Transmission oil in differential

Ken Timmerman

Ken Timmerman

Junior Member
Just recently replaced gears in a noisy transmission. Filled transmission with 800+STP. Ran for about 300mi. Then decided to do 500mi service (trip coming up).

When I pulled differential plug a 'large' amount of oil flowed out. Then I found transmission 'empty'. Anyone have a clue as to what is problem? Thanks, Ken
 
I am not am not familiar with "800". Is it anywhere the viscosity of 600W (220/240wt)? The seal in the torque tube just behind the bearing at the U-joint end prevents the oil from traveling down to the rear end. If that seal is bad it will allow oil from the transmission to run to the rear end. When I rebuild a transmission I use a sealed bearing (inside seal removed) to reduce the loss of oil.
 
Mag is right, the seal is bad at the back of trans, its letting the trans oil flow down to the rear end
 
Is the transmission really empty ? Or is the combination you used just to 'heavy' to drain ? Had to ask.
Is any of this oil coming out of the u-joint cover ? Thats the first place it should go to.
 
Ken,
Originally the Model A trans bearing just had a rear baffle on the inside of the bearing at the rear main shaft.... make sure it's there on your trans after you "rebuilt" it. The newer bearings have the plastic "sealed" type or there are the metal shielded bearings. Either is fine although I tend to agree that removing the front side is OK for lube. Again, don't forget the inside baffle on the main shaft. I have a hard time believing the transmission was empty. I would think if it was leaking past quite a bit into the u-joint that the law of gravity and lube won't bring it all out of the trans without something else going on. Cracked case, loose plug, never filled, etc.

Don't take that personal but it happens and I've seen it.. The seal at the front of the torque tube is designed to keep the grease and lube from going down the torque tube. If it is good not too much gets past..maybe a little.

I would look at what I've described above and see if the rear trans baffle missing isn't the problem. If it is you can pull the rear end back a little, remove U-joint and rear bearing retainer and repair in the car without removing the trans from the car.

Also.. I would stick with the stock 600W lube... STP is not a lubricant so to speak and if there are many of these ( most) running the 600W then I don't see that you're making any improvement in the lubrication process. Just my 2-cents worth after working on many, and motoring many an A mile .

Keep the forum posted on your findings. Don't be embarrassed if the baffle is missing.. it happens! We wouldn't be human if we didn't make mistakes.
Larry Shepard
 
On the end of the main shaft where the u-joint bolts on is a special flat washer that has a notch on the side. The purpose of this washer is to form a dam on the end of the main shaft to prevent oil from exiting the transmission under the rear bearing where it fits over the flutes in the main shaft. The flutes engage the two slider gears, but oil can pass through the flutes under the bearing. Quite often this special washer is missing or has been replaced with an incorrect flat washer. This allows oil to escape into the u-joint housing. Behind the u-joint is the front roller bearing with a grease seal behind it. If the grease seal is shot as is often the case as they are difficult to replace, it allows the oil to flow past the seal, down the torque tube and into the differential banjo.

Tom Endy
 
I agree with Larry Shepard and Tom Endy. The washer or slinger was probably left out. Even if sealed bearings are installed the slinger must still be used or you will end up with a gap where the slinger would have been
 
Thanks to all who replied. First, let me correct my statement 'empty'. I should have said, my little finger did not find oil. Second, I misspoke should have said 600 not 800.

Finally, I confess that, a mechanic I am not. So, I will start looking through SNYDER's after investigating with the shifting tower removed. I just hope LARRYS40 is correct that the problem can be resolved without having to remove the transmission (again)!.
 
Look at page A-130 of Snyders catalog first column and you will see baffle, I refer to this part as a slinger. The part number is A-7080-B. There is also an exploded diagram on page A-129 That shows where the baffle goes. The baffle is shown as number 41. There is a similiar baffle on the front transmission ball bearing. If unsealed bearings are used and these baffles are not installed, the grease-oil can and will pass right through the bearing
 
Purdy Swoft said:
Look at page A-130 of Snyders catalog first column and you will see baffle, I refer to this part as a slinger. The part number is A-7080-B. There is also an exploded diagram on page A-129 That shows where the baffle goes. The baffle is shown as number 41. There is a similiar baffle on the front transmission ball bearing. If unsealed bearings are used and these baffles are not installed, the grease-oil can and will pass right through the bearing
Click to expand...


Purdy
Thanks for the quick lookup and clarifying the baffle . Part numbers are certainly a help so they know what is being referred to . Ken from you last response were you pulling the drain plug on bottom or the side filler plug ?
Yes, the rear trans bearing , main shaft, slider gears can be done in the car I have done it a number of times.
Keep us posted , interactive responses to problems are the learning experience for us all
Larry Shepard
 
I first posted about this about 12 years ago. Not only do you need to have the baffles but they must be the CORRECT version. The rear bearing retainer is what we consider the front half of the U-joint housing which is bolted to the rear of the transmission. There were two versions of this as shown below. The oil baffle must match the bearing retainer as shown in the attached Bulletin.

trans_bearing_ret-1.jpg
 
Thanks again. But I am a little confused. I found the two baffles. 7040 listed in the Snyders as both front (#7) and rear (#41). But then Henry put out a service bulletin
(which Marco included in his reply) where front=7080 and rear=7040. I am wondering why Synders lists both 7040 & 7080 but only shows 7040 in their exploded view.

So, I am going to order 2 of each (for insurance). And will do what you-all suggest.

Finally, Larry, I pulled the filler plug to measure oil level. And one last bit of advice if you will. I arranged a tour from Redding, CA to Ashland, OR (a 4-5 hr drive) for next week. And since I have put that much mileage on the existing trans, I am going to have oil and intend to go! Or NOT?
 
I found the problem with oil in the differential. Seems the 600W oil being put in the trans was really not 600w. A club member supplied me with 600w. The oil was thick and black. A 300 mile trip with the 'real' 600w and no more oil in the differential, all the oil stayed in the transmission!
 
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