beebeeri000

hey guys i picked up a '79 sr5 a few weeks ago and i was looking at under it and it has oil dripping from the trans. it only leaks when it drives and its a slow seep where i can find exactly where its coming from because the whole bottom will be covered with a thin layer of oil. at first i thought it might be the rear main seal but there's oil a bit further back than the bellhousing and my engine oil level hasn't gone down. i'll post some pics if anyone can help me out with what it might be.

zombie_stomp

Have you seen how your oil pan gasket is doing? I've had 2 1st gen toyotas so far, and both times I ended up doing the timing chain, and when I did, I had to do the oil pan gasket. Both had similar problems.

I wondered and feared about the possibility that is was the rear main seal. Both times I ended up resealing the oil pan using RTV silicone gasket maker, and cleaned everything up really well, mostly during the oil pan gasket replacement process. I cleaned it inside and out, and when I was about to put the oil pan back in, I made sure the block mating surface was free of drips, all the way down to sticking a rag in one certain area until just before I put the pan back on.

After the oil pan reseal, there was never a leak again from anywhere except maybe a slight weep at the transmission output shaft.

I did try a cork gasket on the oil pan on the second one, but I must have overtightened it, as it failed. The RTV on the oil pan gasket has not let me down yet.

*Edit: smell the oil that is leaking and see if it is engine oil or gear oil. Gear oil smells different as you may knw, and will feel thicker of course. You probably already knew that, just want to make sure we know what is actually leaking.

Both times, I was replacing the timing chain, so the front oil pump seal was included in the kit and replaced. That's really easy to get to so can be replaced just about any time. If you have over 100k, might want to do the whole timing chain and oil pump and oil pan gaskets. It makes for a rough 3 day weekend of work, but well worth it.

It can be really hard to nail oil leaks if it's been saturated in oil for a long time. My current 4x4 had a lot of oil from the valve cover gasket all over everything. It took me a weekend of scrubbing just to get it clean enough to replace it.

I found that the easier to get to gaskets cause more oil leaks on the engine than the rear main seal ever did. Once I stopped the oil pan and valve cover leaks while doing the timing chain, cleaning meticulously as I went, all leaking stopped completely.

If you have an engine over 300k, it may just be time to rebuild. You're going to have some dirty nights under the truck either way though, so it's time to suit up.