That is a very generous offer Tim, I really appreciate that. I have never heard of the Wavetrac before, so I did a little bit of reading up on it and it sounds interesting. If things turn South with this current diff, I just may take you up on that.

I think things are getting better here the more I drive it. I've talked with a few Ford friends and several of them have told me it can take up to 200 miles or so before the chattering stops, especially if the tracloc is set up pretty tight as this one is supposed to be. I've got about 85 miles or so on it now. I'm supposed to bed the brake pads in at 150 miles...so sometime on Saturday I'm going to go for a pretty spirited drive to shake things completely out.

I sure didn't mean to start a synthetic vs dino oil argument here as that seems to be hashed out already ad nauseum. It is interesting to me though that there is still that much disagreement over the issue even after all of these years. Seems to me that once one finally hits on something that works for them, they believe in it and use it there after and there is nothing wrong with that. Hopefully the use of friction modifier in clutch type diffs is a bit clearer now though.

I'm on the road --- long trip in the '33 -- SF to LA - up the coast - and now a 725 mile drive today.


I "think" the True Trac CAN run Synthetic (I just never can remember) --- but some of these diffs can't. I never remember which ones can and can't ACCORDING to EATON (the Manufacturer). I don't think it's a ring and pinion issue -- but rather the "post mechanism" that is affected.

My point in all of this is to make sure you know what you're running and check the manufacturers specs.

the Eaton clutch posi's run on mineral based and slip additive. True tracs and most gear type LS like sythetic and no additives. The GM stuff works great and smells like grapes. :confused59:

It took me quite a while to find Eaton's recommendations for gear lube. They have CHANGED their recommended lube policy from no synthetics since I last discussed this issue with Eaton reps at SEMA. Where they were absolutely telling us NO SYNTHETICS. The world is embracing synthetics... and we all run them in various fluid applications. However, I'll stand by my original statement because EATON used to tell people No Syn. That was probably 4 years ago now.

I think that even they are confused. The last time I went to Eaton's website (less than a year ago) they even had photos up and a couple of their differential photos showed a NO SYNTHETIC across the face of the photo!! Yet checking their website today tells you that they're okay in all their applications including lockers etc. but then my next post will show you their FAQ page which states a different policy!!! WTF

I'm posting this - because I'm NOT crazy.... and I like being factual rather than the guy that says "a guy told me that his buddy said".....












Detroit Truetrac®
High quality mineral or synthetic gear lubes are required for use in Detroit Truetrac differentials. Regardless of the lube type, always use a GL5 rated lube with the least amount of friction modifier. Mineral lubes lacking friction modifiers (limited-slip additives) were historically recommended for all Truetrac applications because friction modifiers can slightly reduce the bias ratio (limited-slip aggressiveness) of Truetrac differentials. However, to address the continually increasing power outputs of modern powertrains, many vehicle manufacturers have switched to synthetic lubricants as a counter measure for increased axle temperatures and prolonged service intervals. In general, consult the vehicle owner's manual for the manufacturer's recommendations for lubrication type, weight and fill volume. This will ensure lube compatibility with the seal materials and bearings used in the axle. Eaton Performance technical support is available for any concerns in lube selection.

Now --- When I say even EATON is confused.....


This is copy and pasted directly from their FAQ page on their website for their rear ends:


http://www.eaton.com/Eaton/ProductsS...ials/index.htm





Detroit Truetrac

Q: What kind of oil should I use? Can I use synthetic? Do I need friction additive/modifier?

A: A quality petroleum/mineral based oil works best in the Truetrac units. We do not recommend synthetic oil. Friction additive/modifier is not required.




Eaton Posi

Q: What kind of oil should I use? Can I use synthetics? Do I need a friction additive/modifier?

A: Eaton Posi units perform best when using GL4 (or better) mineral/petroleum based gear oil. A four ounce bottle of friction additive/modifier is also necessary for optimum performance.



Detroit Locker

Q: What kind of oil should I use? Can I use synthetic? Do I need friction additive/modifier?

A: A quality petroleum/mineral based oil works best in the Detroit Locker units. We do not recommend synthetic oil. Friction additive/modifier is not required.

you ever think of being a private dik Greg?

:D

I use Lucas oils or the GM stuff.

Many people already think I am a dik....


LOL

That's all fine and dandy Greg...but this thread is about a FORD limited slip...not an Eaton. :D

I put another 4 ounces of friction modifier in it today and it is almost driveable now. It's good turning one direction and just a bit noisey turning the other...no more jerking or dragging feeling though.

I also bedded the brake pads in tonight (that's always fun)...and she's officially ready to race on Sunday.

I'll report back out how it goes. I did do an aggressive turn onto the highway with liberal amounts of throttle application tonight and the car certainly hooks up better than before. I WILL have to adjust my driving just a bit on course with a now properly functioning posi back in the car.

AH ..... Sorry Lance. I went straight for TrueTrac when you clearly stated it was a Trac-Lok (Spicer brand rear end).

This is exactly what made me run dino oil with my tru-trac in the first place which ultimately lead to all of my gear failures. C&R was perplexed right along with me as to what was going on since everything other than the gears looked fine, no evidence of lack of lube or overheating, the metal was being displaced on the face of the gear teeth so I believe the dino oil simply couldn't tolerate the load being put to it.