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T90 gearbox problem help please

Posted: Mon Jun 27, 2011 1:19 pm
by Invicta
I have column change 4 speed T90 in my 1975 Mitsubishi Model J26 Jeep.

It is relatively difficult to get 2nd gear to engage and so I was wondering if anyone had any suggestions?
All other gears engage and disengage well enough.

Or might someone be able to recommend a place that would take the box out, recondition it and put it back in.
Preferably somewhere around the west midlands or south west as I live in Tewkesbury.

All help will be very much appreciated,
Bern

Re: T90 gearbox problem help please

Posted: Tue Jun 28, 2011 7:45 am
by pryantcc
HI Bern,
I am not familiar with your particular gear box, but it sounds like your synchronising mechanism is kaput. It's hard to describe, but in the old days before synchromesh, you used to have to do it yourself. The trick when changing gear was to press the clutch, take it out of gear, release the clutch with the car in neutral, poke the throttle to spin the engine (and cogs attached to it) up to match the speed of the wheels (& the cogs that are attached to them), then clutch again, and slip the car into the next gear. Synchromesh does that for you by speeding up or slowing down the relevant cogs before they come into mesh with eachother. Since first to second is the most frequently used gear-change, its the one that wears out first!

Is it easy to select 2nd when the engine is turned off and the car at a stand-still?

Re: T90 gearbox problem help please

Posted: Tue Jun 28, 2011 8:50 am
by JPB
I think that the key to this lies in the words "column change". Check every one of those bushes from the column right back down, chances are that slack there would do this.
I had a CA Ice cream van which demonstrated that double-declutching doesn't get around worn bushes on column changes, the thing was transformed with new ones. ;)

You're lucky in that Toyota can still supply bits, I had to make bushes for the CA from Magic Polymorph, though that's really good stuff if you can't get the bits.

Re: T90 gearbox problem help please

Posted: Tue Jun 28, 2011 10:16 am
by spiderbloke
What on earth did you do with an Ice Cream Van in Northumberland John? :D

Was that for the couple of days per year when the sun burns the clouds off?

Re: T90 gearbox problem help please

Posted: Tue Jun 28, 2011 11:21 am
by JPB
:lol: That was during a couple of hot, 1980s summers when we had temperatures into the high 70s most of the time between May and September, it helped supplement Subaru's excuse for a salary, at least until International Motors realised that my term at uni had finished and that I should have been in work every weekday. :oops:

Re: T90 gearbox problem help please

Posted: Tue Jun 28, 2011 2:16 pm
by Invicta
Spot on.

Yes it is easier to engage 2nd when the Jeep isn't running and to get around it I do the "double declutch two step" as I remembered that's how my dad used to do it in his original cars.

I'll also check the bushes for slack as that can't be helping matters either so I'm off to Goggle Magic Polymorph.

Many thanks for such quick and helpful replies,

Bern