Noticed an oil leak under my truck today. Oil is all over the top of the transmission. Leak seems to be coming from up high somewhere at the back of the motor. Its not a major leak but it is leaking. Any ideas?

Note: I did the Hughes Plenum Fix about a month ago. Could the manifold gaskets not have sealed right at the back of the manifold?

 

My money would be on the manifold gaskets, distributor seal, or rear main. Get under there with a flashlight and dentist mirror and pinpoint it.

 

It's possible it might not have seated. Did you follow the torquing procedure? Check for oil around the intake manifold.

 

Another possibility is the oil pressure sending unit.

 

Just reached around back there and the oil is definitely coming from the manifold on the back side. Not sure if it is coming from the Oil Pressure Sender or from the manifold gaskets. And yes i did follow the correct torquing sequence.

I really dont want to pull that manifold again.

 

id double check the rear main seal as well....its very common for these to start leaking


but since you saidit is comming from the manifold, then re-torque...

When i did my plenum, i retorqued after 200 miles, and yes they backed off a bit, but only a smidge....and thiscould be what happened to you...

Also you know you should retorque the valve covers every 3-5K

 

I will re-torque them down today. As for the rear main seal, if this did go bad could the oil even get onto the top of the trans? Because that is where im seeing most of it.

 

Re-torqued them down and I am still leaking out of the rear manifold area. Looks like I am going to have to pull the manifold, get new gaskets, and try again. I think i knocked the rear crossover gasket out of place when placing the manifold back onto the motor. So now my question is this:

Do you use RTV on the rubber crossover gaskets on the manifold? If so, do you RTV the whole thing or what.

 

just a shade tree move - i'd try a thick coat of rtv along the rear manifold seam. clean it good with brake cleaner and lay it on heavy. it might work and save you a lot of effort.

its recommended to put a nice sized dab of rtv in the corners only. i don't think it would hurt anything to put a very thin coat of rtv on both sides of the front and rear. its tacky and helps hold things in place.

for intake lineup, you can cut the heads off 4 bolts and thread them in as line up studs. drop the intake over them, start the other bolts, then remove the line ups.

 

Just re-did the intake manifold gaskets again today. Only took me 5 hours by myself the second time around. Anyway, after pulling away all of the electrical harness and vacuum lines, I could clearly see the rear crossover gasket right up against the distributor. BAD! Pulled the manifold off again, reset all new gaskets down, and got a good seal this time.

Its amazing how much better the truck runs without a HUGE manifold leak.