Turbo Coupe Rear end Questions

[wv109323]

I have a 1992 GT with the 87-88 Turbo-Coupe rear end. I have been rebuilding the car for the last year and got it on the road today. I took it for a ride and the rear differential has a noise. The noise is cyclic and speed related. The noise is a muffled "Klank" Klank Klank. I jacked the car up and there is too much play in the rear differential. Holding one wheel tight and rotating the other you get the following:about 3/8" of rotation of the tire before the differential pinion moves; then another 1/2" of tire rotation as the pinion shaft rotates; then another 3/8" rotation of the tire before the two wheels are spining 1:1. My guess is the 3/8" movement(s) is slack in the axle to center section splines one side then the second side. The 1/2" movement in the center is from wear to the gears. ( Back lash and possibly pinion pre load/bearing wear)
My guess is that the axle splines to center section has excessive play. Normally, Which wears quicker the axle splines or the center section splines or both equally?
On the Turbo-coupe rear end is the axle removal the same as a Mustang? I could not find a "C" clip to allow me to pull the axles out?
If I need and can not find a 4 lug replacement axle ( I think my only options for a 4 lug axle are another 87-88 turbo coupe or a 1993 Cobra) is there a five lug axle that will fit the 87-88 Turbo Coupe housing?
Thanks in advance to anyone who gives me advice !!!!

 

[jrichker]

Five lug Turbo Coupe conversion:
Use the 94-98 axles Mustang axles. Use 1990 Mazda MPV 3.0 V6 front rotors (10", 5 lug x 4.5" pattern, 2 7/16" offset ). While you are at the auto parts store, set a TC rear rotor side by side with the Mazda rotor and they are the same except for the offset.

The next step fixes the offset problem:
Use a Maximum MotorSports 1/8 spacer (MMWS6, Maximum Motorsports, the Latemodel Mustang Performance Suspension Leader! ) between the inside of the rotor and the axle flange. The spacers may need to have the OD machined to fit properly. The stock rotor offset is 2 5/16" and the Mazda rotors are 2 7/16" offset. The 1/8" spacer puts the rotor back dead center alignment with the calipers.

The Mazda rotors are under $30 each, and I have seen them for $20 each. The MM spacers are two for $30 + $9 shipping. So the entire package costs $99. That saves $41, which most of us could find a very good use for.

 

[Carl H]

I know this is digging a thread up from the grave... but I tried this swap and the Mazda rotors didn't fit over the WMS on the SN95 axles. Seems the rotor ID is 5.5" and the WMS is 6"-ish. Think it would be ok to lathe the WMS to fit inside the rotor?

 

[jrichker]

I know this is digging a thread up from the grave... but I tried this swap and the Mazda rotors didn't fit over the WMS on the SN95 axles. Seems the rotor ID is 5.5" and the WMS is 6"-ish. Think it would be ok to lathe the WMS to fit inside the rotor?

Carl, thanks for the input. I sorry that it did not work for you. I advised all those who try this trick to set the TC and Mazda rotors side by side to check for differences.
If by WMS you mean wheel mounted spacers, it should be OK to turn them down. I would not advise doing any rework of the axle flanges.

 

[Carl H]

I meant the flange. I think it will be ok to turn it down a little bit to be honest. There is a ton of metal between the wheel stud and edge. It will only be a 1/4"-ish. Thoughts?

Maybe I will take and 1/8" from the flange and 1/8" from the inside of the rotor hat...??

 

[jrichker]

I meant the flange. I think it will be ok to turn it down a little bit to be honest. There is a ton of metal between the wheel stud and edge. It will only be a 1/4"-ish. Thoughts?

Maybe I will take and 1/8" from the flange and 1/8" from the inside of the rotor hat...??

Look very closely at the rotors before doing any modification. I am not sure of how much solid metal is there and how much might be hollow spots in the casting.

How well do the wheel spacers fit? Usually there is more clearance as you get farther away from the flange area of the brake rotor.

 

[Carl H]

I had to have my machinist take the spacers down too, as expected. I should get them back today.