[Shotimes] MTX shifting difficulty hypothesis

[Carl Prochilo]

Justin,  I'm far from being a transmission expert, but I do know that the
transmission has mechanical logic to gate and ungate gear selection through
the use of blockers and synchros.  When you try to downshift from a high
speed, if your engine speed isn't "in the ball park", you will feel a lot of
resistance when trying to engage a lower gear.  If you fight the blockers, I
believe this has a negative effect on the operation of the tranny.

On a few occasions, I find that the blockers don't disengage trying to get
into first, so the way I get around this (and it is so routine I don't think
about it much), I'll put the shifter into second and that almost always
resets the transmission and I can get into first.

The last clutch job (using Ford parts) I got is just fine, and the shifting
is as smooth as I've known it to be for a SHO.

Carl P.

----- Original Message ----- 
From: "Justin Schick" <jschick@aafp.org>
To: <shotimes@autox.team.net>; <TechSHO@topica.com>
Sent: Monday, June 02, 2003 2:27 PM
Subject: [Shotimes] MTX shifting difficulty hypothesis


> I've been through enough clutches (and now a tranny) to start catching
> on to a trend I wanted to share. Most recently, I've posted about notchy
> shifting and hard 1st gear engagement with a new OEM clutch in front of
> my fresh MTX with quaife. Around the time I posted this, there was also
> a thread about a guy inching forward in first with the clutch depressed
> and revving the engine up. Soon afterward I noticed my car do the same
> type of thing, only in reverse at idle.
>
> My thought was the internals inside the transmission were not spinning
> down in idle, or being spun by too-close tolerances around the fat new
> friction disc. I had previously checked for cable slop but installed
> slotted a washer to shim the cable on the transmission end, thinking the
> adjuster mechanism may need help. No luck. I ordered the delrin ball &
> socket upgrade from SHONut (which showed up today) and some Redline MTL
> (used Mobil 1 ATF during the install) from Summit (showed up last week).
> I changed the fluid yesterday, which helped the slight notchiness
> between gears while moving, but not 1st gear engagement at a stop. I
> developed a workaround for that last week. Assuming the internals
> weren't spinning down in neutral, I decided to spin the engine up before
> trying 1st. After teaching myself this new driving style, viola it
> plunks right in every time. I don't know why it didn't strike me before,
> but it's just like rev matching for a downshift. Kinda.
>
> Anyway, I'm wondering if anyone with a new clutch and shifting problems
> could corroborate my results. I'm also wondering what the thickness of
> aftermarket friction discs is compared to OEM, and if the problem is
> truly a too-thick disc or something else (flywheel thickness, PP
> geometry, transmission alignment?). What do you think?
>
> Justin
> '92 SHO in KC MO, 190k and counting
> SHOTimes list info: http://www.shotimes.com/SHO1.html
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