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Turbo 400: transmission fluid coming out overflow

B

Bohemian

Guest
This is a weird one, truck has been sitting 6 months while I was working on it, nothing related to transmission...

Transmission is well maintained and was fine when I parked it, started it up today and was letting it idle for like 20 minutes to get the electric fans to kick on, get everything circulating again, etc...

About the time the electric fans kicked on, it started spewing atf out the overflow tube on top of tranny.

No way it was over filled.

Scratching my head on this one, I've seen the pan gasket go bad from sitting, but never seen this shit...

anybody got any idea's?

thanks in advance.
 
Sitting inside or outside?
Any chance rainwater got into the dipstick ?

Other than moisture boiling out of the fluid, I got nothing...:dunno:
 
wasted wages said:
Sitting inside or outside?
Any chance rainwater got into the dipstick ?

Other than moisture boiling out of the fluid, I got nothing...:dunno:
Click to expand...

It's been outside in my driveway, no chance of rain getting into the dipstick and we've not had a drop of rain in the last 6 months.

All I did was start it, and let it idle in park for about 20 minutes before it started puking out the vent and I shut it down.
 
When the fluid puked out, was it clean or like a pink milkshake?

I've had transmissions puke before from overheating and from taking on water after being stuck overnight in a creek.. water will make the fluid look milky...

it's hard to believe that it overheated idling for 20 minutes unless it had a bunch of water mixed in it..
Only other thing I can think of is if you had the radiator out of it while you did the other work, could a line or the cooler tank gotten plugged somehow ?
If the cooler line gets deadheaded by a clog or something blocking the cooler tank, the fluid from the pump and T/C may have gotten hot due to no flow....
 
wasted wages said:
When the fluid puked out, was it clean or like a pink milkshake?

I've had transmissions puke before from overheating and from taking on water after being stuck overnight in a creek.. water will make the fluid look milky...

it's hard to believe that it overheated idling for 20 minutes unless it had a bunch of water mixed in it..
Only other thing I can think of is if you had the radiator out of it while you did the other work, could a line or the cooler tank gotten plugged somehow ?
If the cooler line gets deadheaded by a clog or something blocking the cooler tank, the fluid from the pump and T/C may have gotten hot due to no flow....
Click to expand...

No water in atf, did not touch engine, transmission, radiator, cooler lines.

It may be something causing it to overheat, but this tranny has never puked out the overflow.

I'll try blowing out the cooler lines, but idk how this thing could get plugged up from sitting. It's always been serviced regularly, by myself filter, fluid and pan gasket once a year and it's lucky to get 5 thousand miles a year on it, it's a hunting truck, 82 K5.
 
I'd dump the fluid and check it out. The two reasons I think of that it would do that is overheating or overfilling. And overheating shouldn't happen idling in the driveway. Add you haven't added any fluid, if your radiator suddenly started leaking coolant into the trans cooler portion then that could do it but the fluid would show it.

Are you sure it's coming out of the overflow and not somewhere else?
 
folkenheath said:
I'd dump the fluid and check it out. The two reasons I think of that it would do that is overheating or overfilling. And overheating shouldn't happen idling in the driveway. Add you haven't added any fluid, if your radiator suddenly started leaking coolant into the trans cooler portion then that could do it but the fluid would show it.

Are you sure it's coming out of the overflow and not somewhere else?
Click to expand...

It's coming out the overflow tube on top of case, no doubt, I crawled under the truck.

It's not overfilled and there's no water in the atf.

It was 100 degrees outside yesterday, so Something could have got hot pretty quick, and the fluid started spewing about the same time the electric fans kicked on, I think the sending unit that kicks them on is a 195 if I remember right. It's a big ass ron davis racing radiator with dual electric fans it should never get hot.

Like I said nothing related has changed and it's never done this before.

I'll blow the lines out today and try it again, if it does it again I'll do the fluid, pan gasket and filter drill again. If it does it after that I guess next step is the transmission shop.
 
another question, is the trans modified in any way ? shift kit ? reverse valve body ?

sometimes internal leaks and/ or stuck valves, plate gaskets can do weird things...cause clutch packs to hang, drag, bands to apply....
 
Greg Ducato said:
I bet some critter decided that your vent line would be a fine place to build a home, and when the pressure built up it pushed it and the pent up fluid out of the vent. We see it happen all the time with vehicles that sit for a while and more so if they have locking dipsticks .
Click to expand...

Almost burnt a customers car to the ground 10 or so years ago because of this exact issue. Had a turbo 350 in a Supra. We swapped a 400 in and I took it for a test ride. Got back and went to check the hot level. Pulled the dipstick and it started shooting out and all over the exhaust. Luckily I closed the hood and minimized the damage with a extinguisher. Dirt dobber built a home in the vent. Good times.
 
Ever since I found my vent plugged with mud during a rebuild, I now drill and tap the case with a 1/8" pipe tap. Then use a 1/8 mpt x 1/4 male flare fitting, #4 pushlock fitting and hose ran high up into the engine compartment and put a small vented filter on the end... I do the same for my transfer cases and axle vents..

It's cheap insurance.

Something to remember is that a hot transmission or t-case, axle etc, dunked into a cold river, stream or liquid mud will immediately cause the case to go into a vacuum and suck water or mud inside thru the vent if under the water level... just simple physics !
 
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