How do you know your tranny has oil?

[David Anderson]

Ok, if you read my "broke down in Raton" thread, I now have a deep concern to determine if my tranny has blown a line and dumped all its oil on the pavement as I roll merrily down the hiway.  Does anyone have a way to tell if their tranny has oil from the cockpit?  Temperature gauge read normal, so that's not a good indicator.  I know I have a Voith and you guys all have Allisons or others, but what is a good way to determine "trans low oil"?

David

[kyle4501]

I would think a pressure gauge as close to the pump output as practical would show when the fluid pressure is below a safe operating pressure. I'd definitely put an alarm on that one too - flashing light or buzzer.

However, is this necessary? How often does this happen? I know you got lucky with the timing of your stop relative to the hose blow-out.

I do understand the comfort of having the sensors, but I often wonder if the 'safety' devices lead to increased contempt for proper maintenance - how many of us check our car's oil at every gas fill? I know I seldom check mine - & I should know better! - because I have a 'low oil' light on the dash.

Hard to put a sensor in for every possible thing that could go wrong. . . . Then you have the added PM on the sensors to ensure they are working properly. . . .

[luvrbus]

David, I know Allison make a warning light kit for the 740 seen those on fire trucks and equipment will only come on with the engine running mounts on the pan with the engine running if oil is below that point it flashes.
I don't know if Voith makes one or not aren't those guys located in Houston off the Katy freeway.
Does the Voith pickup the temp at the torque converter housing like the Allison most of the time a Allison will show a temp rise when only a gal low or a gal overfilled sorry but I am not much help on the Voith or ZF autos


good luck

[bevans6]

One idea from the aircraft engine folks...

http://www.aircraftextras.com/LowOilSensor.htm

I have a sneaking suspicion that your trans will maintain pressure up until there is a very unhealthy level of oil, since it worked all they way into your parking spot.

Brian

[FloridaCliff]

My Spicer has a pressure sensor on the output of the filter housing.

The idiot light for that and the air always come on when I start up.

Trans Oil light is only on for a second or so then goes off.

Cliff

[kyle4501]

Brian, that is an interesting sensor. 

Since the contacts are N.O., if the wire to it broke, it would have no way of alerting you there was a problem with the oil level.
If it had N.C. contacts, any break in the circut would alert you to a problem.

Seems it would be better if it alerted you oil loss as well as to a failure of the circut. 
Sometimes ignorance isn't bliss.

Also, with a pressure sensor, you'd need a fast acting gauge so you could see the fluctuations as the level got low.

[David Anderson]

I don't know if Voith makes one or not aren't those guys located in Houston off the Katy freeway.
Does the Voith pickup the temp at the torque converter housing like the Allison most of the time a Allison will show a temp rise when only a gal low or a gal overfilled sorry but I am not much help on the Voith or ZF autos


good luck

Cummins in San Antonio works on Voith.  I've always called the main distributor in York Pa.  I can always get right to a tech on the phone.  They are very helpful.  They just don't have the network like Allison.  

I installed the temp sender on the oil pan.  There are two ports there.  Unfortunately it wouldn't suffice for a fluid level sending unit.

I would think a pressure gauge as close to the pump output as practical would show when the fluid pressure is below a safe operating pressure. I'd definitely put an alarm on that one too - flashing light or buzzer.

However, is this necessary? How often does this happen? I know you got lucky with the timing of your stop relative to the hose blow-out.

I do understand the comfort of having the sensors, but I often wonder if the 'safety' devices lead to increased contempt for proper maintenance - how many of us check our car's oil at every gas fill? I know I seldom check mine - & I should know better! - because I have a 'low oil' light on the dash.

Hard to put a sensor in for every possible thing that could go wrong. . . . Then you have the added PM on the sensors to ensure they are working properly. . . .

Yes, I thought about that.  If I can't do this easily, I'll just replace the fluid lines and be done with it.  Apparently most don't have a fluid level or pressure gauge, so it must not be that important.  If this thread falls down the page with little response then perhaps I'm overreacting.

I just missed the due diligence in the inspection and those hoses are probably original, ie, 25 years old.  

Getting those lines out is going to be a bear of a job.  I may attempt it tomorrow.

David

[blue_goose]

If you have a rapid loss of fluid it won't hurt the transmission.  It will just stop moving.  I lost all of mine one time and was with a friend when he lost a line and stopped.   My wife pushed me 12 miles on a two lane road with the tow car until I found a place to work on the bus.  I had lost the line that goes to the shifter and it just quit pulling.  Fixed the line replaced the fluid and was on the way.  Same with my friend.
Jack

[Len Silva]

I hadn't though about it but that makes sense.  A catastrophic loss of oil will probably not do any harm.  It's the slow loss that might lead to overheating.  A trans temperature gauge is probably the most important.