Detroit True Trac 913A561

So after reading every thread I could find on this forum, and every other forum, I placed my order for a 913A561 Detroit True Trac. Just about every thread I read discussed the C-Clips being a PITA to either install or remove after installation and most everyone has stated they had to grind the spacer that is included with the True Trac. I also see Jeg's website states "2005 and up Mustang requires axle spacer modification." So I placed a call to the manufacturer and received a verbal explanation as to why we are having difficulty installing the spacer. Seems in 2005+ Ford decided to narrow the axle housing on the S197s. Tech support also mentioned the pinion shaft is slightly smaller on the OD to accommodate this narrower axle housing.

So here's my question: has anyone measured the axle end play on a stock S197 8.8" axle assembly? If I'm understanding how this set up works, the C-Clip touches the side gears when the axles are pulled outward and the pinion shaft when the axles are pushed inward. If this is truly the case, it shouldn't be too hard to take that same end play measurement and machine the True Trac axle spacer with a magnetic surface grinder to achieve the same axle end play once the True Trac has been installed. This would also eliminate the C-Clips being a PITA to install.

Can anyone confirm this or am I full of shit?

Tru trac for over 3 years, and 40K miles, no idea what spacer you are talking about. 4.56's, driven on 1000mile one way road trips.

If you are fimiliar with similar work, this will be no problem.

I didnt have any problems putting my c-clips in or with the spacer in my true trac

the spacer shown in the illustration

smoken1986 said:

I didnt have any problems putting my c-clips in or with the spacer in my true trac

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Almost every thread I read discussed the C-Clips being a bitch to install because the True Trac spacer is too wide to allow the axle to be pushed in far enough (due to the axle housing being slightly narrower on the S197s) to allow the C-Clips to be installed without a great degree of difficulty. Same with removal of the C-Clips.

tmcolegr said:

So here's my question: has anyone measured the axle end play on a stock S197 8.8" axle assembly? If I'm understanding how this set up works, the C-Clip touches the side gears when the axles are pulled outward and the pinion shaft when the axles are pushed inward. If this is truly the case, it shouldn't be too hard to take that same end play measurement and machine the True Trac axle spacer with a magnetic surface grinder to achieve the same axle end play once the True Trac has been installed. This would also eliminate the C-Clips being a PITA to install.

Can anyone confirm this or am I full of shit?

Click to expand...

Yes, I cut .015" off of it, you may need more or less but it should be about the same.

Natural1 said:

Yes, I cut .015" off of it, you may need more or less but it should be about the same.

Click to expand...

If you don't mind me asking how did you determine how much material to remove from the spacer? Did you measure axle end play using a dial indicator or feeler gauge between the end of the axle and True Trac spacer and machine the spacer accordingly or did you just machine the spacer until it allowed the axles to be moved in/out enough to easily allow the C-Clips to be installed?

I just installed mine a couple weeks ago. Just remove the ABS sensors. It allows the axle to push in further for easier removal and installation. Mine was a tiny bit tight but nothing that gave me a problem. I think I had to lightly tap the passenger side c-clip with a punch and hammer. Nothing crazy though.

And BTW, the truetrac is THE shit! I love it.

I measured the axle endplay as it was stock, with one side held stationary. Then I measured the endplay with a short piece of all-thread and two nuts acting as an adjustable spacer, because I didn't want to beat the axle ends against my snap gauges. I adjusted the nuts until I got the same measurement as stock and ground the spacer to that width.

TonyN said:

I just installed mine a couple weeks ago. Just remove the ABS sensors. It allows the axle to push in further for easier removal and installation. Mine was a tiny bit tight but nothing that gave me a problem. I think I had to lightly tap the passenger side c-clip with a punch and hammer. Nothing crazy though.

And BTW, the truetrac is THE shit! I love it.

Click to expand...

Thanks for the info, everyone's input is appreciated - even those that didn't have a problem installing the C-Clips.

As far as the True Trac being the shit - that's what Ive been told and it is that exact reason I am installing one while I have the axle housing out from under the vehicle.

Additional axle mods will include welding the LCA relocation brackets and sway bar relocation brackets, installing BMR's dual durometer upper axle housing bushing, and replacing the OEM pinion flange with Axle Exchange's pinion flange for their one piece drive shaft.

Having the differential carrier out will also allow me to replace the pinion bearing spacer and accurately measure pinion bearing preload.

Natural1 said:

I measured the axle endplay as it was stock, with one side held stationary. Then I measured the endplay with a short piece of all-thread and two nuts acting as an adjustable spacer, because I didn't want to beat the axle ends against my snap gauges. I adjusted the nuts until I got the same measurement as stock and ground the spacer to that width.

Click to expand...

Interesting procedure. I guess my point is you did measure axle end play prior to disassembly and used that stock measurement to machine your True Trac spacer in an effort to duplicate that same end play once the True Trac was installed.

tmcolegr said:

Almost every thread I read discussed the C-Clips being a bitch to install because the True Trac spacer is too wide to allow the axle to be pushed in far enough (due to the axle housing being slightly narrower on the S197s) to allow the C-Clips to be installed without a great degree of difficulty. Same with removal of the C-Clips.

Click to expand...

The spacer goes in after you have already put the c-clips in. As one other member said just remove the abs sensors so the axles go in more. I used a long pair of needle nose pliers and they went right in. Pulled the axles back out and the spacer went right in.

tmcolegr said:

Interesting procedure. I guess my point is you did measure axle end play prior to disassembly and used that stock measurement to machine your True Trac spacer in an effort to duplicate that same end play once the True Trac was installed.

Click to expand...

Yes and it may have been .017" now that I think about it.. I forget.

haven't read all the posts. getting the c clips on wasn't the problem, it was installing the spacer between the axles that can be a little tight. i just tapped it in there. i was told after time, the action of the spacer rubbing against the end of the axles will wear or polish it just enough to make removing it if necessary no big deal

tmcolegr said:

Thanks for the info, everyone's input is appreciated - even those that didn't have a problem installing the C-Clips.

As far as the True Trac being the shit - that's what Ive been told and it is that exact reason I am installing one while I have the axle housing out from under the vehicle.

Additional axle mods will include welding the LCA relocation brackets and sway bar relocation brackets, installing BMR's dual durometer upper axle housing bushing, and replacing the OEM pinion flange with Axle Exchange's pinion flange for their one piece drive shaft.

Having the differential carrier out will also allow me to replace the pinion bearing spacer and accurately measure pinion bearing preload.

Click to expand...

I know it's a bit off topic, but commenting on your additional axle mods; I just had a prothane axle housing bushing and it really tightened up the rear of the car. I'm just upset I waited this long to do it. I think you're going to like getting rid of the stock rubber one that's there.

rojizostang said:

haven't read all the posts. getting the c clips on wasn't the problem, it was installing the spacer between the axles that can be a little tight. i just tapped it in there. i was told after time, the action of the spacer rubbing against the end of the axles will wear or polish it just enough to make removing it if necessary no big deal

Click to expand...

If you have to tap the spacer in the axles have no end play. Specs call for a max. .030"

dysan said:

I know it's a bit off topic, but commenting on your additional axle mods; I just had a prothane axle housing bushing and it really tightened up the rear of the car. I'm just upset I waited this long to do it. I think you're going to like getting rid of the stock rubber one that's there.

Click to expand...

Only reason haven't replaced it before now is that it's such a bitch to do with the axle housing in the vehicle.

tmcolegr said:

If you have to tap the spacer in the axles have no end play. Specs call for a max. .030"

Click to expand...

uh oh. i never even thought about it. you reckon this could cause issues?

rojizostang said:

uh oh. i never even thought about it. you reckon this could cause issues?

Click to expand...

I don't know that it would cause an issue but it would constantly force the axle and C-Clip against the side gear due to the axle shafts not having any end play. The axle shaft and C-Clip is intended to float between the pinion shaft and side gear.

rojizostang said:

uh oh. i never even thought about it. you reckon this could cause issues?

Click to expand...

I bet you had end play after 15 minutes of driving...

I machined the spacer on initial install..In no time I had too much axle end play for my liking. I ordered another spacer, did not machine it and slipped it in no problem. Axle end play has not changed since.