TH400 Transmission using Fluid...but where is it going???
 

I just recently purchased a 72C10. I believe it has the TH400 Transmission. When I pulled away from the place of purchase I added a quart of transmission fluid. I drove it at most 10 miles and it has been parked for 2 weeks while I tinker with it. Tonight I had to put in another quart to get the fluid to the correct level. There are no visual signs of leaks on my garage floor. Is this leaking around the transmission and then collecting dirt or what?

Re: TH400 Transmission using Fluid...but where is it going???
 

wonder if the torque converter is full??...has the tranny been recently rebuilt???

Re: TH400 Transmission using Fluid...but where is it going???
 

could the vaccum modulator be the culprit? when they go bad the diaphram leaks and fluid is sucked into the intake manifold then burned by the engine. pull the vac. hose off see if it is wet in there or really soft and squishy. jim

Re: TH400 Transmission using Fluid...but where is it going???
 

Possibly leaking from the transmission cooler into the cooling system?

Re: TH400 Transmission using Fluid...but where is it going???
 

The tranny has not been rebuilt for a long time. I will check the vacuum lines and see if that is it. There seems to be a lot of oil soaked dirt all around the transmission that could be soaking it up. Where would leaks form on a transmission except for around the pan?

Re: TH400 Transmission using Fluid...but where is it going???
 

front seal ,rear seal ,around the dipstick[thats a bigge] speedo housing extension housing and of course the overflow in the top [breather]

Re: TH400 Transmission using Fluid...but where is it going???
 

Check the vaccuum modulator on the pass side probably diaphram busted sucking the fluid into the motor .It does it so slow it doesnt smoke but sucks the fluid out of the trans

Re: TH400 Transmission using Fluid...but where is it going???
 

Mine leaks out the tach cable, like a sieve mind you.

Re: TH400 Transmission using Fluid...but where is it going???
 

Just putting this out there,...you did check the fluid level on hot idle? it may not really have needed the top up.

Re: TH400 Transmission using Fluid...but where is it going???
 

That's where I would start too.

Re: TH400 Transmission using Fluid...but where is it going???
 

I would check your radiator. I lost one 700R4 this way as stated above, the heat exchanger can go and mix the fluid, you keep pouring in tranny fluid and it disappears. If it's your heat exchanger your antifreeze/coolant will look like a brown/pinkish milkshake.

Re: TH400 Transmission using Fluid...but where is it going???
 

this is also my first question.

the truck is running and warmed up when you are checking the fluid, right?
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Re: TH400 Transmission using Fluid...but where is it going???
 

The truck is definately warmed up and running. I will check the heat coolant when I get back and also look at the other things you guys mentioned. Thanks for all the help!