New Healey Owner - BT7 Transmission Question

Some weeks ago, I joined the forum and appreciated the advice I was given as I began my search for my first old car.

Last week I bought a unique 1959 BT7 that has less than 25,000 actual miles and a smashing
(almost concours) restoration.

I noticed when I was test driving the car that
First gear in particularly made a racket as the car sped up, and then the noise lessened greatly in second and no noise at all in third and fourth. The car drives wonderfully but the clatter coming from the gearbox in First makes me not want to use the gear. I am grateful for any thoughts about diagnostics and what I am looking at. I am open to replacing the tranny and would love to have a synchronized transmission.

Thanks Will Harrison

Hi Will,

The Healey first gear wears faster than the others. I was able to quiet mine down significantly by using Redline transmission oil which also gave me smoother shifting in all the gears. I bought MTL90 but later read that MT90 is slightly heavier and better suited for the Healey gearbox. There have been some reports of more gearbox leaks with the Redline ... probably some of the same slippery qualities that helps improve shifting but for me the advantages outweigh the occasional drip.

With the 3.90 rear end you can easily start off in 2nd gear ... 1st is just too low for anything but steep hill starts. With the 3.54 ratio 1st gear becomes much more useful.

The only problem with converting to a Toyota gearbox is losing Overdrive. I love using OD in 3rd and 4th especially on winding mountain roads. It's really part of the unique character of the car and to me, very important.

Another thought about non-synchro first gear. At a stop I always shift into 2nd before sliding it forward into first ... it aligns the gears and avoids the crunch.

John

Will:

From your description, one or more gears could be involved.
The laygear (or cluster gear) is the most likely to be causing the first gear noise, but it could be the first speed gear itself. Unfortunately, it is usually both gears having chipped teeth. Does reverse also make the same noise as first gear? If so, it may only be the laygear that is the problem.
Your second gear noise may also be only the laygear or could also involve the second speed gear itself.

What often happens is that a chunk will get knocked off the laygear, first gear, or reverse gear during an inappropriate gear change into first or reverse(i.e. not at a dead stop), and the dislodged chunk will float between one the helical gears and the laygear (which are constant mesh), causing really bad things to happen. Sounds like yours.

Looking at Moss Motors catalog, the Second speed gear and the first speed gear is available, new. The Laygear is a problem, and would have to be had second hand. It seems to me that some enterprising person had, at one time, been refurbishing laygears by welding a new spur gear on the end.

Also, I found a couple of pages regarding gearbox conversions:
https://www.austinhealeyclub.co.uk/tech_toyota.html
https://members.aol.com/bgahc/jwha_smittys-transmission.html

Hope this helps

Regards,
John Morrison

https://www.austinhealeyclub.co.uk/tech_toyota.html
https://members.aol.com/bgahc/jwha_smittys-transmission.html

Hi John,

You will be interested to know the Laygear is now being reproduced by Limora in Germany. I've heard that this company is somehow affiliated with SC Healey Parts. www.limora.de but the site is in German only. I've heard mixed reports on the welded gears ... something about not being able to heat treat to full effect, they are soft and wear very quickly.

John