Differential Question

[jerrybny]

Ok here goes, I'm wondering since I have my differential out so that I can have my right front bracket repaired so I so ahead and replace the axle shhaft bearings, oil seal housing and the oil seal. I do get a little drip from the driver side. Would this be a useful replace or am I wasting money. I know of no problems with it but then again I don't know what I would hear if the bearing was worn a little. Thoughts??

 

[Terry_Geiger]

Do you have the early or late differential? The early differential has a keeper that prevents the pinion nut from working loose. The later diff uses a nylon locknut to retain the pinion flange. The early differential can be safely disassembled because it does not use the crush sleeve on the pinion gear. The later differential does use the crush sleeve and usually requires special skills/tools to get set back up correctly. Some say they have done it by counting the number of turns the pinion nut turns during removal but if you do this you may get a whine in the diff because the gear mesh has changed slightly.

As far as bearings go, if you aren't getting a rumbling noise at speed, you're probably OK. Does the differential seem to have excess play? If not, I'd vote to leave it alone.

If you're getting a drip from the driver's side stub axle, that can be removed without disturbing the pinion flange. Once you get the stub axle out you can change the seal by pressing the stub axle out of the flange. This usually requires a machine shop with a press to do this job. Hammering at it with a hammer will usually distort the axle flange or the stub axle.

 

[DougF]

If your main concern is leaking, personally I believe you would be throwing your money away. When I bought my TR6 out of Arizona, it was untouched. There was no sign whatsoever of leakage from the differential. Today, after almost four summers of driving, I noticed it is leaking. I believe fixing it would be temporary at best unless you use a sealant that can handle the expansion /contraction resulting from the rustbelt climates.

 

[MarkT]

Hi Jerry,

Slightly, but only slightly, off-post. Are you welding the new supports for the diff. mount, or is someone doing it for you? And, are you/they pulling the gas tank?

I need to replace my differential mounts pretty soon - the front passenger side mount is broken - and welders I've spoken to have different opinions on whether they would do it with the gas tank in place. Sparks + petrol = not good!

Cheers,
Mark

 

[jerrybny]

Someone is doing the welding for me with the gas tank in. In fact it is done. It took the guy about 45 mins to put the reinforcement pieces in and fix the crack. Yahoo I can be driving again soon. We put wet rags about were the brackets are welded to in order to keep things cooler and put out any sparks. I am quite happy with his work. That right front bracket probably won't crack while I'm alive hopefully.

And I guess I will leave the differential bearing and oil seal alone. When I have the car up on my ramps I am able to check the fluid and top it off when needed. Plus I guess it will keep the rear part of the undercarriage rust free. /ubbthreads/images/graemlins/lol.gif

 

[tomshobby]

Probably off topic but I have seen a few mentions of working around gas tanks. Having seen far too many industrial accidents with injuries and deaths I hope you will pardon me for this sermon.

I used to do vehicle repairs and have welded many gas tanks. If there is one thing to remember about a gas tank is that once it has had gasoline in it, never, never, I said never trust an empty tank. They are the ones that explode. The gasoline will permeate the metal tank and mix with the air in the tank. And this condition will happen for many, many years after the last time the tank is used.
Full tanks will burn. So care needs to be taken around them also.

I had a method to render a tank safe to work on but in the interest of keeping someone from being killed from not completely following the procedure I am not going to divulge how to do it.

Jerry's welder/machinist sounds like he had things right when he did his work.

If I was doing the job, I would make sure the tank was full with an inch or two left. I would also have up to date fire extingushers on hand. /ubbthreads/images/graemlins/eek.gif I did have a tank fire up one time in a farm tractor and the extingushers came in rather handy. /ubbthreads/images/graemlins/yesnod.gif

I never had a tank explode but I did have one gain a few gallons of capacity once. /ubbthreads/images/graemlins/shocked.gif

Just be careful, I do not like to lose friends. In an instant things can go from routine to disaster. Besides there might be one less LBC.

 

[Aeroken]

I am in a similar boat as Jerry. My 1973 TR6 is also up on ramps/jacks being prepped for the diff mount repair. While the diff is out, I took the opportunity to change the oil. When I poured it out, I got less than 1 pint of oil out. When I filled it back up it took the full 2.7 pints AND promptly began to leak/run from the pinion seal and slowly drip from one of the axle shafts.

I have the new seals on order because I don't think I have a choice but to replace at least the pinion seal because of the severity of the leak. I am nervous about the pinion seal though because I assumed I had the "late" differential with the collapsible spacer based on my commission number (CF8584UO). However, when I looked closer, my diff has a slotted pinon nut with a lockwire which I believe is a hallmark of the early diff with the solid spacer instead of the nyloc nut with the later units. My diff number is CD53247, but I can't find any reference about which diff numbers ran for which years and I don't yet have the Heritage certificate to see if this is the original diff # (if it even lists it). Is there any other way to identify an "early" diff or can anyone tell based on the number? Does the later model diff still have the hole in the pinion shaft for the lockwire even though it is not used?

If I indeed have an early diff, am I correct that I can safely torque the pinion nut to 90-120 in-lb listed in the manual when it is put it back together?

Sorry for all the questions, but I want to make sure I understand all the risks when I undertake this repair!

Ken

 

[Andrew Mace]

I've no idea where it is on a TR6, but most differentials have a vent that is easily plugged up with grit and grime over the years. That can cause a fair amount of leakage. Best to check this first, cleaning off the vent and area around it as needed, before diving into the diff itself.

 

[Terry_Geiger]

[ QUOTE ]
However, when I looked closer, my diff has a slotted pinon nut with a lockwire which I believe is a hallmark of the early diff with the solid spacer instead of the nyloc nut with the later units.

[/ QUOTE ]
Ken, it sounds like someone has installed an earlier diff in your car.
[ QUOTE ]
Does the later model diff still have the hole in the pinion shaft for the lockwire even though it is not used?

[/ QUOTE ]
The diff on my '74 does not have the hole in the pinion shaft.

[ QUOTE ]
If I indeed have an early diff, am I correct that I can safely torque the pinion nut to 90-120 in-lb listed in the manual when it is put it back together?

[/ QUOTE ]
Yes, since you have a fixed spacer you'll be fine. Also, Andy brings out an excellent point to make sure the vent is not stopped up.

 

[Aeroken]

My suspicion is also that the diff has been replaced with an earlier one, I was just hoping for some other means to confirm it before I torque the nut down.

I knew about the vent and cleaned it all up before I changed the oil. Oil basically started running out of the pinion seal as soon as I filled the diff up with oil while it was sitting on my bench. I believe the bearings and gears are currently fine because there was no noise when the car was moving (other than the clunking/squeaking from the mount).

Thanks for the advice, I'm a bit more comfortable now.

Ken