Low transmission fluid question 4r100

[don1911]

I recently noticed their was no fluid on the dipstick of my transmission on my 2000 Excursion 4x4 7.3. It turned out it was a quart low so I added a quart of o Reilly's mercon v synthetic to it. My dad had a 7.3 with a 4r100 and it was never low? Opinions on why it was low was it cheap fluid that burned up? Or what?

 

[Lubener]

You have a leak somewhere. ATF doesn't get consumed.

 

[don1911]

Thanks. I will check for leaks

 

[SwampSurvivor]

Pump seal leaking?

 

[supton]

Output seal has a weep?

Was it full last week, last year, or is this the first time it's been checked?

 

[Terry Hennessy]

Thanks. I will check for leaks

If trans has oil cooler in front of radiator, start there? Replaced my old hoses (1999 in 2017) that were getting stiff when I found leak, but believe leak may have been a loose screw clamp. Ended with two narrow screw clamps at every hose end for safety.

 

[don1911]

That's a great idea

 

[Lubener]

Most of the time it's the pan gasket. Either snug the bolts or do a pan drop. However, we are all guessing. We won't know till you have someone look at it or you slide under and take a look for yourself.

 

[thastinger]

You have a transmission cooler in front of your radiator and your transmission line runs through the radiator.

 

[crashz]

That trans had an issue as it got older that would allow the front seal to leak under high load/high heat. For some reason would be worse in reverse. My father's 1995 F350 did that when we plowed after it got older. The fix was obviously the front seal replacement but I can't remember if the TC hub got scored.

 

[don1911]

Pump seal leaking?

No idea but I am going to put it into a shop

 

[don1911]

Everyone has given me great ideas thanks to all of you

 

[don1911]

My friend Dahlia who is a retired mechanic put a bottle of transmission stop leak in on a road trip. It fixed the problem. Unfortunately I don't know what brand she used but whatever she did it is not leaking anymore

 

[BC1]

That transmission had an issue as it got older that would allow the front seal to leak under high load/high heat. For some reason would be worse in reverse. My father's 1995 F350 did that when we plowed after it got older. The fix was obviously the front seal replacement but I can't remember if the TC hub got scored.

This is my experience as well. Mine leaks every summer pulling my enclosed gooseneck, but only then. Never during cool weather or towing my open trailer. I add about a quart each year. No chance I am going to drop that heavy transmission for that.