[TR] Transmission internal pressure question

[Mark Hooper]

Hi Randall & Ken :

Thanks for the replies. I have been all over the shift tower on my J-type and
my A-type units. I do not see a vent hole. Randall's attached image makes it
seem that the factory simply drilled a hole between the reverse and 3rd/4th
selector rods (leftmost and middle). The placement seems rather specific since
the aluminium is thinner almost everywhere else. I assume the place was chosen
to give a longer pathway to reduce oil slopping out the breather hole.

I am now thinking that when my mechanic made up my transmission, he did so
using a shift tower without a breather.

The cure would then be to pop off the tower and make like a US politician.

Now trying to get maximum detail on placement and routing of hole. (Thanks for
that photo Randall, it gives me placement, but can't tell if it is a simple
vertical hole or something more complex.

Cheers,

Mark




________________________________________
From: triumphs-bounces at autox.team.net [triumphs-bounces at autox.team.net] On
Behalf Of Randall [tr3driver at ca.rr.com]
Sent: May 2, 2010 12:19 AM
To: triumphs at autox.team.net
Subject: Re: [TR] Transmission internal pressure question

> Is a TR6 j-type tranmission supposed to have venting, or
> internal pressure?

Well, both actually <G>

>  I see now that the
> transmission is
> weeping oil from the seals around the shifting rods

A common problem even without blocked vents.  The seals being sold today do
not fit the cavities in the cover snugly. Herman mentioned machining spacers
from brass to fill the gap, but I was able to source some Teflon backing
rings that did the trick for me.

> I think the fellow who rebuilt the transmission and put in
> the nice unit from
> Laycock Rebuilders used 80w90 gear oil. This I have been told
> is a no-no.

Hard to go very wrong with the factory-recommended lubricant!

> Is there a vent hole in the transmission somewhere that might
> be blocked up?

I believe there should be.  Not sure where it was on earlier gearboxes, but
by the time the J-type came in, it was on the top cover near the front RH
corner:
http://tinyurl.com/23kmev4

There is even a factory service bulletin about checking that hole, if the
rear seal is leaking.

> Certainly I used to use 20w50 in the a-type and did not have
> this leaking.

A-types have a big vent in the OD body.  I don't believe the J-type does,
instead it relies on the gearbox vent.

Randall