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Differential ? Strange S-trac vs Eaton Tru-trac

Posted By: Stanton

Differential ? Strange S-trac vs Eaton Tru-trac - 10/11/23 04:41 PM

About to bite the bullet on a new rear end Anyone have experience with the Strange S-trac ??

I'm committed to this "helical" style diff. I wanted the Eaton Tru-trac but apparently there is no stock. They are offering the Strange S-trac. Both are the same price from Strange. Just wondering if there are any issues with the Strange unit.

Also, I'm ordering the S60 for a 69 RR. The car has been mini-tubbed and I have 15 x10 wheels with 5-1/2 backspacing. I know these fit BUT they are a tad tight and if the car is lowered at all the risk of rubbing the outer wheelhouse is almost certain. I figure since its a custom build I'll order it 1/2" narrower per side. Thoughts ??
Posted By: AndyF

Re: Differential ? Strange S-trac vs Eaton Tru-trac - 10/11/23 07:09 PM

I've used the S trac in a couple of cars. I don't have any negative feedback, they work great and don't seem to cause any problems. Must better rear differential for a street car than a locker or a clutch type.

If you know the existing length rubs then shortening the rear axle by 1/2 on each side should be fine. You should double check all clearances before you do it. Make sure that brake lines, e brake cables, tires, exhaust, etc will all still fit and work. You shouldn't have an issue with 1/2 inch on each side but best to double check before you place the order
Posted By: Stanton

Re: Differential ? Strange S-trac vs Eaton Tru-trac - 10/12/23 12:37 AM

Quote
If you know the existing length rubs then shortening the rear axle by 1/2 on each side should be fine. You should double check all clearances before you do it. Make sure that brake lines, e brake cables, tires, exhaust, etc will all still fit and work. You shouldn't have an issue with 1/2 inch on each side but best to double check before you place the order


I don't believe they rub but for the sake of 1/2" per side - which will hardly be visible - why not ! I figure I can always add a 1/2" spacer but once its built I don't want to have to take it back.

As for clearances, EVERYTHING back there is new. Brake lines will be fabbed on the new rear end. The Y-block will be in the stock location as will the line from the body. Likewise with the e-brake cables (stock drum brakes). As for the exhaust, the springs have been moved inboard so its not going to be an "off the shelf" exhaust kit.

Thanks for your input Andy. I always value what you have to say.
Posted By: AndyF

Re: Differential ? Strange S-trac vs Eaton Tru-trac - 10/12/23 02:50 AM

When I build a car I typically narrow the rearend a little more than it needs and then I adjust the wheel position with custom wheel spacers. On my Duster I used 1/2 inch spacers for the photographs but removed the spacers when driving the car. The car looked a lot "tougher" with the tires pushed all the way out, but they would rub on certain corners. I had both a customer S60 and a custom Ford 9 inch under that car. Both came from Strange and both were ordered from Doctor Diff. The S60 had a Detroit Locker in it which was a bit of a pain for street driving on certain roads. The 9 inch had the S trac in it and it worked great.

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Posted By: CSK

Re: Differential ? Strange S-trac vs Eaton Tru-trac - 10/12/23 04:06 AM

I have the S track in my S60 works great, I had an eaton one in my 8 3/4 & it was a loud rattling piece of junk, so far lots of miles on the S track & SMOOOOOTH as glass
Posted By: jbc426

Re: Differential ? Strange S-trac vs Eaton Tru-trac - 10/14/23 07:51 PM

Just be sure to use the right gear oil in an Eaton. Not sure what the S-Track's require. I ended up using the Lucas non-synthetic without Friction Modifier as spec'd by Eaton.
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