9" Ford "soft locker" diff.

blueovalfanatic · #1 (**permalink**) 10-30-2006, 12:02 PM

Well, my chassis is about complete. I have been trying to install the SVT rear brakes, which to me are a PITA. Not wanting to go through all of this again later, I have decided to go ahead and get rid of the open differential. When it comes to rear ends and transmissions, my knowledge leaves alot to be desired, so I thought id ask here.

All I know is that I currently have an "open" differential with 3.45 gears. The gears are adequate, and not worth the extra cash just to go with 3.73's or something. So basically what I need is a limited slip or "soft locker" Oh, and it is of the 28 spline variety, not 31.

Will basically any locker type differential work, or is there something I should know about part numbers, etc.? Do I just basically find the differential, knowing my gears will work or what? I do know that it will have to be set up by someone who knows what they are doing.

Thanks for any help,
Greg

byron w · #2 (**permalink**) 10-30-2006, 12:35 PM

Greg, I assume that you have a nine inch. If that is correct, I would call Currie and get a 4 pinion traction lok for your 28 spline axles. In my opinion they are as good as you can get for the money and your intended use. I am usin a 4 pinion for 31 spline in my Shell Valley car and have used that rear end since 1969, when they came out.
If you do not have a nine inch it depends on what you do have.
Byron

SuperHart · #3 (**permalink**) 10-30-2006, 01:34 PM

Greg, I would definitely consider contacting the guys running this eBay ad, tell them exactly what you want, and let them quote you a price. Valley Springs Custom Differentials. Their eBay ad lists their phone number. I bought a 3.50 9" 28 spline posi third member from them last year via eBay and couldn't be happier. They gladly supplied the proper size pinion yoke for my application at no additional cost. When I looked around for price, I couldn't find any better. They are asking $500 for a third member with NEW gears, shipping included, now. I opted for a good used set of gears rather than new gears to try and save some cash and that dropped my price close to $100. My rear is completely quiet and was set up perfectly upon arrival. They ship the unit in a plastic 5 gallon pail and it arrived in perfect condition, painted and ready to pop in. Curry is excellent for quality but I bet their price will be significantly higher than these guys.

Karl Bebout · #4 (**permalink**) 10-30-2006, 03:47 PM

Greg, I've been using a Powertrax No-Slip in my 9" live axle for more than seven years and have been satisfied with it. It has no clutches and definitely locks up both wheels. I've been running 345.55.15 BFG Drag Radials, gotten 1.6 sixty foot times and have not broken anything. It was easy to install and came with clear insturctions. Be advised, it will give the occasional click, when backing and turning. It will also give you a push if you let off the gas going around a sharp corner. Neither is as severe as produced by a locker. I like it.

blueovalfanatic · #5 (**permalink**) 10-30-2006, 07:25 PM

Thanks for the info, guys. I am wondering though what would be used from my existing third member when converting it to a limited slip type. One quote I got locally was $850 to do it! Id have SVC do it, but shipping would kill me. $500 for one from the guy on Ebay might be the best way to go...and again, I could use my existing 3.45 gears. I just wish I knew what converting mine over would consist of.

Thanks,
Greg

SuperHart · #6 (**permalink**) 10-30-2006, 07:48 PM

Greg, unless you know what you are doing you would be best advised to leave it to a pro. If you call they guys at Valley Springs Differentials and ask for a good set of used gears like I did I bet you could get the third member you want for maybe $400-425 shipping included and you know it will be right.

As far as I know, the only part that needs to be changed is the actual differential assembly that the ring gear bolts to. The trick is getting everything set up correctly. If you wanted to do the swap yourself you could remove the open end differential from the carrier, bolt the ring gear onto the posi unit and drop it back into the case. Leave the pinion alone. Then all you should really have to do is set the backlash. You could do that by purchasing a fresh posi unit with side bearings already pressed on as long as you were certain that the posi unit was the correct one for your gear ratio.

I still think your best bet is to just buy the entire third member from a reputable shop with new clutches, bearings and seals already installed and set up.

blueovalfanatic · #7 (**permalink**) 11-02-2006, 02:10 PM

Superhart- Thanks again. I called a couple times and finally got ahold of Clayton. he was very helpful, and was more than willing to answer all of my questions. As you stated, he said he could use my existing gears for a cost of $400. Thats a damn good price I think...and he even said if it didn't work out well, I could return it and exchange it for the traction lock. He even told me how to dis-assemble my existing third member to get the pinion gear out, and said to call him back if I have any trouble.

Thanks again!
Greg

SuperHart · #8 (**permalink**) 11-02-2006, 03:07 PM

Greg, glad things worked out well for you thus far. It isn't difficult to dissassemble your carrier to get the gears out. You will need an impact gun for the pinion nut probably. You say that he will allow exchange for a traction lok. What exactly are you ordering from Clayton if it isn't already a traction lok? The carrier I bought from him is a traction lok and I really like it once it got broke in. At first I had some "skipping" if I was in reverse and turning but that gradually smoothed out. Be sure to use "limited slip additive" with your gear oil and ask Clayton which weight gear oil he recommends for your carrier. 90 or 135 wt. At first I used Lucas 90 wt. gear oil which says to use for limited slip AS IS and NOT to add the additive. Because of the "skipping" I added the additive and everything smoothed out so I recommend the additive even with Lucas gear oil. Lastly, there is an outfit that has a reusable carrier to housing gasket that I really like rather than the paper one which needs sealant on both sides to prevent leaks. Finally, consider using a new carrier installation fastener kit rather than reusing the old copper washers and jam nuts. The copper washers are necessary to prevent leaking and old jam nuts usually have lost much of their staying power. If you need an installation kit, let me know. I have at least a dozen NOS kits laying around the shop. Keep us posted on your progress.

blueovalfanatic · #9 (**permalink**) 11-02-2006, 03:15 PM

He called it a "torque lock". He said something about some can make some noise as it is basically metal to metal rather than clutch type material. He said he would have the guy painstakingly assemble it to avoid any noise, and is why he said he'd swap them out if necessary if it does make any noise. He said he understands that in Cobras, the rear end is right behind the driver (good point), and he just wants his customers to be happy. He also has the "traction lock" which is $675, with their gears.

As for nuts, Shell Valley had put regular washers and nylock nuts on the third member and my dad suggested going with stainless just to avoid rusting...but the brass washers sounds good. How much do you want for the bolt or nut kit? Not sure which way I will go yet, but it's nice to consider all options.

Thanks again,
Greg

SuperHart · #10 (**permalink**) 11-02-2006, 03:29 PM

Greg, the washers are copper. The kits I have are identical to OEM Ford and run $12.50 shipping included. The resto suppliers get $20 for the same kit. I have been told that stainless fasteners are a little too soft to use in this application. I had thought about stainless too but went with the original zinc plated steel nuts because they hold better. You certainly don't want any of them loosening up on you. Ford used thick copper washers as "gaskets" to prevent leaking around the bolts. Many guys either don't use any washer or substitute a regular flat washer. The copper washers are soft enough to dig in and form a seal.

By the way, come to think of it, I bet my posi is a torque lok too, just because of the price I paid Clayton. Whatever, it's a really good unit, I like it and I thought the price was more than fair for what I received. I thought I originally had an open carrier but when I pulled it out to replace it I found that it was a torque lok with completely shot clutches.