Pan Gasket

Oh man, there's so much grime in there it's hard to tell the source from those pics. Since there's a ton of grime up above the gasket as well it could be the valve covers, or maybe a bad front main seal that has blown crap back all over from the fan, or timing cover... really anywhere. Clean the whole area up and see what gets nasty first.

As for the rear end, that looks like the pinion flange seal, not one that's simple to replace without the proper tools/procedure or you'll risk ruining the gears if you don't set the preload properly.

Zeal69 said:

OK, I'll check the front main seal as well as the timing cover, it is not the valve covers as the gaskets have been replaced. Since I might have to potentially change the pinion flang I'm thinking of changing the rear gears as well any recommendations 3.55 vs. 3.73?

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The gear choice is up to you, depends on a lot of things. What mods do you have? How do you use the car? Auto or T5?

Personally, for an AOD car, especially an 86 that's down 25HP from the 87-93 cars to begin with, if you are not planning on doing any long highway trips with it, and this is just a spare to take out and cruise locally once in awhile, I'd suggest you go straight to a 4.10 gear and be done.

3.73s would also be ok, but with that stock 86 engine, especially if you have no plans to modify it, go 4.10s for a noticeable seat of the pants difference.

I'm debating this right now with my T5 87 GT. I'm going with a 3.55 or 3.73 gear in it. The engine is stock and at this time I'm not sure if I'm going to do any major modifications other than possibly a trick flow top end kit and possibly a 347 stroker. That would be years down the line, if at all. I'm not sure yet.

I've had several 3.73 geared T5 stangs and they are a blast to drive because 1st gear is low with the 73s. I'm leaning towards the 55s this time due to the possible future mods. But man I love the pull I remember in 1st and 2nd with those 73s so I'm not sure just yet.

My car has the terrible 2.73s in it now (which pretty much makes 5th gear useless for the type of driving I do with it) so either of those will be a huge improvement for my car.

Just my .02. Good luck