Subject: [TR] Strange TR3 OD issue

From: Alexander Delis <[email-masked]>
Date: Fri, 11 Jul 2014 20:33:26 -0400

Hello all

I am having a very odd problem with my TR3 OD.

I will start from the beginning.

The box is a TR3 OD with no syncro into first. It was rebuilt by John Esposito
at Quantum Mechanics about 4 years ago.

Last summer, I was having difficulty getting the OD engaged. I would have to
sit with my foot off the accelerator for 5-10 seconds before it would engage.
At the end of the summer, it started leaking copious amounts of oil  (like a
quart every 50 miles or so).

I decided this needed to be sorted out this summer.

We pulled the transmission and I took it to John to work on while I waited (he
was very good about making an appointment to do this). He disassembled
everything, put in all new gaskets and seals, and ran it up to check it. He
found the pressure was a bit low and put shims in to bring the pressure up and
all seemed OK.

I brought it home, we put the transmission back in the car and now it will go
right in to OD. The problem is, when you get to about 3K RPM it will pop out.
If you leave the overdrive switch engaged, it will pop back in when the RPM
drop to about 3.6K.

The really odd thing is that this ONLY happens in third and fourth. It works
perfectly in second. I have tried to get it to pop out in second using
everything I could think of and it would not.

If I drive it for a while, the RPM it will pop out of OD will decrease e.g. it
will pop out at 2.7K and back in at 3.2K.

It no longer leaks oil and is full ( I just checked it again.)

I am using straight 30 weight oil as recommended by John Esposito.

The only thing I can think of that is common to third and fourth is that they
use the same lockout switch, but I don't know why it would pop out at a
particular RPM EVERY time.

Any ideas?

TIA

Alex

1958 TR3 TS33884LO
1968 GT6 KC10303

** [email-masked] **

Archive: http://www.team.net/archive

---

From: Randall <[email-masked]>
Date: Sat, 12 Jul 2014 0:53:35 +0000

> particular RPM EVERY time.

Vibration sensitive?

Probably my first step would be to connect a voltmeter/DMM to the OD relay, and take a test ride.  If it shows that the relay drops out when the OD does, you know it's an electrical issue.  Then change the connection so you can see the lockout switch at work.  Again, if it drops out when the OD does, you've found your culprit.

Might not be the switch, but the wires/connections to it.  One of the Stags would drop out for no apparent reason (although it was much more random) and it turned out that the quick connect to the solenoid was very slightly loose.  Not loose enough to fall off, but loose enough to sometimes lose contact.  So, if the above test does show the relay is not being grounded through the lockout switch, the next test might be to remove the tunnel and repeat the experiment with the meter connected directly to the terminals on the switch.

Randall

---

From: Jeff <[email-masked]>
Date: Sat, 12 Jul 2014 10:11:49 -0400

> I am using straight 30 weight oil as recommended by John Esposito.

Non-detergent, right?

---
This email is free from viruses and malware because avast! Antivirus protection is active.
http://www.avast.com

---

From: Alexander Delis <[email-masked]>
Date: Mon, 14 Jul 2014 20:25:52 -0400

Found the problem

It was the relay.

Don't know why OD 2nd worked perfectly and 3/4 did not- can only assume the
3/4 ciruit was drawing more current but have no idea why

Works fine with the new relay

Thanks for all of the suggestions

Alex

On Jul 11, 2014, at 8:53 pm, Randall <[email-masked]> wrote:

> Probably my first step would be to connect a voltmeter/DMM to the OD relay,
and take a test ride.  If it shows that the relay drops out when the OD does,
you know it's an electrical issue.  Then change the connection so you can see
the lockout switch at work.  Again, if it drops out when the OD does, you've
found your culprit.
>
> Might not be the switch, but the wires/connections to it.  One of the Stags
would drop out for no apparent reason (although it was much more random) and
it turned out that the quick connect to the solenoid was very slightly loose.
Not loose enough to fall off, but loose enough to sometimes lose contact.  So,
if the above test does show the relay is not being grounded through the
lockout switch, the next test might be to remove the tunnel and repeat the
experiment with the meter connected directly to the terminals on the switch.

1958 TR3 TS33884LO
1968 GT6 KC10303

---

From: Randall <[email-masked]>
Date: Tue, 15 Jul 2014 0:47:55 +0000

> Works fine with the new relay

FWIW, I found that the relay lasts much longer if you add a suppression diode across the solenoid (from the relay output terminal to ground).  Before adding the diode, the relays were going intermittent within just a year or two, regardless of whether I used an expensive reproduction relay or a cheap automotive relay.  That has to be 20 years ago now, and the same cheap relay has been working fine ever since.

Too soon to say if it will help or not; but when the pull-in contacts inside the solenoid failed recently, I added a diode there, too.

These are just cheap 1N4004 diodes from Radio Shack.  A 3-pack is $1.50; I got 25 of them for $3.50.

Randall