where is my transmission fluid going?

95 blazer, had transmission rebuilt, transmission fluid dissapearing.. not leaking on ground, no fluid around transmission .. no fluid in coolant .. may be leaking into oil.. is this possiable????

4wd? if yes...could be going in the transfer case. to check, remove the transfer case fill plug, the fluid level should be level with the bottom of the hole. If excessive amounts of fluid come out when the plug is removed, you found your problem.

Yip, check to see if the transfer case fluid come out when you remove the top fill plug.

If fluid comes out, you know where it is going.

The transfer case fluid should only be up to the fill hole only.

4wd? if yes...could be going in the transfer case. to check, remove the transfer case fill plug, the fluid level should be level with the bottom of the hole. If excessive amounts of fluid come out when the plug is removed, you found your problem.


yes it is 4wd,,.... 4wd had not worked for a couple of years now.. never thought of looking there... going back into shop tomorrow.. under warrenty .. thanks for the input... :)

Good luck and let us know what happens.

After you get that squared away, come back and we'll help you fix your 4wd.

Mine loses fluid thru a vacuum line that is connected to the top back of the tranny . I think it is a vacuum switch that controls the front differential engagement . I get fluid in the line where it connects to the intake manifold .

Good luck and let us know what happens.



well ...aamco can not find the leak.. not going into the transfer case either... well I guess I am lost now... time to trade it in... :( I guess I will continue to drive around with a case of tranny fluid in the back..

Posted by Rmbodie - 02-25-2005 at 02:13 AM
Mine loses fluid thru a vacuum line that is connected to the top back of the tranny . I think it is a vacuum switch that controls the front differential engagement . I get fluid in the line where it connects to the intake manifold .

i've heard of this before, something about the fluid being sucked through the vacuum lines and shot in a bunch of places in the engine, casing some other problems. has anyone else heard of this?

Posted by Rmbodie - 02-25-2005 at 02:13 AM
Mine loses fluid thru a vacuum line that is connected to the top back of the tranny . I think it is a vacuum switch that controls the front differential engagement . I get fluid in the line where it connects to the intake manifold .

i've heard of this before, something about the fluid being sucked through the vacuum lines and shot in a bunch of places in the engine, casing some other problems. has anyone else heard of this?
Man you are really making me exercise the ol gray matter now. I have heard of this before. IF IF IF IF my memory serves me correctly, some vehicles used to have a "Modulator"???. Anyway, it was a bulb looking thing on a steel tube that ran from the intake manifold to the tranny. It kinda looked like a fuel filter, sort of. I don't know if it had a diaphram inside of it but, if this "Modulator" went bad you could loose tranny fluid into your engine.

Now before anyone sticks a hose in my nose, I AM NOT SURE IF THIS APPLIES TO BLAZERS OR ANY VEHICLE ANY MORE. I am just saying that I have heard of this and to check you simply remove the tube on the engine side of the modulator, if there is tranny fluid present, it was bad, the fix was to replace the modulator. :icon16:

Right after I bought my 83 s10-blazer 4wd in 2000, i wanted to figure out 4wd system to get it working. the vacuum lines to switch had been sucking tranny fluid up and fluid was even in vac lines in dash. this intervered with proper vac line functioning. disconnected a line at a time at both ends and blew fluid out. same with vac ball. changed the plastic vac switch on top of transfer case that the 2 vac lines connect to. this may have been caused by faulty switch or previous owner connecting vac lines wrong, like engine side vac line to 3rd vent nibble of switch. i had garage do it. i think the switch is atop the transfer case, not the tranny. could be wrong. same fluid in each anyway.

your engine intake is likely where you fluid going and gettting burned off.

i suggest you clear all lines and ball and get picture of which line goes where on switch and change the switch to be safe, it's cheap.

what i think of is the swich on top of the t case and what happens is the rear seal of your trany leaks atf into the t case and it fills up. and eventualy the swich wares out beacuse the t case is so over full then the swich starts to suck up the atf i would take the fill plug off the t case and if alot of atf runs out its your rear seal if not good luck