Trans Fluid in Differential - now what???

[our51super]

Hi All,

I recently noticed that transmission fluid was leaking out of my differential - so ... something is leaking in my ol' Dynaflow - but what? I had it rebuild a few years ago and replaced the - let me see if I remember this correctly - ... the outer torque ball retainer with the new kind which has a vulcanized seal on it.

Nothing leaks under or near the transmission but that rear end fluid sure looked pink.

I've replaced the fluid but obviously that's not going to fix the problem.

Thank you in advance,

[Mrbuick714]

Spring-loaded prop shaft spline seal usually takes care of this. BCA 2399

[Guest Straight eight]

Don't drive it with pink fluid in the differntial, it will spoil the gears, then you will have a problem.

You might contact Bobs Automobelia for a seal

You'll have to pull the drive shaft back to get to the seal on the drive shaft spline.

[old-tank]

I recommend drilling a hole in the torque tube just in front of the rear flange to check/drain fluid. If your car has a pinion seal and it is is good the torque tube will fill with trans fluid and it will get inside the driveshaft and give bad vibration problems. Changing the pinion seal is another (big) chore.

The part about trans fluid ruining rear ends is probably sometimes true, but personal experience is different.

My origianl 55 Special routinely filled the rear with trans fluid to the point of leaking out of the axel seals and contaminating the brakes...usually washed the brakes with gasoline and removed the fill plug to drain it back to a normal level. If I had time and money I would pull the bottom cover bolt, drain the whole thing and refill with cheap hypoid 90 that did not have the recommended wear inhibitors. Anyhow that rear went about 250,000 miles (car croaked at 374,000 mi) with various dilutions of trans fluid in the rear. I pulled ther rear end a few years ago and rebuilt it...other than a few pits in one of the pinion bearings and an axel bearing there was no abnormal wear. I just cleaned it, replaced the bearings and pinion seal...it is now happy in my CVT.

Willie

[our51super]

Thank you all for the advice. Just one more question - where do I get a spring-loaded prop shaft spline seal? Would Bob's Automobilia carry such an item or do I need to contact a place like FATSCO (I think that's the name anyway)??

Thanks again,

[JohnD1956]

Hey willie, can you delve into this a bit more? I can see trans fluid in the torque tube but not in the drive shaft? If this is the case, how would you get the fluid out of the drive shaft? Is it built in such a way as to allow the drive shaft to drain out? I am curious if this could be the problem on my 56 which also has a torque tube and a annoying vibration when pushed to 65 MPH. In my case I do not have the vibration at 50-55 mph and somewhere between 60-65 it comes on slowly but it is noticeable at 65 or more.

Thanks

John D

[old-tank]

John D

The following comments are about my 55...your 56 may have some differneces.

The fluid gets into the driveshaft either through the splines or through an imperfect weld at the rear of the driveshaft tube.

To get the fluid out of the driveshaft, drain the torque tube and hopefully it will come out where it came in. Looking at some of my 55 parts you could drill a hole in the torque tube and then into the driveshaft 4.5 inches in front of the rear flange. Otherwise remove the driveshaft from the pinion and drain/flush. The unit that I was referring to in my previous post had about a quart of fluid in the driveshaft when removed.

The vibration your are experiencing sounds like it is from fluid in the driveshaft...anything over 60 mph and the rear view mirror is a blur.

Willie

[Guest scott mich bca # 6619]

Crim,

I just went through the same problem with my 1955. Trans fluid leaking into the torque tube and then finally into the differential. I drained over 2 gallons of ATF from the rear axle plug.

Here is how I solved (I think it is solved, did it yesterday): Drilled the hole in the torque tube to drain it out. Tons came out. Replaced the front torque tube seal, that was available at the local parts supply store. Had to pull the torque tube back to disconnect it at the front, to gain access to the seal. Everything looks dry so far. I will be driving it to Rochester next week!

You DO NOT want to drive your car the way it is. Several reasons: Trans. is going to run out of fluid, torque tube will fill and become unbalanced, ATF will dilute your 90 weight gear oil in the rear end and cook your diff. gears, axle bearings, and leak through the seals onto the brakes. Depending on how bad the leak is. I can get you the part number if you need it. Are you going to try to fix this before the National? Contact me directly at scott@earlmich.com and I will give you my phone number if you want to dicuss further.

Good Luck,

Scott Mich

BCA # 6619

[Guest imported_MrEarl]

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">I recommend drilling a hole in the torque tube just in front of the rear flange to check/drain fluid. If your car has a pinion seal and it is is good the torque tube will fill with trans fluid and it will get inside the driveshaft and give bad vibration problems. Changing the pinion seal is another (big) chore.

The part about trans fluid ruining rear ends is probably sometimes true, but personal experience is different.

My origianl 55 Special routinely filled the rear with trans fluid to the point of leaking out of the axel seals and contaminating the brakes...usually washed the brakes with gasoline and removed the fill plug to drain it back to a normal level. If I had time and money I would pull the bottom cover bolt, drain the whole thing and refill with cheap hypoid 90 that did not have the recommended wear inhibitors. Anyhow that rear went about 250,000 miles (car croaked at 374,000 mi) with various dilutions of trans fluid in the rear. I pulled ther rear end a few years ago and rebuilt it...other than a few pits in one of the pinion bearings and an axel bearing there was no abnormal wear. I just cleaned it, replaced the bearings and pinion seal...it is now happy in my CVT.

Willie </div></div>

Willie, did the rear end whine while the fluid was in it. I have one that was whining when I bought it and suspect this is what is happening.The boot is shot. I have other rear ends to replace it with but might try draining and repacing with 90 weight and seeing if that will shut it up.Whattayathink

And Scott, what parts store still carried that seal. Did they have the gasket too.

[old-tank]

Lamar

I really don't remember any whine, just vibration when the driveshaft had fluid in it. Of course in those days I ignored noises unless the car stopped.

All of my 55's have a moderate whine at about 50 mph on float (driving a steady speed or slowly accelerating or decelerating) that goes away during hard acceleration/deceleration. I never noticed that either until I rebuilt my first rear...then you listen for and hear all kinds of noises.

I usually use 85W-180 in the differential. When I broke that axel on the way back from Batavia the shop that worked on it used 75W-90. It did not make any abnormal noise, but leaked so bad I had to replace it.

If you are going to change the fluid, why not pop the differential cover and inspect the gears and if they look good spray some white grease on the ring gear and see if the pattern is OK. Also with the cover off, rear wheels off the ground, check side play. One of mine had lots of play that was due to worn bearings... the whole carrier was moving side to side ( but it was quiet! )

Anyhow report your findings.

Willie