Taurus Car Club of America : Ford Taurus Forum banner

1 - 20 of 20 Posts

·
Registered
Joined
·
332 Posts
Discussion Starter #1
I was just wonderig if someone can help me understand this better. What causes excess heat in transmission:

1. Is the heat only caused by gear shifts(up/down) or also by the churning of fluid in the tranny.
So, the question is will Idealing in Traffic, with no gear shifts cause heat to build up in tranny ?

2. Driving in D, not (OD) for a long time. Like 30-40 miles at speed less than 50 mph.
Since driving in D, causes engine to rev higher, does this cause the tranny also to work harder? So, does it build up excess heat ?

3. Does the TC lock in D also or only in OD ?

Kindly add more points which cause the heat to build up in Tranny.
 

·
Premium Member
Joined
·
14,126 Posts
Most heat comes from the torque converter churning the fluid. This is one reason it is important that the converter locks at highway speeds.
 

·
Registered
Joined
·
332 Posts
Discussion Starter #3
QUOTE (SHOZ123 @ Jun 3 2009, 10:22 AM) index.php?act=findpost&pid=729905
Most heat comes from the torque converter churning the fluid. This is one reason it is important that the converter locks at highway speeds.[/b]

Shoz.
1. Does the torque converter churn fluid when idealing in traffic with shifter in D. or only when I apply gas ?

2. Does the TC locks in D ? If it doesn't, so is it churning fluid and generating heat all the time its driven in D ?
 

·
Premium Member
Joined
·
902 Posts
QUOTE (ab_sood @ Jun 3 2009, 02:07 PM) index.php?act=findpost&pid=729938
QUOTE (SHOZ123 @ Jun 3 2009, 10:22 AM) index.php?act=findpost&pid=729905
Most heat comes from the torque converter churning the fluid. This is one reason it is important that the converter locks at highway speeds.[/b]

Shoz.
1. Does the torque converter churn fluid when idealing in traffic with shifter in D. or only when I apply gas ?

2. Does the TC locks in D ? If it doesn't, so is it churning fluid and generating heat all the time its driven in D ?
[/b][/quote]

Torque converter ALWAYS churns when not locked. It ONLY locks at 'straight and level' type of cruising with minimal load.
Think of a locked torque converter like a clutch that is engaged. If you don't hold in the clutch pedal down in traffic, the motor will stall. If the torque converter DOESN'T unlock at lower speed, it will at least lug the motor, at stop it will stall it.
Yes, the torque converter is always churning and thus creating heat much of the time while in 'D', if it doesn't lock up at highway speeds when you are spinning faster than just sitting in traffic, it will create even more heat.
 

·
Premium Member
Joined
·
8,433 Posts
Heat is always caused by fluid going thru restircted orifices under pressure.

Delta P , pressure drop or differential pressure which are all the same thing cause heat.


Mike
B)
 

·
Premium Member
Joined
·
902 Posts
QUOTE (mwt @ Jun 3 2009, 05:48 PM) index.php?act=findpost&pid=729980
Heat is always caused by fluid going thru restircted orifices under pressure.

Delta P , pressure drop or differential pressure which are all the same thing cause heat.


Mike
B)[/b]
Easy, tiger.

Most of the owners on this list are hard pressed to change their own oil. You're getting dangerously close to real engineering terms here :rolleyes: :lol2:
 

·
Premium Member
Joined
·
14,126 Posts
The TC should lock at high way speeds in 4th and if slowly accelerating in 3rd. You can tune it to lock at WOT too in both 3rd and 4th.

The TC is the cause of ~60% of the heat generated. More than likely if the TC is locked then there is no heat build up problem.

This is coming from someone who went 3 years with the TC not locking due to a final drive gear change. In mountain driving the fluid temp with three sorry coolers still got over 250F.

With the Gen 2 SHO cooler and my tuning it seldom gets over 150F even in +90F temps and hard driving.

At Gingerman where the tranny is in 2nd most of the time the fluid will get to 300F when the temps are in the mid 90Fs even with the Gen 2 cooler.
 

·
Registered
Joined
·
332 Posts
Discussion Starter #9
so I guess, while driving in D(3rd gear), at speed above 35mph the TC should lock ?

300 F in 2nd gear.. wow.. do all the trannies heat that much ?
or this is special characteristic of AX4S / AX4N.
 

·
Premium Member
Joined
·
14,126 Posts
Yes it the should lock above 35 and at a steady load in 3rd. 3rd is very hard to tell when it locks and unlocks though.

Going around the road course at Gingerman I'm either at WOT or engine braking and rpms between 5000-7500. Only two places on the course where it shifts into 3rd and that is only for <10 seconds before I downshift again.

Tough course for an ATX with the Taurus stock 3.77 gearing. It was better with the 3.98 gearing.
 

·
Premium Member
Joined
·
5,111 Posts
QUOTE (Zenriddles @ Jun 3 2009, 08:02 PM) index.php?act=findpost&pid=730005
QUOTE (mwt @ Jun 3 2009, 05:48 PM) index.php?act=findpost&pid=729980
Heat is always caused by fluid going thru restircted orifices under pressure.

Delta P , pressure drop or differential pressure which are all the same thing cause heat.


Mike
B)[/b]
Easy, tiger.

Most of the owners on this list are hard pressed to change their own oil. You're getting dangerously close to real engineering terms here :rolleyes: :lol2:
[/b][/quote]
Condescending much?
 

·
Registered
Joined
·
332 Posts
Discussion Starter #15

·
Premium Member
Joined
·
14,126 Posts
The TC is still turning. It just is decoupled inside the transmission and there is no power flow.
 

·
Premium Member
Joined
·
8,433 Posts
QUOTE (Racer X @ Jun 5 2009, 09:58 AM) index.php?act=findpost&pid=730345
QUOTE (Zenriddles @ Jun 3 2009, 08:02 PM) index.php?act=findpost&pid=730005
QUOTE (mwt @ Jun 3 2009, 05:48 PM) index.php?act=findpost&pid=729980
Heat is always caused by fluid going thru restircted orifices under pressure.

Delta P , pressure drop or differential pressure which are all the same thing cause heat.


Mike
B)[/b]
Easy, tiger.

Most of the owners on this list are hard pressed to change their own oil. You're getting dangerously close to real engineering terms here :rolleyes: :lol2:
[/b][/quote]
Condescending much?
[/b][/quote]


Not at all Hamal. At least not as much as I have seen you do

Mike
B)
 

·
Premium Member
Joined
·
5,111 Posts
QUOTE (mwt @ Jun 5 2009, 05:38 PM) index.php?act=findpost&pid=730414
QUOTE (Racer X @ Jun 5 2009, 09:58 AM) index.php?act=findpost&pid=730345
QUOTE (Zenriddles @ Jun 3 2009, 08:02 PM) index.php?act=findpost&pid=730005
QUOTE (mwt @ Jun 3 2009, 05:48 PM) index.php?act=findpost&pid=729980
Heat is always caused by fluid going thru restircted orifices under pressure.

Delta P , pressure drop or differential pressure which are all the same thing cause heat.


Mike
B)[/b]
Easy, tiger.

Most of the owners on this list are hard pressed to change their own oil. You're getting dangerously close to real engineering terms here :rolleyes: :lol2:
[/b][/quote]
Condescending much?
[/b][/quote]


Not at all Hamal. At least not as much as I have seen you do

Mike
B)
[/b][/quote]
I was quoting someone else there, killer. :mellow:
 

·
Premium Member
Joined
·
14,126 Posts
Yes it runs cooler as long as the rpms are low. But at low rpms you aren't generating much heat anyway.
 
1 - 20 of 20 Posts
Top