> From: Brian Kemp [SMTP:bk13@earthlink.net]
> Sent: Thursday, June 04, 1998 4:37 PM
>
> Regarding overdrive and the transmission switches: To verify that the
> switches work, or determine when they engage/disengage try this. In a
> quiet location, turn the ignition to the on position without starting
> the car. Engage the overdrive switch. Shift into various gears and
> listen. You can hear the relay switching. TURN OFF THE KEY.
>
>
Just to clarify (since I am the one who began this thread)...
My (J-type) O/D works as it is supposed to along with all the switches. The
debate began when I posted a question as to why if I shift from 3 to 4 (with
O/D engaged) I get a minor grind. If I make the same shift with O/D off, no
grind. Also on my car (stock factory gearbox as confirmed by the build
certificate), the solenoid does NOT remain energized when the shift lever is
between 3 and 4 gears. This is the way the top cover switch is designed to
work on my car. However, the O/D oil pressure remains well above the minimum
required to engage the O/D (470 psi normal operation, 450 psi during the
shift).
So based on the feedback from several listers (Barry Schwartz, Dave Massey &
Andy D primarily, sorry if I missed any others), it seems that several
conclusions can be made:
1. Triumph had several designs for solenoid activation switches. Some cars
used a mechanism whereby the solenoid remains activated the whole time the
shifter is in the plane of the O/D enabled gears. Others (like mine), only
activate the solenoid when the shifter is one of the enabled gears, not
between gears.
2. Since I recently did some work on my clutch linkage, I suspect the
culprit is that I have shortened the throw of my clutch. Although I thought
I was shifting from 3 to 4 at roughly the same rpm's in O/D and in direct
drive when I conducted my "test", perhaps I did not match rpms closely
enough during my test. I will try this again this weekend.
3. The pressure readings I have suggest that even though the solenoid loses
power during the shift, the O/D does remain engaged. And I certainly feel no
jerky sensation after the shift as if the O/D re-engages after I
successfully shift from 3 to 4 gear. So I think the grind is caused by
something else (remember, it grinds when O/D is engaged only).
4. Others who have J-type O/D's in their TR6s also get the grind. While some
said they do not get the grind, those who do are the majority. Perhaps this
is a normal behavior. I just don't recall my car doing it in the past.
Anyway, that is brief a summary of the thread so far.
Cheers,
Peter Zaborski
76 TR6 (CF58310 UO)
Calgary AB Canada
> Brian Kemp
> 72 TR6
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