The '88 has a leak......

[Dirsuper]

I am baffled. I pull in the shop the other day and notice about 20 minutes later that there is a decent puddle of some mysterious dark fluid under the Blazer. I can not tell if it is transmission (have not dropped that pan in at least 10 years so it's a bit......'seasoned') fluid or oil. So I check them both. Oil is fine, tranny is not even showing on the dipstick (running, warm). I added some fluid and ran it up and down about a mile long hill a few times, pull back in the shop and see the pic below. It damn sure looks like it is seeping out of the gasket mating surface for the tranny pan, but maybe I just don't want it to be a rear main seal.......any thoughts? When I put it on my fingers and walk out in the sun it almost looks like a mixture of oil and tranny fluid....it does not smell like tranny fluid, but it's so old, I would expect it to be a bit off.

 

[rampage]

Can’t see the pic since I’m not a member, but clean off the pan where you suspect the leak then take it for a short drive. Should be able to tell where it’s coming from. But it sounds like you’re overdue for a tranny fluid/filter change. Add a new gasket at the same time and check the pan for trueness. Then tighten the bolts to 14 in/lbs (IIRC) and check for leaks for the next couple hundred miles.

 

[bp71k5]

Might be the pan, but looks a little wet up above too so you might degreaser the area with some purple power, dry it off, then take a shorter drive and see for sure. Sometimes the radiator fans can blow a leak up front pretty far back.

 

[obijuank5]

Take off the converter cover and inspect the front pump seal on the trans.

 

[Dirsuper]

Thanks guys. Yeah, I cleaned it and drove it around a bit....still can't tell. I'm gonna change the fluid/filter in the tranny, and while I am at it, I'll remove the converter cover so I can see if it's coming from the front of the tranny or the rear main. All around the valve covers is dry (I've never taken them off and I've had this one for about 15 years). Under the intake manifold is dry......I hope it's not a rear main........My '72 is moving so damn slow as it is (life/job getting in the way), that I'd hate to have to change the damn rear main in the '88. My daughter is going to start driving the '88 to High School in about 6 months so I need it to be dialed in.

 

[diesel4me]

ATF should be red or pink,if its black looking its likely to be motor oil..
Maybe the transmission was low on fluid for other reasons,hopefully..

When you change the oil ,look close at the oil filter mounting area,and any oil cooler hoses and check for leaks..oil cooler hoses on later trucks like to fail at the crimped "shell" or at the aluminum tubing..