Thread: Which Limited slip is best ?

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So I want to buy a Limited slip differential (LSD) for my 28 spline 9 inch. I have a Detroit locker at the moment. I don't like it. It locks up when you don't need it to. And it makes the car uncomfortable to drive. So I've been looking at the what's out there. The 3 that I like are Currie clutch type , Strange cone type and Eaton Truetrac. Of corse they all say that their product is the best. I was leaning toward the Truetrac because I think that it won't wear out as fast, but I've never been in a car that had one. Not really concerned about the price of each. They are all around the same. So has anybody got any good or bad things to say about my choices ? Or another brand that I didn't mention.
Cheers Manky

Manky, I bought the Truetrac unit for my Ford 9" based on research of the different units. I have not run mine yet, btu the spiral gear posi seemed to me to be my best alternative for the power level I have.

Originally Posted by rspears

Manky, I bought the Truetrac unit for my Ford 9" based on research of the different units. I have not run mine yet, btu the spiral gear posi seemed to me to be my best alternative for the power level I have.

I'm only making around 300HP at the wheels in a car that weighs about 2500 pounds. If I was to up grade the motor again I'd still only go to around 450HP.

i have had the same31 spline ford 4 spider clutch type for 25 years was in my tub out gto and in now my chevy its seen many bbcs last time i did a gear change it look like new. i have had the same type one in the back of my gto thats seen many hi hp bbc. but i went up to 35 axles i went locker . i do not like it..... the formoco are junk they crack thru the clutch windows and the older two spider ford are no good . but the 4 spider clutch ones are the best ones and not to hard to find .i pick them from a scrap yard . i am not a big fan of cone type. i had 3 of them under the back of my gto when they wear out there is not much you can do with them. they came stock from gm. after that i went to a chevy 12 bolt .then all 9 s in my cars have had them .as for power they will take alot of it came smoking off the cars . the fords9 i have have seen waaaaay past 500 hp for 454 to 572 and 548 with a blower. when i built my 632 i was thinking i would be pushing my luck so i went to 35 and a locker . the ford type will hold more power then the stock case .i use the HRW iron N case with big bearing and shim pack

My son Jeff put a 9" in his camaro last fall, and went with a true track. He likes it. If you do any racing, and if you happen to come out of the water box with one tire catching dry track before the other it can be hard on the clutches. Been there. Jeff did that a couple times with slicks and the posi couldn't handle it. The true track doesn't seem to mind and will turn both tires under any conditions, and still has street manners. He bought his from Danny Miller (Same as I did in my camaro). I've got a 40 spline spool & pro gears in mine. Not a real street friendly set up there.

when you set up the ford you need to set the clutch pack up very tight.to last... i drove the car to the track with T/A drag tires... but ..did not sit and eat my lunch in the water not much for burn outs if not needed tires cost to much and do not do them on the street .but they have seen very hard use .trust me on that.... ...if you want it to last i would go spool if on the track and then a street rear set up . all the track only fords i set up for track were spools and some ball bearing pinon suports when i was building my GTO drag car i had a 572 with a big shot on it i was using a HRW case with a pro gear big pin ...NO not street frendly so i went to the 35 spinle locker for street use for the 632

Originally Posted by manky

I'm only making around 300HP at the wheels in a car that weighs about 2500 pounds. If I was to up grade the motor again I'd still only go to around 450HP.

My differential came without the third member, and I bought mine with the Truetrac from Just Rear Ends in Reno, a father/son operation that is great to deal with. My concern with a clutch type was that they can tend to cracking of the carrier/clutch pack housing with hard use at power levels above 400hp at the engine. I am not saying that they fail, but the guys who specialize in rear ends day to day point to that weak point, as well as clutch packs wearing out and needing to be replaced. I was looking for reliability without hassles, and the TrueTrac is strong, a true posi for street applications, requires no friction modifiers, and is built to last the life of the vehicle with no maintenance other than an occasional fluid change. It was a little more expensive, but a good long term buy for me.

yep like i said the formoco did break thru the clutch windows. i only have seen one of them in the past 25 years and there junk. ford has not used them in 30 years. that is a good selling point for the worm gear unit . but the stock ford4 spider with no windows will hold alot of power some of the hard parts were getting hard for them but at the time DTS and others had them .weight as tire size as alot to do with this .off road guys can break a iron ball so a locker and a worm gear may be more what they would use. they see use in road racing . clutch s work fine you have to make up your mine how much money you want to spend on a unit .i used the fords and i know how to set them up. others may not ? i have not look in mine in the last 15 years when i changed it out the gear .i know a 548 blown bbc is putting out way past what your try to see and its been in others cars of mine for over 25 years all were over 500 hp engines. i must of hit the ford 9 lotto with mine or i am full of $HIT 25 year old clutchs with the same clutch pack at the time the only thing that i knew of was the locker or clutchs from ford as a 20 year old kid at the time i was not made out of money so i did use it. when it was time i used one under my 66GTO all steel3700 car at the time had a 548 14.8 soild 740 lift roller street engine in it on the street now if track only car i would of blown it up but used it on the street for two years and sold it in good working shape.i did drive the car very hard ...now there is many more units to pick thru .the 50 i would drive and race at the track and drive home so clutch can hold out but like pro said if your looking for track only then spool .but you did not ask that and you not happy with your locker .so if you find a good 4 spinder ford unit i would use it in a drop of a hat.. as for the need for friction modifiers not a big deal less your going to change out your grear oil every week

I also have a True Trac in my deuce which I purchased from Randy's Ring and Pinion, and I really like it. You do not know it is there until you need it. Great for a street car.