Oil leak questions.
 

Last week as I was walking up to my truck, I noticed what looked like a leak under the truck so I stopped to look and I found engine oil dripping from the rear of the engine by the torque converter, oil was dripping off the transmission and rear mount, it leaves a good sized puddle when I stop for more than about 20 minuets.

Looking from under the wheelwells I can see the entire side of the block and I know it is not the side cover it looks to be comming from the back of the engine.

I had replaced the rear main seal about 2 years ago so it should not be from that, where else could oil be comming from?

Are there any galley plugs or cam plugs on the back of the engine block that could leak?

Is it possible for the main seal to leak so soon?

Oh BTW the back of the head is not leaking either.

Thanks for your help in advance.
Jim

From my IBM field engineering training days..... Toughest principle to teach.

1. You walk up to a running machine.
2. You do something to it.
3. It now does not run.
4. The fault is in what you did.

It is possible to make an error when installing a seal.

<edit> Just noticed the rear seal is 2 years old. Principle still applies in general, though, and is worth keeping in mind as it is typical human nature to be in denial when the dung hits the ventilator.

Combining Jim and John's posts[laugh]
Why don't the British build computers?[laugh]

Because Lucas makes their electronics?

Honestly though there isn't much back there to leak oil except for the seal. Maybe the oil pan? I would clean everything off real good, put some dye in the oil and run it for awhile. Use a black light to look for the source. Exhaust all possibilities externally before pulling the transmission.

Because they can't figure out how to make them leak oil.

Makes me wonder if there was some British influence in the design of IBM,s 1403 chain printers. They had a hydraulic carriage control unit that held a gallon of hydraulic oil. One on our maintenance leaked enough oil onto the main wiring harness, which was carrying 10 amp or so hammer firing pulses, that it caught fire.

LOL[laugh]

I would not be questioning my work if I did something wrong or not, because I would also have about 100 pictures of the operation to go back and look at.

The tech who replaced my transmission is the one that replaced the seal when he had it out for repair.

I gave him the seal and a copy of the FSM and told him this has to be followed or it could leak. (no oil or fingerprints on the surface) so that is why I was wondering if there was anything else back there that could cause the leak.

Jim

I can not think of anything else that could leak back there either. If the housing that holds the rear main seal was removed to replace the seal and not recentered on the crank when it was replaced the seal tends to wear on one side and then leak, don't ask me how I know that. Hope its something easier than the rear main. Good luck.

The back of the engine has the crank oil seal, rear main housing gasket, oil pan and the rear cam plug. There may... infact give me a minute to go out to the garage... I'll edit this post

Here is the back of the motor. It's an old junk block but as you can see on the left side there is a big hole. That is for the cam. The big plug at the top at the back as you know is the rear freeze plug. Just above and to the right of the cam plug, next to the bolt hole is another oil galley plug.

Based on your symptoms I'm thinking it's not either of those. If either came loose you'd have an exxon sized leak while the motor is running. Sad to say, but I'm inclined to think it's that rear main again.

Attachment 50973

I have a 91 in yard that I'm doing some work on for a friend with a rear main leak. I did my 93 last year, and I did my previous 91 @250K, so I'm inclined to think it's your main again also.

Unfortunately,
I also think the rear main seal is leaking again, like I said, I didn't replace it, my transmission guy did and for all I know he could have put it in incorrectly.

It is leaking from behind the converter cover and seems to be on the pressure side of the system, it DRIPS oil at about 1 healthy drip per second.

Ok I just went outside and removed the cover and tried see where it is coming from, the inside of the bell housing is wet with oil and it puddles at the bottom side, then it looks like the ring gear slings the oil everywhere. There is also oil at the rear of the pan, I checked the bolts and they are all tight.

Just out of curiosity, is there a repair sleeve available for this seal?

How difficult is it to remove the A727 from a D-350 like mine?

Can it be done with one helper 4) 8-ton jackstands a floor jack and a rented transmission jack in my driveway?

I have replaced clutch on a W-250's but never a D-350.
I also found out that you can still burn your fingers on the hot torque converter 2 hours after the truck was shut off. Ouch.

Jim

You can do the job in your drive way. It will make a mess though as when you disconnect the cooler lines the torque converter continues to drain out the front fitting. Pulling the dipstick tube while the engine is off will also result in a lot of fluid exiting the transmission.

If you want to do this yourself I suggest pulling the trans pan and draining the fluid first. Then loosen the valve body bolts and pry it down just a little. This will allow the converter to drain down so you won't have as much continual leakage.

I would bet the RMS as well. I was going to mention all of the things that Rick did above but I would start with the RMS.

I've purchased a front seal kit with a wear sleeve. So there must be kits available for a RMS with a wear sleeve. I'm looking for the numbers at the moment.

Position 6: Oil seal. P/N: 3921265
Position 8: Wear sleeve. P/N: 3906081

https://quickserve.cummins.com/rtgra...fh900gt_lg.png https://quickserve.cummins.com/rtgra...ks900gb_lg.png

The 2 part numbers are more than likely not associated. However, if you call Cummins and give the number for the RMS, ask for the kit with the wear sleeve. They should be able to find it based on that number. If, somehow, that doesn't work, give them the number for the wear sleeve and ask for the associated seal.

Cummins Rear Main Seal Speedy Wear Sleeve 3926126

Cheaper here:

DS-3926126 | Cummins Rear Crankshaft Oil Seal Kit | B | C Series