Gearbox

[redcorgi]

At present am rebuilding a948cc smooth case gearbox & now close to completion my intension is to use the old style 803cc gearstick from the original gearbox having read the instructions from Mirabelle classics it looks quite straight forward, any pitfalls ? or advice gladly received, also your thoughts on upgraded front seal. Thanks

[philthehill]

I am not aware currently of a commercially available front neoprene seal conversion for the 948cc smooth case gearbox. You could try Heathrow Transmissions as there was a reference to a smooth case conversion front cover seal mentioned in an earlier post.
If you have access to a lathe you can convert the front gearbox cover yourself.
I did put a post on here showing the conversion I carried out to a smooth case gearbox front cover including the oil seal sizes/part numbers.
viewtopic.php?f=4&t=72415&p=662575&hili ... al#p662575
viewtopic.php?f=4&t=71037&p=645694&hilit=seal#p645694

gearbox front plate 3.JPG (1.58 MiB) Viewed 1062 times

gearbox front plate seal 9.JPG (1.51 MiB) Viewed 1062 times

[ianmack]

I have assembled a 948 box with an 803 rear end and change mechanism. It all slots together without modification. You need to use the right rods as the 803 has a lift and engage reverse while the 948 engages against a spring.
A 1098/803 conversion is more complicated as some machining is required.

[myoldjalopy]

In addition to swapping the reverse selector rod from the 803 to the 948 box (to prevent accidentally going into reverse when trying to select 4th), the 803 speedo drive gear should be swapped onto the 948 main shaft as well....

[liammonty]

As above really. The Mirabelle Classics write-up (actually from Minor Matters) covers it, but just make sure you do the bit that is mentioned in the paragraph below the main steps as well, regarding changing the reverse selector. You'll curse yourself if you don't do it, as you'll forever be at risk of hitting reverse gear when trying to select 4th. I did this change on my Series II a few years back, and together with a 948 engine and 4.55:1 final drive, it transformed the car.

[redcorgi]

Thanks guys for all the information sounds like am on the right track, the front seal on the gearbox is the C&A 2a 3087 i nave no access to a lathe, but know a guy who has going to give it a go finger crossed it all works out up date when complete.