Rubber boot where clutch goes into tranny.
Same boot ripped and holes in it.
Well I think I found my leak. What caused this? Clutch or just old age and what do I need to do to fix it. Every time I stopped I would leave a big puddle of black oil. Guessing its the old 80/90. Clutch does stick when I let out maybe 3 inches from the top untill I bump it with foot. Any ideas?

 

If your leaving a big puddle of oil I doubt that's where it's coming from. Usually the spot that's leaking is shiny and washed off looking if that makes sense. Just put a little of the oil on your fingers next time and smell it. Gear oil has a very distinctive smell. If it's leaking from the back part of the engine it could be running down from the back of the intake manifold. Very common spot for a 351M/400 to leak from.

 

Also inspect your PCV system and make sure it's working properly. That will keep a slight vacume on the crankcase and help keep leaks down.

 

Thanks for your reply. Just did the manifold intake gasket and freeze plug and all is dry. After driving 800 miles I have not lost any motor oil but my gear oil in the tranny was low and it was full when I left. The area around the boot is soaked its hard to see in the pic. I know its hard to see because I have not had a chance to wash off all the old caking from when I bought it.

 

The boot isn't the source, it is a symptom. Oil causes rubber to swell. You could have a leaking oil pan, but that wouldn't sling the oil around like a rear main would off a flywheel. Is the inside of the bellhousing coated as well? The oil pressure sender or switch would leak down the back, but you probably would have noticed that when doing the intake. Valve cover gaskets can leak back there, especially if the oil drain back passages are restricted.

 

Replaced P.V.C valve also but will ckeck in a.m to double ckeck.

 

Valve cover gaskets were replace just before I left. As of today they were all dry. There is a leak in the oil pan. Bolt front right that is stripped but it is a drip. I searched the whole under side to day and I only found bolt in oil pan and a hole in the side of the tranny where the boot is almost gone. Truck sat for years. So far I've replaced all brakes every thing new. Intake manifold gasket and cleaned ports of carbon build up. Master clyinder, fuel pump. Thermostat, tune up timed and freeze plugs. Pvc valve and replaced edelbrock 600 carb. I even checked all around harmonic balancer to see if that was leaking. Maybe I'm missing something I don't know. I've never been a mechanic just started learning a month ago when I bought this $600 dollar truck.

 

Right now my main concern is the boot and if the clutch could tear up the boot and how to fix the boot. I'm in the desert and worried about dirt BBC getting into the gear oil. Cant be good for it.Having trouble finding a manual I can download on my phone to see how to fix this.

 

Quick and dirty, cut that boot off if you are worried about it. If it isn't there, it can't get into the workings of the clutch.

 

Lol that would work. Wouldn't the gear oil spash out when driving down road and dirt and stuff get in.

 

No, the area inside the bellhousing should have no oil. These pickups use a dry clutch. Some dirt may get in, yes, but trust me, a lot of class 8s (semis) are running around with the inspection plate off the bellhousing with no ill effects. The transmission fluid, whether oil in this case or ATF in the later aluminum case transmissions, is contained in the next part rearward. When you are underneath the vehicle look at the bellhousing and at the rear portion of it you will see two bolts per side. This is the separation line between the bellhousing and the actual transmission.

 

Ok all I know is I can see gear oil is coming from that hole. I even went out put my finger in it and it smells like gear oil. I'm struggling here. In the morning I will put my finger in there and see if its wet. Are t-18s vented maybe a vent is blocked. The fluid is kind of milky so maybe moisture may have gotten in. Montana winters are cold and truck was out side sitting. Gas tank was full of rust.

 

Wouldn't hurt to change the fluid. If there is gear oil in the bellhousing the only place it can come from is the trans. The vent for the gearbox is through the shifter. There is a seal for the input shaft that can be leaking and a gasket for the front bearing retainer. I suppose the top gasket could be leaking as well. All of those, except the fluid change, would require removing the transmission.

 

Ok thank you. Was happy when I found this thought I had escaped have to jack motor to get rear main. This does not sound any easier. Has to be that. Its dry above that point and its dry in front of it. Theres a plate just in front of the area a skid plate or some thing and that's all dry also. I will try and find a car wash and get the oil and all the years of junk of of the bottom so I can see a leak. Should of done it in montana but it took 2 solid weeks of daylight to dark for me to fix it enough to escape montana before the snow hit. Left 1 day before it snowed. Hit the az strip and could stop. Oh well one more fix and I think I got it. Then paint and interior I've got a new truck. And parts are cheap. All in truck, camper and parts so far $1600. So far. Sore back skinned knuckels and all the cussing no charge. Have a great one. Thank you sir.

 

Ok this morning I went out and ran truckvfor 30 minutes got under and could see no leaks except small drip on oil pan where there is a stripped bolt for the pan gasket front of motor driver side. No leak at rear main dust cover or I hour after I shut off. Removed boot from where clutch goes into.side of tranny put my finger inside seemed ok.not full of gear oil. Looked all over all of back of motor could see no leaks. Check pvc valve working. Plenty suction and ball moves freely. Check around fuel pump harmomic balancer nothing. But on trip at fuel pumps I was leaving a puddle of black oil about the size of a dinner plate.I was fueling about every 120 to 140 miles. Wasn't sure how far it would go on tank with camper on. Ran between 55 and 65. No motor oil loss after 800 miles still same level. I don't get it. Has to be something that only leaks under strain. And not enough to affect oil level.