift great even with all new parts. Take care of the little things, too, such as base plate shifter bushings, skate bearings in the cable ends, fine tune the cable adjustments, and replace the horsecock shift handle with a proper low profile shift knob. It'll help.

I almost forgot, there are some rubber grommets holding the shift cable bracket on the tranny. That'll cause some slop. Replace them with solid metal washers. You should need two different sizes, a small one that fits in the hole in the bracket, and a thick large washer on the side of the bracket. Make sure it can't slip when you're yanking hard on the shifter.

 

[my_gst95]

Ah thanks for the tips. I figure if I can do all the things you listed, maybe I can postpone the Shep tranny a little bit longer. I just can't justify spending that much if the tranny shifts fine under regular driving situations. I did notice the engine shifts alot when my idle was super lumpy after dropping in the cams, so I guess I'll do the mounts first and go from there.

my_gst95