12 bolt w/TrueTrac
 

Why is it that Strange doesn't offer one? The way they cut splines? Space in the case? no abs, here.

Not a big Moser fan, but if it's my only choice...

Have a driver with 382rwhp waiting for h/c/i work. Time to upgrade the tired 9bolt before any problems.

Re: 12 bolt w/TrueTrac
 

The only company I know with a different spline cut is Mark Williams.

Re: 12 bolt w/TrueTrac
 

I think it is more spline depth which is different from Moser to Strange not pressure angle.
As to fitting in the case it is a bigger unit and has a different sized splined ring for abs that moser fabricates. But it does fit even though the strange is smaller internally. No need for abs here, but fitting differences inside I have to consider as well.
Does anyone have info?

Re: 12 bolt w/TrueTrac
 

Also, thinking of a hybrid floater end so custom axles are figured in to this. Just doing research and asking questions. This can use OEM components!

Re: 12 bolt w/TrueTrac
 

Moser has that also but is pricey!

Re: 12 bolt w/TrueTrac
 

Have you looked at a Mark Williams 12 bolt?

Re: 12 bolt w/TrueTrac
 

Yes, I've talked with Travis several times. Around $3600 if I recall. They're the best.
I'm hoping to get the strange housing with brackets - no ends ($950), and continue on from there - hybrid floater or uber BBF ends at minimum.
I'll exhaust my attempts at Strange first. I've heard of others using Strange w/Truetrac, but I want good info - why they don't offer, how one can make it work, what are the pitfalls, etc.

Re: 12 bolt w/TrueTrac
 

Strange replied with this:
"Our axles do not fit the 33 spline Truetrac for the 12 bolt. Our axles fit sloppy in the unit so we do not offer it."


It must be the depth as I believe Strange & Moser are 45 degree pressure angle. OR Moser's axles fit sloppy in the unit, too. Strange isn't it, :lol::lol:.

I think the Moser unit is OK - slightly lesser quality & slightly higher priced (IMHO)- but it's not that Moser is bad. The torque arm attachment can be managed and their housing ends are better.
I'll keep investigating... I wish I had more technical information to base my decision on. What's a customer to do....

Re: 12 bolt w/TrueTrac
 

Better check with strange again cuz i have one in my strange rear end

33 splines

Re: 12 bolt w/TrueTrac
 

Yeah, I know some have done it. You assembled yourself, correct?
Notice any slop in engagement between spline and diff unit?

My guess/assumption is Strange doesn't want warranty/reputation risk?

Re: 12 bolt w/TrueTrac
 

Correct i swapped mine in. Did not really notice any slop but its been awhile since i did it.

At some point in time the axle spline angles changed and at first moser was only one using the 45 deg angle or something like that. So moser axles were only ones for true trac. Then strange switched over at some point. I believe thats how it all went down but not 100% sure.

I would try to order the housing and axles with bare center and have someone setup a truetrac for you. Its a great differential. 1000 hp here thru it

Re: 12 bolt w/TrueTrac
 

Mark Williams:
4. Involute Splines

http://www.markwilliams.com/holland_...nv_splines.gif All OEM axle differentials have involute splines; their face is slightly curved to provide optimum contact and even pressure distribution during acceleration. Some aftermarket axles are made with straight-cut splines. They are not a correct engineering design and result in sloppy fitting practices. This creates high stress points, which can result in premature spline failure. Only involute spline profiles should be used to assure uniform loading and proper mating properties with spools and OEM components. In an exclusive process, splines on MW axles are hobbed while in the lathe-turning process. An MW designed (patent pending) hob attachment does the splining process in the same chucking operation as the turning. This produces extremely accurate splines that are true with the entire shaft.

Wow, you can't argue with 1000hp :goodjob:
I just might order the internals from MW. I got til Labor Day to scout for info and any specials.

Re: 12 bolt w/TrueTrac
 

The engineering above may be sound but i have no concerns in my rear end braking anytime soon. Now that may happen after alot of abuse at high power but we shall see when we get there. I already been 1.39 60 ft with wheels off the ground. Its a 3700lb pig so it sees alot of stress. I see gear breaking before axles or splines shearing off but never know

Re: 12 bolt w/TrueTrac
 

I'm planning on ordering a Strange S60 housing for my Chevelle and putting Moser housing ends and internal parts in it. Moser doesn't make a 60 for the Chevelle, so I have to use the Strange housing.

Re: 12 bolt w/TrueTrac
 

I'm running a locker in my 9" but have been thinking of going spool or truetrac but I have read some bad failure stuff about the truetrac. Maybe that's over??
Either way, my car is apart and waiting.

Re: 12 bolt w/TrueTrac
 

I'm feeling forced into the S60 by the manufacturers and by cost.:gocrazy:
Someone suggested floating calipers on rear (Wilwood D154 w/PB), but they won't fit the "Chevy Special" housing ends.:gocrazy: I'll see how difficult/expensive it would be to put BBF on it.

I guess I'm just a whiny customer.:lol: I'll figure it our after I vent, and then acquiesce to the market masters.

Re: 12 bolt w/TrueTrac
 

Contacted Strange once again, this time they said the 30 spline Truetrac fits fine, just not the 33 spline. So I guess I could order one, but it's not listed on their website. If it's a custom order, maybe I can get the BBF housing ends rather than the "Chevy special."
With <500rwhp, auto, and street tires I should be fine AND keep the weight down, too.

Re: 12 bolt w/TrueTrac
 

I'd be impressed if you break a 12 bolt 30 spline with less than 500whp in an auto

Re: 12 bolt w/TrueTrac
 

It's getting Strange(r):
Called Strange to get a price quote on the 30 spline Truetrac - they said that they were out of the Truetracs and would not have any in stock til December:confused: Sounds strange to me.
They pawned me off to DTS who quoted $2495 painted w/out S&H. They use Moser axles and have bolt-in TA mounts :eek:. I thought that DTS bought out KTRE and were using that housing. Where they bolt-in? Or maybe they're just using alot of Moser stuff. Sounds strange to me.
They want $175-200 shipped from MI to WI:eek:

Bob@BS quotes $2750 shipped for 33 spline Moser, unpainted, but does not show an option for 30 spline.

Then I contacted Eric@MWC. He said that they could build a 30 spline Truetrac, but: Strange does not offer the 30 spline axle long enough for the needed f-body widths. Only way they can do it is with the race axles, and will be a custom set. Eric says I should just go 33 spline and have Strange build it for me, but they've already said they won't. Sounds strange to me.

I can't get one answer to line up with another. I'm not set on 30 spline, but it fits my needs just fine. If I have to go up to 33, so be it. I do prefer the Strange housing, but this is all too strange for me. Do you think that Strange has just abandoned the 12bolt Truetrac market segment to Moser?

I'll continue this week to communicate w/Eric to see what he can do.

Re: 12 bolt w/TrueTrac
 

I was going to ask if you had looked at Mark Williams, but I see that I already asked that question.

Re: 12 bolt w/TrueTrac
 

They gave me a decent price on all the internals, if I go with just the Strange housing.
Unsure how they would know the axle measurements for 3rd gen, and I'm clueless. They quoted all internals 33 spline(install kit, set-20, billet driver's cap, solid spacer) for about $1k ---decent!

Re: 12 bolt w/TrueTrac
 

I need some dimensions:
Sticky says: Approx. 57" from backing plate to backing plate and 62" from axle flange to axle flange.
Is there something more definitive than 'Approx.'?
What would be the wheel - wheel dimensions?
Brake hat thickness?
center hole dimensions?

Thanks

Re: 12 bolt w/TrueTrac
 

Never pay any attention to backing plate measurements. The only thing that matters is the over all width, where the wheels mount. Backing plates are not all the same and some have more offset than others. This is a completely unreliable measurement.

Re: 12 bolt w/TrueTrac
 

Good. MW asks for a lot of measurements!
My wallet has a slimmer measurement.
Excited.

Re: 12 bolt w/TrueTrac
 

They ask a lot of questions - never thought of some before.
Ordered New Big Ford housing ends, 2.5 offset, using set-20 bearings.
Trying to figure out the brakes so I can get the backing plates to them.
Looking to put Wilwood D154 w/PB kit: http://www.wilwood.com/BrakeKits/Bra...no=140-12209-R

This kit includes a 3.06” center I.D. hat or rotor assembly and a 2.80” hub
register adapter ring to accommodate the installation of this kit on axles of
either dimension. For axles with different center register diameters, please
consult the table below for optional adapter ring sizes.
PART NO. REGISTER I.D. NOTE
NO ADAPTER USED 3.06” ROTOR CENTER HOLE I.D.
300-11732 2.86”
300-11962 2.84”
300-11338 2.82”
300-11337 2.80” SUPPLIED WITH KIT
300-11532 2.78”
300-11803 2.52”
300-11901 2.50”
300-11653 2.18”
300-11339 2.00” OPTIONAL (Machine to fit I.D.)

My Formula 16" wheels have a 70.3mm center hole ID.
Am I correct in thinking that I need the 300-11532 2.78” hub register adapter ring? Attached is the assembly instructions.

Also, on the axle flange - the maximum dimension to fit a Wilwood hat is 6.61". What is the smallest that I can get away with? - always maintaining great safety, and the 5 x 4.75 bolt pattern. I guess going custom forces you to learn!

Re: 12 bolt w/TrueTrac
 

Yes, I do need the 2.78" adapter. They wouldn't let me swap it out at time of ordering, so I have to order it separately.
Brakes came - backing plates and bearing retainers are off to MW.

Re: 12 bolt w/TrueTrac
 

Should ship next week!
https://www.thirdgen.org/forums/pict...ictureid=48138

Re: 12 bolt w/TrueTrac
 

It arrived today!
https://www.thirdgen.org/forums/pict...ictureid=48278
https://www.thirdgen.org/forums/pict...ictureid=48279
https://www.thirdgen.org/forums/pict...ictureid=48280

Re: 12 bolt w/TrueTrac
 

https://www.thirdgen.org/forums/pict...ictureid=48281
https://www.thirdgen.org/forums/pict...ictureid=48282
https://www.thirdgen.org/forums/pict...ictureid=48283

Re: 12 bolt w/TrueTrac
 

Test fitting the brake clearance. Have a slight rub, but no real resistance when I turn the wheel. It took the dirt off the wheel, but my finger-nail did not catch when I ran it across the mark. I should be able to grind a little to get clearance. These are dual piston floating (D-154) calipers.
https://www.thirdgen.org/forums/pict...ictureid=48284
You can see the slight rub.
https://www.thirdgen.org/forums/pict...ictureid=48285
https://www.thirdgen.org/forums/pict...ictureid=48286

Re: 12 bolt w/TrueTrac
 

I like it. Was the 85W140 gear oil what they recommended or was that your idea?

Re: 12 bolt w/TrueTrac
 

They recommended.
My front wheels are out 0.30 for the BBK. I'm thinking a slip-on spacer on the rear might be a good idea and give added caliper clearance.

Re: 12 bolt w/TrueTrac
 

You should weight the rear end before you put it in.

Re: 12 bolt w/TrueTrac
 

It's in!

https://www.thirdgen.org/forums/pict...ictureid=48360

And a pic of the billet 1350 yoke with u bolts. But I'll pick this up in the Spring:
http://www.markwilliams.com/detail.aspx?ID=1667

https://www.thirdgen.org/forums/pict...ictureid=48361

Re: 12 bolt w/TrueTrac
 

I just noticed your 12 has a cast in torque arm mount. Is MW the only one doing that? VERY cool. That was the biggest reason why I didn't go down the 12 route.

Re: 12 bolt w/TrueTrac
 

They use the old KTRE casting from DTS and do some proprietary tweaks. The two rear bolt holes are screw in and the front two I have a nut on - I used Loctite. This is very similar to Moser's unit, but not the same.
Strange has the bolt through design, but I just could not get what I wanted from them axle-wise, and in searching around found both Strange & Moser have similar complaint percentages from their customers. I decided that it would be best to buy parts and have an expert set it up. I wanted the Truetrac, and was forced to have Moser axles.
So I ponied-up and went to Mark Williams. Glad I did. All the little things add up and make it a value in the end (pun).
BMR trak-pac arm and drive-shaft all bolted up with no mods whatsoever. I thought I had to put in a conversion u-joint for the 1350 yoke, but low and behold I had swapped in a 1350 yoke on the 9bolt when I bought the 3.5" aluminum shaft!
Bleeding the brakes (swapped in the stiffer spring in prop valve) and I should be rolling this afternoon.

Re: 12 bolt w/TrueTrac
 

Drained the break-in gear oil. Here's pics of the wear pattern.

Re: 12 bolt w/TrueTrac
 

That's the coast side. What does the drive side look like?

Re: 12 bolt w/TrueTrac
 

Drive

Re: 12 bolt w/TrueTrac
 

It's kind of hard to tell from those pictures, but I don't see any problems with it. Is it running quiet? I think you are all right with this.

Re: 12 bolt w/TrueTrac
 

Whine was loud. It's getting better. Only have 600 miles on it. It's off-idle. Confirmed they used red Motive (Italian).
A little disappointed, but it is trending in the right direction. We'll see at 1,000 miles.

Re: 12 bolt w/TrueTrac
 

The pattern looks like the pinion might be a little too deep, but it's hard to see without any marking compound on it.