2F newbie oil leak question

[SwissEd]

Hi,
Just got my 1980 Fj40 and clutch was replaced. I have a leak at the rear of the oil pan- truck had been sitting for several weeks so thought seals might be dry. Have since driven a couple of hours and get a drip at rear most point of pan. I read about oil relief valve and not sure how this works or if this could be the problem. Any suggestions on how to isolate this problem? I thought it was likely gasket issue and oil simply draining (dripping) at rear of pan, but this might be wrong. It is originally CA truck (with all those emissions hoses) and now in Switz. Finally, just had all brakes replaced, including calipers (cracked), rotors and rear cylinders, springs, pads, shoes S/S lines. Truck has pull left on braking. I have only 50 miles on new brakes- could this be a 'new bedding' problem and I should ignore and keep driving for a while? I lifted rear of truck and both rear wheels turn freely- I have not yet done front to see if calipers dragging or wheel bearing too tight.
Any suggestions much appreciated and thanks guys,
Ed

 

[lc69hunter]

might be rear engine seal

 

[D'Animal]

Is the oil coming down onto the oil pan or towards the rear of the clutch inspection cover?

If it is coming from the rear area, your seal may be blown between the transmission and t-case. The t-case will pump fluid to the transmission ad litterally overfill it. The oil can push out the front seal of the trasmission.

A quick way to check if this is your problem is to check the oil level in your t-case and tranny. if the tranny is overfull and the t-case is low, this is your problem. Install the oil bypass kit and fix it the next time you have it out.

 

[Dusty 66]

A couple things you can check before you go through the trouble of changing the rear oil seal,The rear main seal gets blame for most oil leaks
One pull the Clutch Inspection cover and determine if the oil is coming from inside the cover for one, if it is the rear seal the engine side inside the bell housing will be obvious leak.
If is at the transmission side Its most likely the front transmission seal witch is a prone to leak in older trucks.
If no oil inside the clutch inspection cover your leak is coming from another source

The rear Valve cover is a likely Culprit, for what most people assume is Rear main oil leaks,Very common to have an oil leak and appear as a leak at the rear of the engine.
also check the bolts and gasket at the Mechanical fuel pump for oil leaks very prone to oil leakage too. and you could check the front oil seal as well,
all your oil leaks tend to collect at the low point.

As for brake problems your just going to have start at the wheel cylinders/ calipers and work back one may be frozen, also check the proportioner valve below the Master,
Good luck Joe C

 

[FJ40zen]

Here is a picture of an oil pan gasket leaking at the rear of the engine. Remove the clutch inspection plate. Notice the oil drip forming in the picture? If yours is leaking like this and it is the only place that is leaking there, all you need to do is drain the oil, drop the pan, scrape the old gasket off and install a new gasket. You might want to dab a little Permatex red in the gasket groove of the bearing caps where they meet the bottom of the block, front and rear to get a good gasket seal at those points.

 

[Cruiserdrew]

9 times out of 10 it will be the oil pan gasket. Lots of other stuff can leak, like the rear main, the cam plug etc, but it's usually the oil pan gasket. Before you get excited about the expensive stuff, replace the gasket first. If that doesn't solve your leak, the look at the expensive stuff.

 

[Blueegg]

Is the oil coming down onto the oil pan or towards the rear of the clutch inspection cover?

If it is coming from the rear area, your seal may be blown between the transmission and t-case. The t-case will pump fluid to the transmission ad litterally overfill it. The oil can push out the front seal of the trasmission.

A quick way to check if this is your problem is to check the oil level in your t-case and tranny. if the tranny is overfull and the t-case is low, this is your problem. Install the oil bypass kit and fix it the next time you have it out.

This is my leak problem. It leaks at the rear, the tranny overfills and the t-case runs low!
My approch has been to drain oil out of the tranny and add to the T-case.

Is this something I need to correct soon?

 

[Blueegg]

A search for prior threads was very productive.

An oil bypass will be on my rig soon.

 

[SwissEd]

Thanks so much for all your input- THIS IS A GREAT RESOURCE for all us newcomers! I am much indebted--- will start the investigation. Odd thing is Toyota did replace the clutch 2 weeks ago (and when it went in it was not leaking at the pan (not on my garage floor anyway). The seal between transfer and tranny was shot and that was a leak. Could the replacement of the clutch be in any way connected to leak that is manifested at right where the drain plug is? I had truck up on lift this morning with them and thought it could be a) oil pan gasket; b) small gasket around plug: c) something else. Many thanks, Ed

 

[ibejamie]

Hi Ed,
Did you change the oil recently? With synthetic oil? I have the same problem- bought an 83 - NO LEAKS... changed the oil- put in synthetic blend... and now I have a leak. It was only after reading here I learned that that will happen with older trucks / cars. Better off using the straight motor oil and not 'upgrading'... the gunk seems to keep things together sometimes- just my .02

Good luck and when you do find out what the leak is post it up.

Jamie.

 

[SwissEd]

Jamie,
Yes you are correct that semi-synthetic 10-40 was put in some months ago during the Swiss inspection process. The truck sat for months waiting to sort out stuff and no leak other than gasket between tranny and transfer. That has been replaced (clutch as well) and no leak there anymore, however I also had another thought. I heard that if the truck is not driven often the seals can dry out and leak. Well I drove it for several hours this weekend and the leak persist. Overnight I have a small amount of drips that say is about 3 inch diameter so it is not just a drop or so. Could 10-40 semi-synthetic on truck with 60k miles be too thin? I don't plan on driving here in the winter, it is a 'dry weather' truck.

thanks,
Ed

 

[D'Animal]

Welcome to the world of synthetic oil.

You can have a tightly sealed Land Cruiser. Convert everything over to Synthetic and you will be chasing leaks.

I think the molecules are smaller and they can fit between the seals and shafts, etc.

Yes, I'm scared to run synthetic in my rigs.

 

[Dusty 66]

Welcome to the world of synthetic oil.

You can have a tightly sealed Land Cruiser. Convert everything over to Synthetic and you will be chasing leaks.

I think the molecules are smaller and they can fit between the seals and shafts, etc.

Yes, I'm scared to run synthetic in my rigs.

Yep I used it once in my FZJ80 went through a Quart every 200 miles no visible leaks too

A month later I went back to using regular Oil in problem corrected.