So, does anyone know a cost range to have a mechanic change a rear main seal and gasket? Tranny will have to be pulled. This thing is leaking bad. It was only leaking a little, then I went and screwed with it, now it's undriveable. Yay me. Has anyone ever had this done?

Thanks,

Derek

 

How did you screw with the rear main seal? You sure it isn't just the pan gasket?

 

My local Trans shop said $350 to pull trans and replace the rear main seal, and that included the materials like the oil and etc. Yeah pretty good price because he was adding about $50 discount. Forgot to add, my estimate was for the 4x4.

 

Yeah, I didn't actually touch the rear main seal. I think it is just the pan gasket. It's a 4 pc gasket. The rubber half moon part that meets the rear main is what I screwed with.

 

Here you go-

https://www.ford-trucks.com/forums/1...n-inframe.html

 

If it's just the pan gasket, change it. People seem to blame the "rear main seal" way to often in my opinion. I would replace the pan gasket, and if the rear main does leak a little bit, I would try some of that stop leak stuff first. It has chemicals in it that attack the rubber and make it swell up and soften, sometimes stopping the leak.

The pan gasket (lifting the engine up) should be a separate operation from the rear main(taking the tranny out). I don't think you would gain anything by having them both done at once.

 

I appreciate all your comments. Does a 1 pc felpro exist for a 1984 f150 4x4 300-6? My mechanic seems reluctant to do it if he can't use a 1 pc. I'm a contractor and I NEED this truck. I guess I will attempt it myself if he refuses. It doesn't seem hard once you jack the engine....

 

It's a miserable job, that's why he is balking at doing it. Working in a tight dirty area with oil dripping on you continually.

I would look your truck up on Rockauto or Autozone's site and see if there is a one piece gasket available.

If you do attempt it yourself, don't take short cuts and try to clean the pan up without taking it completely out, risking stuff falling inside it. We have had several people do this on here and end up with no or low oil pressure from all the debris getting sucked up in the oil pump pickup screen.

 

Just thought I would update you guys in case you were curious about the result.
Here's what I ended up with: new rear main seal, new oil pan gasket, new clutch.

The main bearing cap was installed backwards by the last owner apparently. The clutch was chattering, thus toast! Also, the main bearings are down to brass! I paid $1159 to get it fixed and find out that the engine is worn out. There's also a hefty groove in the crank.

On the bright side, I'll be getting a new truck next year!

 

So, with all the fixes is the truck "fixed" or just limping? I'm guessing that you didn't do anything about the mains or the crank, but other than the fact that you know the bearings are worn the truck drives ok? Does it have proper power? Does it use oil?

 

Actually I was pretty surprised that he told me all that. It does not use oil. It drives great and has lots of power. I guess I'm just going to inch it along as long as I can. It really seems to run fine.

 

Then I wouldn't worry about it. Do you have an oil pressure gauge? If so, where does the pressure run when the engine gets fully warmed up? And, by the way, the stock gauges aren't known for accuracy so lots of us run aftermarket gauges that actually show what the pressure is in PSI.

 

I will have to get an oil gauge. I go to pick up the truck tomorrow. I will ask him if he checked the pressure. I have noticed that the stock gauges all fluctuate sometimes.

 

Yes, the oil pressure, temp, and fuel gauges are provided their working voltage by the Instrument Voltage Regulator (IVR) and they are notorious for fluctuating voltages, which makes the readings fluctuate. Get an aftermarket unit and tee into the oil pressure port such that both the factory sender and the new gauge are hooked up. Dad's 351M with 145,000 miles on it goes to 70 PSI when the engine is cold, but after about 20 minutes of driving the pressure gets down to about 40 PSI on the road. And, it'll drop to 20 idling. But, that's adequate pressure so I'm not worried.

 

Thanks for the info. The truck doesn't "act funny" in any way, so I never even considered engine wear as a possible problem. My mechanic kind of hurt my feelings when he told me the engine was worn out. I love the 300-6. Hopefully it will hold out a while longer.