5-speed shifter bushing-- TOAST!

Engine, Transmission and related drivetrain.
Post Reply
User avatar
SteveEdmonton
Supporter
Posts: 580
Joined: 27 Aug 2010 13:20
Location: Edmonton, AB

5-speed shifter bushing-- TOAST!

Post by SteveEdmonton »

At the risk of hogging this forum completely, I've got another issue to run past the jury. The 2-piece plastic bushing that locates the horizontal pin through my shifter (this is a ZX 5-speed-- I think I called it an FS5W71A in another recent posting, but actually it's a 71B) has completely disintegrated. All I've got are jelly-like granules.

It must have happened pretty quickly since I've only put about 500 miles on the drivetrain since a fresh rebuild (engine and tranny). I'm fairly certain that I actually did put the bushings in when re-assembling everything. :? I certainly didn't notice anything amiss in the shifting until just a day or two ago, when I became aware of a rather disconcerting vagueness, accompanied at times by a rather abrupt "jumping" into or out of the intended gear. It was probably one of those things that develops so slowly that you don't notice it-- until all of a sudden you do!

Anyway, by today the shifter was actually rotating on its own (cockeyed) axis, which definitely shouted that something was wrong. So I pulled up the boot and sure enough, no bushings to be seen. Upon disassembling the mechanism when I got home, granules were all that could be found.

Is this a known "issue"? I'm sorry I didn't think of taking a photo before I cleaned up the bits, but they were not dry and hard like "ground-up" plastic usually is. Instead, they seemed relatively soft and rounded in shape, like something that's been chemically attacked or dissolved.

Right away I'm wondering about the tranny oil I'm using-- GM Synchromesh. A number of us have been raving about it (for example here: viewtopic.php?f=30&t=27676&p=243853&hil ... sh#p243853) for its extraordinary properties within the gearbox. Of course that's where it ought to be staying anyway, down below within the case, not finding its way up to the top of my shifter mechanism-- and I don't recall these bushings (or the pin) being oily when I took things apart. But is it plausible that that's what "ate" these bushing pieces? Or, if not: anybody got any other ideas what might have happened here?
'71 4-door
'74 MGB-GT
'04 Miata
User avatar
okayfine
Supporter
Posts: 14154
Joined: 12 Nov 2007 23:02
Location: Newbury Park, CA

Re: 5-speed shifter bushing-- TOAST!

Post by okayfine »

No other ideas, but it is plausible that the bushings were attacked by oil. Like dissolves like. Now, the question is whether the plastic bushings were OE material, or some later aftermarket pieces that weren't engineered properly? Haven't heard this being a known issue.
Because when you spend a silly amount of money on a silly, trivial thing that will help you not one jot, you are demonstrating that you have a soul and a heart and that you are the sort of person who has no time for Which? magazine. – Jeremy Clarkson
User avatar
bertvorgon
Supporter
Posts: 11996
Joined: 04 Aug 2003 20:45
Location: White Rock, B.C. Canada

Re: 5-speed shifter bushing-- TOAST!

Post by bertvorgon »

These bushing just get beat out, maybe yours were some cheap aftermarket ones, never see oil attack the factory ones like that.

I have steel ones in mine, makes the shifting way more positive. Maybe give Specialty Engineering a call and see if Andy has any in stock. He also may have that bottom ball socket bush too, that keeps everything really precise.
"Racing makes heroin addiction look like a vague wish for something salty" - Peter Egan

Keith Law
1973 2 Door Slalom/hill climb/road race / canyon carver /Giant Killer 510
1971 Vintage 13' BOLER trailer
Post Reply