[Julian73]

Learn something new every day. Turns out that in middle of MY12 production Lotus changed the short ratio gear sets; while the same ratios, they are NOT interchangeable and note implies that ALL 1st - 6th sets must be changed to new part is any one must be changed and is unavailable in old PN. No sense to me ?? I can see pairs but all???

No telling if newer or older are better or worst, most likely a supplier change, but from the note it implies that old supply will eventually disappear, those needing a replacement to a single gear set may be in for a big surprise/bill.

Changeover was VIN # CH_10452 (Gearbox # 1564)

 

[scv]

Learn something new every day. Turns out that in middle of MY12 production Lotus changed the short ratio gear sets; while the same ratios, they are NOT interchangeable and note implies that ALL 1st - 6th sets must be changed to new part is any one must be changed and is unavailable in old PN. No sense to me ?? I can see pairs but all???

No telling if newer or older are better or worst, most likely a supplier change, but from the note it implies that old supply will eventually disappear, those needing a replacement to a single gear set may be in for a big surprise/bill.

Changeover was VIN # CH_10452 (Gearbox # 1564)

Thanks! Doesn't make sense to me either; if the ratios are the same, what is the change(seems would have to be a redesigned/completely different box, input/output shafts, gear design etc, etc).....Is it possible to post the source of the info?
If is a new box, would this be an effort from Lotus to address the gear rattle issue in 1st and 2nd gear often noted?Or address something else the factory is concened with? Thoughts?

 

[brgelise]

Thanks! Doesn't make sense to me either; if the ratios are the same, what is the change(seems would have to be a redesigned/completely different box, input/output shafts, gear design etc, etc).....Is it possible to post the source of the info?
If is a new box, would this be an effort from Lotus to address the gear rattle issue in 1st and 2nd gear often noted?Or address something else the factory is concened with? Thoughts?

I'll bet its just what you mention. They have improved the tolerances in the gearbox to better mate between the engine and tranny/transaxle. I don't know this for a fact but many of us have had this complaint so it has evidently been addressed.

 

[tbd_Evora]

The only parts changed are really the gears themselves, but that may mean a change in spacing to address the rattle issue.

 

[Julian73]

Source is the Lotus parts catalog. As previously mentioned, changed parts are gear sets only, the still go on same shafts. As part of a company that produces gear boxes of a different kind and with gear engineers reporting to me, I know enough that changes can be made to a gear mesh (addenda modifications, surface finish, etc) that even though "dimensionally" the same require fitting to a new mate. In fact with high speed gearing it is good practice to change gears in pairs. Now as to Lotus situation, I may be mis interpretive of the english English used, but it it implies all or nothing???? While we can get an interpretation from Lotus, as I have no need for new gears, it is meaningless to me at least for now.