Rebuilding the Healey Differential with the New 3.54 Gear-Set

Update: Since the original publishing of this article, Fred Crowley has sold his business, retired, and is no longer doing differential gear setups.  Instead, he is happily traveling all around the country with his wife in their RV Unit.  Happy trails, Fred!

For the NTAHC members that have purchased the new .354 gear-set, Fred Crowley has worked up the following rebuild cost. If you would like Fred to install your set please contact him. If you are not in the Dallas area, shipping cost will be added if you ship your pumpkin in to be rebuilt.

Most of the Healey differentials have not been touched since they left the factory 40 years ago. This is a real testament to how tough they are. However, if you want to replace the ring and pinion gears, now’s the time to replace the carrier and pinion bearings – after all, they are in the 40-year old range! If you’re spending the time and money to replace the gears, the job should be done right.

We have a very clean, state-of the-art shop, with the proper tools to do the job right, and we’ll provide the AAMCO Transmissions 90 day nationwide warranty on parts and labor. My technicians are top class (I’ve trained them on my Healey and it’s raced hard). If you bring your car to the shop, we’ll keep it inside. Of course we may show it off to customers – no extra charge for public viewing!

Two Alternatives:

Option 1:
You remove the pumpkin, bring it to us, and we install the ring and pinion gear, and set it up correctly as follows:

  • Labor = $130
  • Parts (Victoria British – including 8% sales tax) =$194

If we can’t reuse the existing shims to set up the pinion position and backlash, then there would be an additional cost for those shims (Again we get them from Victoria British).


  • 2 new carrier bearings
  • New Inner and outer pinion bearings AND bearing races
  • New pinion seal
  • New gasket for the pumpkin to axle housing

The steps we follow in rebuilding the rear-end are:

  • Adjust the pinion shaft/gear
  • Adjust the pinion bearing pre-load
  • Adjust the carrier bearing pre-load
  • Adjust the backlash between the ring gear and pinion gear.

Option 2:
Bring the car in. We’ll remove the differential pumpkin for you. Since this involves a bit more labor, the costs are:

  • Labor = $160.
  • Parts – as per option 1.

There would be additional parts costs if it’s necessary to replace the rear wheel bearings, seal, and hub gasket). When we get the axles out, we’ll give you a call to discuss how you want to proceed. If these additional parts are to be replaced, there is no additional labor charge.

The steps we follow in this option are:

  • Remove the rear brake drums
  • Remove the axles (We’ll examine the rear wheel bearings, seal, and hub gasket and notify you if we think they need replacing.)
  • Remove the differential pumpkin Rebuild the differential as per option 1
  • Reinstall the differential
  • Reassemble the axles, etc.
  • Replace differential oil with new.

Time frames: If you can give me about a week’s notice, and you already have the gear-sets, I can probably do it the same day, but I’d like to allow for 2 days so that I can fit it into our workflow (the main time constraint is the availability of the correct shims to set the differential up correctly – I keep a few on hand, but there may always be an exception). Additionally, I’ve been working with Don Lenschow, and we are exploring the possibility of having one or more units already built up with the 3.54 ratio, to speed up the process if necessary.

Fred Crowley
AAMCO Transmissions
1620 S. Stemmons Freeway
Lewisville, TX 75067
972-353-0066 (I-35 at Corporate Drive – just north of the Vista Ridge Shopping Center on the east side of I35, and about 1 mile north of Corporate Drive)