bowtie6‘s New Differential and Rear Suspension

bowtie6’s new frame gets a new differential.  In order to handle the power of the ECOTEC – remember boost is in the plans – we needed something that would not break.  Furthermore, one of my requirements for the new drivetrain is to have full posi-traction (and by this I mean the real deal and not viscous).

In the following gallery, you will see the following:

  • The rear axle is a narrowed 9″ Ford.  Yes, it might be a little overkill but again, this is all being built so we don’t have any unexpected “failures”.  The solid axle in this application will by far surpass the IRS as originally implemented.
  • The diff is a Motive full posi-traction unit.  It is set up with a 3.80 to 1 ratio – it is a bit tall in first gear with the Solstice’s AISIN gearbox but you have to remember this:  I am not building this to be a drag car.  With this ratio, the car is extremely quick and nimble at speed.  From the setup in my cousin Jim’s TR4, we have determined this rear axle ratio works fantastic with the engine in second, third and fourth gear; with fifth being even more fun at speed.
  • You can see in the pictures the special order Moser axles.  These were custom made with the correct length in order to handle the narrowed housing.
  • The rear axle is held in place as a four point suspension.  The control arms are fitted the special Heim ends.  These were quite pricey and come with special seals to keep dust and grit out.  Why Heim ends?  I’ll have an article about this later…
  • Finally, take a close look at the driver’s side axle:  the rear brake rotor is fitted.  Yes, we will be re-using the disc brakes we had previously used.
  • Not shown in the pictures is the all new, custom made brake lines.  We are using stainless tubing this time and it has all been hand made, and bent just special for this frame.  I’ll have a future article about this because the mounts that Jim made are real special.

6 thoughts on “bowtie6‘s New Differential and Rear Suspension

  1. Drew

    Thanks for the response and the info. I’ll look into the Ford axle and see what I can find. By the way, your TR6 is absolutely beautiful. Hopefully, mine will look that good one day. I did find a very nice hardtop and plan on having it painted to match. Love the look with the hardtop

    1. bowtie6 Post author

      Thank you for the compliment Drew!

      The hard top is nice – even with the new frame on my TR6, the hard top adds even more stiffness. And it makes the TR6 look a little more unusual, after all not many factory hard tops are out there anymore.

  2. drew baker

    Hello – I recently discovered your site and it is quite interesting. I have a 1976 TR6 that is in very good shape overall. It is unusual in that it was converted to a solid axle TR4 rear end by the previous owner. I am interested in replacing it with a more modern rear end and I saw you used a Ford rear end that had been narrowed. Do you know the specific type of Ford rear end you used so that I can do some research to see if it would work?

    1. bowtie6 Post author

      Hi Drew
      Thank you for your question. I don’t recall exactly where this rear end came from, might have been from a Mustang but I am not 100% sure – it has been quite some time. However, I do recall we had to do some surgery to it by removing the factory mounts, narrowing either side and then welding it back together. Finally, the new mounts had to be designed and welded. The axles were special order (because the housing was narrowed) as well as the gears themselves.

  3. Dennis Baumgartner

    Hi, Iam doing a project similar to yours, a 1960 A.H. 3000 .using a 07 solstice lnf with a 5 speed asian.I was wondering what you did for the drive shaft & slip yoke on your car?

    1. bowtie6 Post author

      The original Solstice driveshaft was used. The transmission side has a CV joint and we decided to use that. The differential side had to be cut and a matching yoke welded on. So basically my cousin Jim cut the driveshaft, shortened it and used a yoke to fit the diff.


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