MTFCA Forum

I have a 1921 touring that I have been driving for 6 years with no trouble.> As part of my routine service in the spring on checking the rear end oil I found about 2-3 cups of oil coming out of the fill hole. I checked it again today(after about 250 miles) and found about 1 cup coming out. I realize that the oil is leaking past the 4th main into the rear end,
I have ruskell rear end that i keep in low and only drive it on short trips in town. My question is can i keep driving as is without causing damage to the rear end. I am reluctent to pull the engine to replace the rear main. Is there any easy fix other pulling the engine?

Question... When you're doing an oil change, how much oil do you put in.... Using a pressurized grease gun to fill the universal joint area is advantageous and will help to slow down engine oil from traveling down into the differential..... What gear oil are you using in the differential?.. 600 weight?, or the modern equivalent weight 140-170 (disregard numbers on modern, I'm just guessing, I use the 600. )

Your rux should be running 90wt. Motor oil is too thin. You put your rear end @ risk with the lighter lube AND using the rux as your primary driving.
You are putting a 3-4,000 $ piece @ risk. There is a lot of wear & pressures inside that diff in under-drive.
If you normally drive this slow to need the rux reduction all the time, you should have set it up with a lower gear set.
Fix the problem.
Do you keep the crankcase oil level to high? Keep it between the 2 petcocks.
You can pull the axle OR the engine.
However, why did the 4th main fail?? misaligned transmission or bent pan?
Maybe better to pull the motor & fix the ROOT cause.
Not what you wanted to hear.

I can give you some tips to limit/slow the oil leakage.
1) keep the oil level between the 2 petcocks.
2) dont run thin oil. run straight 30wt.
3) The transmission screen focuses A LOT of excess oil right to the 4th main. Removing it may be an option.
4) the 4th main can be pulled & turned 180 degrees to put the oil hole on the bottom side.
5) keep the U-joint packed with heavy grease.
Maybe these "hacks" can get you thru this season, but you still need to fix correctly.

P.S. pull the wheels & check the grease seals for leakage & wet brake shoes.

Motor oil can also migrate down past the soft plug in the driven plate.

Steve that’s a great point often overlooked. I’m not saying I’ve done this but a similar situation was happening on a friends T. His temporary solution was to loosen the rear axle to drop the driveshaft/tube out to inspect. He found 4th main was still decent, he used his shop light to look inside the tail shaft, after spraying brake cleaner in it he saw oil leaking out. Not wanting to pull the engine right away he took a large rubber cork formed it and drove it into the hole. That solved the issue. The temporary fix is still working a few years later. Ha
PS just so y’all know he got the cork at Lowe’s in their specialty section where you find odd automotive & furniture hardware, they even have knurled brass thumb nuts in various sizes.
Best John

JTT3 wrote: ↑

Wed Jul 17, 2024 1:02 pm

Steve that’s a great point often overlooked. I’m not saying I’ve done this but a similar situation was happening on a friends T. His temporary solution was to loosen the rear axle to drop the driveshaft/tube out to inspect. He found 4th main was still decent, he used his shop light to look inside the tail shaft, after spraying brake cleaner in it he saw oil leaking out. Not wanting to pull the engine right away he took a large rubber cork formed it and drove it into the hole. That solved the issue. The temporary fix is still working a few years later. Ha

Best John

Thats a great fix for a missing steel plug. I am going to remember that if the situation comes up.
However, in this case, getting progressively worse,(a missing plug wouldnt get worse quickly over time) it wouldnt fix OP's problem.

If it didn't leak for the first 6 years it's probaly not the plug missing it the output shaft. I would suspect the 4th main.Pulling the rear out is the
next step either way.
Craig.

Get a nice bottle of champagne. Save the cork. Put it in a lathe so it is a little oversize and shove it up the a__ of that transmission. That should seal it for a season. If you still dont have time to pull the engine next year to install a plug, buy another bottle of champagne. You might need a long corkscrew to get the old cork out.

Rear end oil/grease is thick so it stays in the pumpkin. Too thin and it will work its’ way down the shafts and out through the ends, coating the brake drums and creating a dangerously slick and messy situation. Find the problem and correct it, then change out the rear end for new 600w grease. Fourth main probably needs to be rebabbited and drive plate shaft machined to fit.

Do you know if you have plug?

I do not use the concave plug in the output shaft. They can be cocked, and subsequently leak. Instead I use a cup type plug. 1" diameter, driven in square to the bore. They do not shift.

Allan from down under.

I would not flip ball cap upside down.

I knew a guy who drilled a hole in the torque tube to drain oil as it traveled down toward the rear end.

Never seen a hole in the drive shaft, but my neighbors 1920 touring car has a hole on both sides of the rear axle tubes out by the ends on the
bottom. If you jack up one side of the rear end to high it will drip out on the ground.
Craig.

speedytinc wrote: ↑

Wed Jul 17, 2024 1:22 pm

JTT3 wrote: ↑

Wed Jul 17, 2024 1:02 pm

Steve that’s a great point often overlooked. I’m not saying I’ve done this but a similar situation was happening on a friends T. His temporary solution was to loosen the rear axle to drop the driveshaft/tube out to inspect. He found 4th main was still decent, he used his shop light to look inside the tail shaft, after spraying brake cleaner in it he saw oil leaking out. Not wanting to pull the engine right away he took a large rubber cork formed it and drove it into the hole. That solved the issue. The temporary fix is still working a few years later. Ha

Best John

Thats a great fix for a missing steel plug. I am going to remember that if the situation comes up.
However, in this case, getting progressively worse,(a missing plug wouldnt get worse quickly over time) it wouldnt fix OP's problem.

I have the exact same problem with my Fordor. This fall after the season's over I'm gonna try the above fix. Gonna plug it up somehow, rather than pulling the engine again! It's been out twice already...I don't wanna subscribe to the adage "3rd time's the charm"!