So what are my options here, 9" tracloc clutch wear?

[SSLance]

This is the third member out of my car, it's a tracloc diff with about 15,000 pretty hard miles on it, lots of autocross and several hard track days on it. Last summer I put new bearings in it chasing a vibration, there was a little bit of pinion bearing wear at the time. It's been good since but the posi has been getting weaker and weaker, I'm able to drive through it on exit on both left and right hand turns lately.

It really took some abuse at the USCA event last week and I noticed considerable backlash or play on the pass side axle to diff. The driver side and drive shaft backlash feel good still. I pulled the third member today and found I can do this using the axle to move the spline on the pass side while the driver side and yoke don't move.

kLK4v7T1444

The gears look great, and there was very little foreign substance in the gear oil I drained out of it though a cheesecloth.

I think it's just wore clutches in the tracloc but know almost nothing about how they work. Is it worth just rebuilding the posi or spending the $750-1000 to upgrade to a trutrac?

I was looking at a total upgrade because I feared I'd find plenty of carnage inside, once I got it out and after seeing the gear oil, I'm rethinking that now.

What say you? Can I rebuild this myself? Can I find a reputable shop that can rebuild the posi at a reasonable price or can I replace the posi with a trutrac myself with having to turn to a professional to set it up?

Remember, I'm on a budget here...and somewhat of a timeframe to get it back to the track.

The good news is, the new tapered bearings on the axles seemed to have held up real well.

[Sieg]

I don't have any experience or knowledge of the Tracloc but Summit has this rebuild kit: http://www.summitracing.com/parts/yga-16027/overview/

.........or install this in and hope you get lucky with the set up. http://www.summitracing.com/parts/dtl-913a586

I have a very good rear old differential guy here local and I've heard too many bad set ups by so called 'professionals' so I didn't hesitate to take my 12 bolt out and deliver it when I changed ring and pinion ratios.........guess what, it's silent and the lash is beautiful.

[SSLance]

So I have found a freshly rebuilt tracloc posi unit here locally that I trust has been rebuilt with extreme performance in mind, and I can get a deal on it. I'm leaning this direction as a stop gap until I can afford to upgrade to a trutrac.

I'm wondering now if replacing the tracloc is something I can do myself or if I should still take it to a diff shop to get that install\swap done?

I've never had a 9" center section apart before, is this the kind of deal where I can just keep track of the shims as I take it apart and get it back together just like it was before?

[cjfirstgen]

Take a look at the Strange S-Trac. Many good reviews with a lifetime wty. It is what I went with after researching. I have no personal experience yet but all indications are positive.

http://i305.photobucket.com/albums/nn232/cjfar_2008/1969%20Camaro%20RS_SS%20ZZ572%20PT/AC4442C3-390F-4963-A286-5E41857357AF_zpswzdw3ryy.jpg

http://i305.photobucket.com/albums/nn232/cjfar_2008/Camaro%20Parts%20For%20Sale/Strange%20diffs_zpsta8j2omn.jpg

[Vince@Meanstreets]

So I have found a freshly rebuilt tracloc posi unit here locally that I trust has been rebuilt with extreme performance in mind, and I can get a deal on it. I'm leaning this direction as a stop gap until I can afford to upgrade to a trutrac.

I'm wondering now if replacing the tracloc is something I can do myself or if I should still take it to a diff shop to get that install\swap done?

I've never had a 9" center section apart before, is this the kind of deal where I can just keep track of the shims as I take it apart and get it back together just like it was before?

Its fairly easy compared to a GM unit. No shims to set back lash. Rotating plate and lock bolts. Just figure what you need to get the pinion gear centered. You can calculate the shims used by the depth written on the gear face and what shims and depth on the old gear.

[SSLance]

If the only thing I'm changing out is the carrier, new tracloc for old tracloc, can my internet friends walk a newbie through this?

Should just be apples to apples right?

[MeanMike]

Measure your old backlash.
Remove diff
Swap gear to new diff and add new carrier bearings.
Reinstall diff matching old backlash
Verify pattern
Beat if for another 15k miles.

As long as the backlash is the same, the pattern should be identical. If it's not, the gear isn't flat or something odd.

Edit. I read your post above. The 9" used screw in adjusters on each side of the carrier, not shims. You move both to move the diff side to side to set backlash. You also create the preload with them. It's actually easier than shims.

[Vince@Meanstreets]

If the only thing I'm changing out is the carrier, new tracloc for old tracloc, can my internet friends walk a newbie through this?

Should just be apples to apples right?

Oh same gears, just what mean mike said. Go by backlash. But when ever I use the old gears I always mark the teeth so they mesh as they came out.

[SSLance]

Thanks guys... I found out that a local shop I use and trust has a guy that is very experienced at setting these up for road racing and autox use. I'm going to take my third member and the newly rebuilt trac loc my friend has to him and use his best judgement as to whether I should let him rebuild my clutch pack or just install the new unit.

My concern is getting the clutch preload just right so the torque bias is strong enough to keep torque on both wheels during corner exit but not so strong that it's dragging a tire during a corner.

I don't want to learn this myself with trial by fire, I'd rather defer to an expert and blame him if it's wrong. :D

[GregWeld]

I can't add to your "issue" Lance --- but to others reading this -- please note the use of PETROLEUM vs SYNTHETIC gear oils.... cone and helical gear rear ends require PETROLEUM gear lubes. NOT synthetic.

I've posted this info on Lat G before... and while it seems "odd" - since it's common for us to want to use "the best"... and we have come to embrace Synthetics. Not all applications want it. It's TOO slippery.

[cjfirstgen]

I can't add to your "issue" Lance --- but to others reading this -- please note the use of PETROLEUM vs SYNTHETIC gear oils.... cone and helical gear rear ends require PETROLEUM gear lubes. NOT synthetic.

I've posted this info on Lat G before... and while it seems "odd" - since it's common for us to want to use "the best"... and we have come to embrace Synthetics. Not all applications want it. It's TOO slippery.

And especially if the gears are REM treated.

[SSLance]

Little update on this...

I picked up the rebuilt TracLoc and had my local shop install it in my third member. There was then plenty of discussion about what gear oil to run in it and friction modifier or no friction modifier... etc etc...

I've used just about every combination in the last one in the past 5 years, dino oil only, dino with modifier, synthetic, synthetic with modifier and lastly Royal Purple with a modifier already in it.

Frankly, for driving purposes I could not tell any difference between the different oils. Temps felt pretty much the same when being beat on...only difference I noticed was when I was fighting sealing issues, the synthetic would leak more than the dino oil. It's had the same ring and pinion gear in it since new, and they still look great.

The main part of the discussion was around the friction modifier and how it worked with the clutch pak. I always thought that the modifier was to help the clutch discs grab, but apparently the opposite is true. It is in there to help the clutches slip turning. I was talked into NOT running the friction modifier to help the clutches grab more therefore creating better torque bias when cornering on track.

So in went 3 quarts of Lucas Synthetic blend 75W-90 gear oil (new for me, about the only one I haven't tried before) and a test drive. The Lucas was the only synthetic without a modifier already added.

The car is barely driveable...it's fine in a straight line but acts and sounds like the whole rear end is coming out from under it while in any sort of a turn. While doing multiple figure 8s in a parking lot it gets much better, but as soon as you drive it in a straight line for a bit it starts to get very noisy and grabby in a turn again.

I decided to go to the horses mouth and talked with the person that did the rebuild on the TracLoc. He said Most Definitely a friction modifier of some sort is necessary with this type of clutch posi...no matter what gear oil you run. He also said that he set it up a bit tighter than a stock setup knowing that it was going into a 3500# car that will see abuse. His advice was to put some friction modifier in it and be patient as it breaks in...it'l take a bit longer to wear the clutches in a bit but it'll be better in the end than a stock type rebuild.

So I put 7 ounces of friction modifier suitable for synthetic gear oil in it before driving home last night and stopped in a parking lot on the way home and did many more figure 8s trying to get the modifier to embed into the clutch discs. So far, no difference. I've only got about 50 miles on it so far, and only 17 or so with the modifier in it...so I'll keep driving it and see what happens. It pains me though to hear and feel noises like that coming from under the car.

Maybe I should have found the extra $1,000 it was going to take to set myself up with a Trutrac...time will tell I guess. If this wears in and settles down like the guy that built it says it will, it should work fine for me, I just don't remember my last one having this much trouble breaking the clutches in.

[GregWeld]

Everybody is an engineer.


If you go straight to the rear end manufacturer - you know - the people that actually build them - test them - race them.... they'll tell you the correct info based on having manufactured millions of 'em.


NO SYNTHETIC GEAR LUBE.


Okay - that's all I'm going to say about that.

[Blake Foster]

I can't add to your "issue" Lance --- but to others reading this -- please note the use of PETROLEUM vs SYNTHETIC gear oils.... cone and helical gear rear ends require PETROLEUM gear lubes. NOT synthetic.

I've posted this info on Lat G before... and while it seems "odd" - since it's common for us to want to use "the best"... and we have come to embrace Synthetics. Not all applications want it. It's TOO slippery.

so just to play the devil's advocate, why then does Mark Williams recommend and supply Synthetic with their diffs? the guy who builds our center sections recommends Synthetics, I have only ever used synthetics with no issue UNTILL we had Currie build some third members and they will void the warranty if you use synthetics. all 3 of these companies use the same gears and diffs (because you really have no option) we have actually started to spec US Gear.as Motive seems to be really inconsistent.

I know this just confuses the matter but there seem to be some differences of opinion.

So when I finished my Nova we loaded it up at took it to the local road course. put 15 laps on it, this is brand new Royal Purple 85-140 gear oil, well SOMEONE didn't install a breather in the housing :badidea: it got SO hot and built up enough pressure that it pushed the pinion seal out. and all the oil with it. loaded the car in the trailer back to the shop......... 3 hours later it was still to hot to hold on to!! and that was with an Aluminum Center section also...no abnormal gear wear new seal oil off we go still running strong today.
i like synthetic

[SSLance]

There are a couple of different scenarios at play here Greg, each with different circumstances, needs and results. In regards to strictly gears...I agree that new ring and pinion gears need dino oil used with them until they are broken in. Once broken in though, I see no reason why synthetic gear oil can't be used on ring and pinion gears. My ring and pinion gears were broken in on dino oil but have had synthetic run on them for the last couple of years...and they have seen a ton of abuse and still look perfect.

Now, differentials...are another circumstance. Gear type lockers...I'm not sure what's best to use with them and when as I've never owned one.

Clutch type posi's though...from one horses mouth that builds and races a lot of these...dino or synthetic gear oil is fine either way...as long as a friction modifier is used to help the clutches slip. I can't see why being "too slippery" would be a deterrent at least when breaking in a new clutch type posi, especially after dealing with this the last few days...

rtyljdSWDas

Now I'm not an expert, but I have just listened to a LOT of them...with lots of different thoughts on this. :D I just wanted to post this to show that not all diffs are apples to apples, different scenarios are at play here.

[DBasher]

I'd look at the tapered bearings and make sure the races are set up correctly...:sieg:

[SSLance]

Don't think for a second that that hasn't crossed my mind... :buttkick:

It's gotten much better since I put the friction modifier in it. I'm going to try to get it to 200 miles before my race on Sunday and hopefully it'll be fully broke in by then.

[GregWeld]

Just go to the manufacturer website. I don't need to argue it further. Some of their rear ends can use synthetics and some can't. The key is to know which can and can't. I'm just using the data off eatons website.

[71RS/SS396]

Everybody is an engineer.


If you go straight to the rear end manufacturer - you know - the people that actually build them - test them - race them.... they'll tell you the correct info based on having manufactured millions of 'em.


NO SYNTHETIC GEAR LUBE.


Okay - that's all I'm going to say about that.

I was told this multiple times but after smoking several gears in succession, 1 set didn't even make it through 1 trackday, these were REM finished gears and the 3rd member was dynoed. I changed to Mobil 1 LSD on recommendation of C&R Racing and have had zero issues with the Tru-trac or gears since.

[71RS/SS396]

Lance, if you can't get this worked out... I have a freshly rebuilt 31 spline wavetrac if you need it. You pay for the shipping and install it, if it works out for you pay me whatever you feel it worth, if it doesn't work in your car use it for a paper weight or throw it in the dumpster... I have no use for it since it doesn't work with a floater unless you capture the axles somehow.

[SSLance]

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.

[GregWeld]

I was told this multiple times but after smoking several gears in succession, 1 set didn't even make it through 1 trackday, these were REM finished gears and the 3rd member was dynoed. I changed to Mobil 1 LSD on recommendation of C&R Racing and have had zero issues with the Tru-trac or gears since.




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.

[Vince@Meanstreets]

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:

[GregWeld]

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.

[GregWeld]

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/ProductsServices/Vehicle/Differentials/FAQforDifferentials/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.

[Vince@Meanstreets]

you ever think of being a private dik Greg?

:D

I use Lucas oils or the GM stuff.

[GregWeld]

you ever think of being a private dik Greg?

:D





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


LOL

[SSLance]

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.

[GregWeld]

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

[71RS/SS396]

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/ProductsServices/Vehicle/Differentials/FAQforDifferentials/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.

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.

[SSLance]

So the diff held up fine through my first race on it. It certainly is better with corner exit grip, the other one had been giving up for a while it seems.

The clutches still chatter a bit every now and then, but 75% of the time are fine...so I think it's going to finish breaking in just fine.

I'm still trying to figure out a way to finagle a floater rear end with a TruTrac and a set of new brakes front and rear...but in the mean time, I'll just make do with what I've got for now. :D