Lagonda Rapiers

4 minute(s) of a 484 minute read

I think that babbit was chosen because they were working to very tight clearances. with not a lot of material to spare. I don't know how long that material had been in there. I was sold what was supposed to be a "fully rebuilt" unit! This is the first time I have had this particular box apart. It is ten or 15 years since I fitted it. When you are buying from one of the worlds (then) leading exponents on Preselector gearboxes you expect it to be "right". My main complaint was that it has always (from day one) been very noisy in first and second gear. I now know why.

Bernie J.

5-13-2012

It is all very frustrating.

I now have completely stripped the gearbox and have failed to find anything broken or a possible source of the failure to proceed. While the box is apart I will take the opportunity to replace the very worn needle rollers in the planet gears. So that the car is off the road for as shortest time possible I will use a borrowed (wide ratio) gear set while I am rebuilding the original (close ratio) set. This means taking the box out a second time but at least I can use it and take my time with the rebuild. One good thing that has come out of this is that I have found someone locally who has new-old stock ENV parts. They may even have a complete close ratio gear set.

Bernie J.

Hello Roger 

Thank you for looking in again.

The "posts" for the needle rollers simply press out. Possibly none of the Auto trans you have rebuilt are almost 80 years old and almost certainly have not led such an "active life". The last time this particular box was apart was almost 20 years ago since then It has not only led a hard life here in Australia but on two separate occasions has spent time not all that far from your home base climbing all the historic alpine passes including the Stevio and the Col du Galibier. Added to all that I somehow doubt that you use 6,000 rpm in your Cadillacs very often. It is a pity that there is no provision for sound track to go with the photographs.

Bernie J.

Hello Roger

While the ENV Preselector gearbox is similar to a modern automatic trans in that it has epicyclic gearing the method of engagement is quite different in that it relies on a large spring to operate the brake bands as illustrated in the attached drawings. 

Bernie J.

Hello again

Sorry that was not a good choice of drawing as Top gear is in fact a cone clutch. The drawings below show the engagement of one of the intermediate gears which rely on the brake bands for engagement. The problem I had seems to be that the busbar failed to pick up a strut and with no resistance went to an over centre situation so that depressing the change pedal (Clutch) failed to compress the spring and the busbar remained in the up position.

Bernie J.