Dear forum-members,
This topic & thread was mentioned on the DTLC-list, and after some debate I also asked Rodney from AutomaticTransmissions for his opinion about reversing the lockup, as I have always been very fond of engine braking with a diesel....below the comments he allowed me to post to this forum as well.
Bottom line: could work in a lighter vehicle for incidental or low power demands, but towing & heavy continuous use seems out of the question.
(note that his latest products involve lockup for lower gears as well, *and* that it is good offroad-policy to shift an auto into low-range, to keep the lockup active, and the heat away from the torque converter in the first place (also by revs/gearing of course).
(btw, most of this DTLC-thread & some earlier notes I had collected about slushbox lockups can be found here:
http://www.a1.nl/phomepag/markerink/lockauto.htm )
xxxxxxxxxxxxx
From: "Hudson-Davies Family" <rodtina@optusnet.com.au>
To: <w.j.markerink@a1.nl>
Subject: Re: AT Valve Body replacement and Lock up
Date: Thu, 17 Jun 2004 16:04:19 +1000
Hi Willem it's Rodney here from Wholesale Automatics. First of all thanks
for bring this message to my attention. I have read all the responses and
even gone to the web site message board that started this and read through
all of there messages. Where do I start? I would first of all like to let
you know that removing a Lock-Up from any convertor in a vehicle that is as
heavy as a Landcruiser or Nissan Patrol will shorten the life span of the
transmission due to over heating especially when towing. This can be as bad
as only getting 5,000Km out of your transmission after removing the Lock-Up.
It can't be done, I know! I have already been there and done that years ago.
I have a full time job trying to stop these things from over heating at the
best of times. The worst offender is the A440 hydraulic transmission but
they all do it to some degree because of the small size of the convertors
that are used in all Landcruiser and Patrols. You can not afford to remove
one of the major components that keeps the transmission within an expectable
heat range ( 60-120C ).
We have built many low stall convertors and it took as 3 years to work out
how to lower the stall speed without having to enlarge the convertors outer
circumference or having to remove the Lock-Up plate. I tell you this with a
passion because we have reconditioned, modified and changed these
transmissions so much over the last several years that I know them inside
and out. I know how they will respond when you fit a Turbo or do a V8
conversion. I know what sort of a heat to expect from a certain
transmission on a 34 degree day towing a 24 foot long caravan with a
standard engine going through the mountains or even across the Nullarbor.
Just as a twist to this story and to prove a point I have just got off the
phone to a customer of mine that has a GU Patrol and noticed lack of power
in the engine, struggling to maintain 80 Km and a transmission that was
getting over 125C on a flat stretch of road between Echuca and Deniliquin
towing a caravan. We had fitted one of our standard reconditioned
transmissions, Extreme valve bodies and our new transmission oil temp gauge
kits several months ago for his trip to the Cape and also left him with
sticked instructions to pull over if he ever got to 140C. He was concerned
at 125C and rang me, I asked him to change from Gas to Petrol and with in 4
minutes the transmission was back down to 80C he speed was back up to
cruising speed and had all his power back. What had happened was that he
was holding his foot on the go peddle so much that the convertors Lock-Up
was wasn't getting a chance to engage. No Lock-Up and the transmission was
in trouble straight away! Needless to say he has a problem in the gas system
some where (Should of asked him if lack of it was the problem!) I'll find
out later.
We can lower the stall speed of the convertor without having to remove the
Lock-Up and in the lasts month or two decided that we no longer do this
unless an V8 Conversion is being done, In this case the Low Stall Convertor
is a must otherwise the convertor will overheat due to the high stall speed.
The more power you have the higher the stall speed goes. We have instead
developed a Lock-Up Manuel Over-Ride Control Relay, Switch and wiring
harness that comes ready to install into all Toyota Land Cruiser and Nissan
Patrols. Please see Link to news release for full details. Reducing the
stall speed of the convertor behind a factory fitted Engine resalts in
sluggish take off's, The stall speed drags the engine Rpm down to far on a
Std factory engine. We spent a long time trying to find the fine line
between better engine braking and sluggish take off's. We instead designed
the lock-Up Over-Ride and got the best of both worlds. Steep down hill
docents with 100% engine braking and no overrunning what so ever. One side
effect if you can call it that is that the A442F transmissions will require
the Extreme Valve Body as well, The Patrols don't need the valve Body for
this and I haven't done one for the A750F 5 Sped yet. Looking for a
guineapig!
In my eyes he perfect heavy duty accuracy pack for both the Land Cruiser and
Patrol Automatic Transmission is:
Extreme Recalibrated Valve Body:
http://www.automatictransmission.com.au ... ewsId=4651
http://www.automatictransmission.com.au ... ewsId=8169
http://www.automatictransmission.com.au ... wsId=11360
And the A750F 5 Speed that I have photos of but not made a news release for
yet.
I think Greg Goulden would kill me if I didn't give it to him first as
promised. Works great but!
Temp Gauge Kit:
http://www.automatictransmission.com.au ... wsId=12031
Lock-Up Manuel Control Unit:
http://www.automatictransmission.com.au ... wsId=12101
Large Oil Cooler if not already fitted:
Synthetic Transmission Oil:
If you or anybody have any questions regarding this matter then please feel
free to ring me direct on 0415393755. As you can imagine there is no
possible way I can explain all the fine details without boring every body to
tears. Please feal free if there is something I did a useless job of
explaining.
![Smile :)](./images/smilies/icon_smile.gif)
And in the case of Greg feel free to edit the links out. I
will understand!
Kind Regards
Rodney Hudson-Davies
Wholesale Automatic Transmissions