Anyone get a chance to look at this in the Haynes manual. Don't mean to be
a pest, but I don't want to put this back together unless the solenoid is
correct. Any help would be appreciated.....
By the way, my .02 cents on the parts issue. As long as the subject
reflects what the message is and it is not a commercial dealer, who cares,
just file it.
Tom
77B
========================================
Thanks to everyone who gave me suggestions on the overdrive problem below.
I wish it was fixed, but still working on it. Some of the wiring to the
solenoid was badly damaged (sometimes open/sometimes not) and I replaced
it. Although the solenoid now gets 12v, the overdrive does not engage. I
have bypassed the lockout switch also. (thanks to the list)
I pulled the solenoid and if I apply 12v and ground the body, it will suck
the plunger in. It takes some force to get the plunger to come back out
(slap the thing against my hand). Should this be difficult to get out or
should it slide out easily once power is not applied? (Is there a residual
magnetic field that holds it in?) It seems to be in good shape.
Now for the "strange" question. The solenoid looks different from the one
in the Haynes manual. There looks to be an added part on the top of the
solenoid housing. I think I'll try to draw it...
_
_|_|_ <-------This is not on my solenoid, but it is on the picture.
| |
__|_____|__
| |
| |
| |
| |
| |
|__________|||----------
Hope that looks OK when I send it.
This is from a 77B (LH overdrive). The overdrive used to work so I have a
hard time believing the one I have is not correct. I believe it is
original. Design mod later on or something???
Confused.
I guess if it is not the switches, not the wiring, and not the solenoid, it
is the pump as many suggested before.
By the way, the list has really enhanced my enjoyment of my B. Have not
joined the local club yet, but probably will.
Sorry so long. I tend to ramble.
Regards,
Tom
tomm@ti.com
>To: "Tom McLaughlin" <tomm@ti.com>
>Date: Tue, 09 Sep 1997 09:14:06 -0700
>From: "S. L. Hower" <howersl@mailexcite.com>
>X-Sent-Mail: on
>X-Mailer: MailCity Service
>Subject: Re: Re: RE: Overdrive on 77 MGB
>X-Sender-Ip: 205.147.228.2
>Organization: MailExcite (http://www.mailexcite.com)
>
>
>Tom,
>
>There are two switches that control power to the OD.
>One on the dash, and one in the gearbox. The dash switch lets YOU switch
into OD;
>the gearbox switch only lets the OD on in the proper gears. They must
both be closed
>for the OD to engage (column switch on, AND car in 4th gear).
>
>The gearbox switch is located on the top of the gearbox, on the left
(drivers) side.
> It is a round doodad that screws into the top of the remote shifter
housing. There
>is a fibre washer under the switch.
>
>Again, the function of this switch is to tell the O/D when the car is in
4th gear
>(or 3rd and 4th with early gearboxes). As you shift into 4th, the switch
closes
>and power can flow to the solenoid (assuming the dash switch is closed
also) If
>YOU try to engage OD in any other gear, this switch will interrupt power
and the
>OD will not kick in.
>
>Over time the brass tip of the switch wears away and as a result isnt long
enough
>to mesh with the cam in the gearbox remote. As you drive, it bumps
around- in and
>out and causes this symptom. To test the switch, make sure the column
switch is
>OFF and then yank off the two wires to the switch on the gearbox and
temporarily
>jump them together with a test lead (tape them up with electrical tape).
This effectively
>defeats the gear lockout so DO NOT ENGAGE THE OD SWITCH ON THE DASH IN ANY
GEAR OTHER
>THAN FOURTH, ESPECIALLY REVERSE!! (too much torque in the lower gears or
backing
>up can trash the OD clutch.)
>
>Get the car up to speed and into 4th gear. Switch the OD on and see what
happens.
> If the OD still drops in and out, you have eliminated this switch from
the list
>of culprits.
>
>Happy hunting!
>--Scott
>
>---
>Scott Hower -> howersl@mailexcite.com
>
>73 MGB
>78 Midget
>
>>Scott,
>>
>>A while back when it would occasionally drop out another guy told me this
>>could be the problem also. That's when it stopped working all togethter
>>and I did not worry about it.
>>
>>Anyway, pardon the ignorance, but where is the lockout switch located. I
>>looked in my Haynes manual and the Moss parts list and cannot find it. I
>>suspect it is the overdrive switch listed on the transmission page (not the
>>overdrive page), but it does not show where it is located on the car.
>>
>>Little help...???
>>
>>Tom
>>
>>At 01:35 PM 9/8/97 -0700, you wrote:
>>>
>>>Tom,
>>>
>>>Check (and replace) the lockout switch that is on the
>>>transmission extension. This switch (not the column
>>>mounted affair) is what is causing the unit to drop
>>>in and out:
>>>
>>>When you apply torque (step on the gas) the gearbox is
>>>twisting the gearlever awa
>
>
>
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>
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