I have retro-fit the gear box top-fill cap and retainer spring from a SII gear box, together with a modified SII transmission tunnel cover. This means I can now fill the gear box from directly above, no longer requiring the messy, time consuming and awkward use of a length of garden hose or the removal of the cubby box to refill the gear box. The breather on the new cap was filled with silicone, while the LT77 remote breather I had on the original selector cover’s blanking plate has been relocated to the upper breather position on the square top plate at the aft of the box. I also fit a new w16x2.5mm rubber O-ring to the bottom of the gear stick as the old one had become slightly abraded and flattened, allowing the the gear stick to rattle slightly on occasion. The original O-ring was 14×2.5mm, but the slightly larger size of the new one, while small enough to be positively secure in its groove, is loose enough to rotate freely, so it shouldn’t wear as quickly form the sliding movements when selecting gears.
The new reverse-inhibit flap (that had been in that antique packaging) turned out to be for the earlier reverse selector shafts, and would not fit my unit, so has been kept in the spares box for use on my hoped-for future Lightweight project. The original hinge has had its cracked weld repaired and is back in perfect order. The differences betweeen the two versions of the hinge are that they have different orientation of the securing bolt holes, and the earlier models don’t have the bracket at the rear of the top flap which engages the reverse light switch.
Access to the top-filler is through the circular hole in the tunnel cover, normally filled with a second domed rubber cap like on the side of a SIII tunnel cover. The Wright Off Road matting would normally have made access to this filler hole difficult, so I have cut the main mat into three sections, separating each foot well section from the tunnel section. This means that each section is now easily removed without having to lift out the whole floor covering, which was very awkward and heavy. It also means that the tunnel section can be lifted out without having to remove any of the selector levers or their gaiters.
At the same time, I also modified the aluminium tunnel cover itself so that the floor panels would no longer need to be removed to lift out the tunnel cover. The horizontal flanges were completely removed from the SII cover, while an old and damaged SIII cover had its sides cut to leave only the bottom 1.5″ and the front and rear edges up to and including the securing bolt holes. These cut down pieces are now fitted so that they support the floor panels, with the trimmed SII cover bolting down on top of them. The rear right corner of the upper cover was also cut away to make sure that it could be removed and refitted without having to remove the overdrive lever. The lower portions were covered in neoprene sheet to prevent rattles and squeaks between them and the upper cover.
The end result is a gear box that can have its selectors removed without even removing the foot well mats, never mind floors and operating linkages.
Why stay with the old series 3 gear boxs? And tell more in fitting discovery diffs. I would like to put CV joints in my 88 and make it full time 4wd. Thanks Steven
Hi Steve,
I think I have mentioned the reasoning behind the mechanical choices at a few relevant points in the blog, but it’s a lot of information to trawl back through if you haven’t been following it from the start.
I kept the original transmission for a few reasons – firstly, the vehicle was originally going to be rebuilt to the same spec as it was prior to the project (12J 2.5nad engine), so the original transmission would be sufficient. Secondly, I like the character of the Series transmission; the throw of the gear stick and aesthetic of the transfer box levers are unique. Third, the Series transfer box is simpler, more reliable and more rugged than the LT230. Fourthly, and perhaps most importantly, fitting an LT77 and LT230 would require extensive chassis alterations, losing me not only the points for the transmission but also the chassis, preventing me from retaining an original VIN, registration and tax exempt status.
Despite the subsequent engine upgrade, the transmission is proving quite capable, if now a little under-geared. This will be resolved with the new axles.
For clarification, I am not swapping just the differentials; I am swapping the entire axles. The root of the project was to improve braking, steering lock and lateral stability while also eliminating the steering kick when turning in 4wd. It took me quite some time to decide to retain the taller differentials in the new axles rather than to swap the 109’s current diffs into the new axles (retaining the current overall gearing).
Paul Heystee sells a CV conversion kit for Series axles, or you can try to find a Stage I V8 front axle and retro-fit a 4.71 standard Series diff to it unless you want to swap the entire axle to a coiler’s like me. It would require the rear axle to be swapped too because of the difference in length. There is generally not much need for full time 4wd, though – it does improve road handling, but not by much on an old leaf sprung vehicle with such lowly geared steering, and even less on an 88″, which is not the most stable wheel base for road use.
Fantastic idea to modify the tunnel cover – having spent a ‘happy’ few hours trying to remove a 30+ year old lightweight floor just to change the reverse flap springs, it seems like the obvious modification to make.
Thx Rob