Stop reading my mind. They are pretty small gears inside- the main ones that concern me are little bevel gears that tansfer drive 90° from the propshaft to the diff gear. I know normal gears would be pretty easy for you, just wandering if bevel gears would be tricky or not? If they do fail, I'll know who to talk to anyway so thanks
Little update:
Just spent obscene amounts of money last night on the next batch if parts:
1518 motor = $157.99 + $32.50 shipping ( I expect customs to jump on that for sure, so add another £30-40 to cover import, vat & handling charges..

)
3905 tranny = £27.89 + £5.45 shipping ( got a dispatch email form the retailer earlier- they have marked the value on the package as $17, I sh!t you not

God I love ebay some times, saves me another £10-15 I reckon )
3905 slipper parts = £11.64 + £1.00 shipping, from Modelsport.co.uk
3905 single motor mount = £4.90 + £2.63 ( couldnt find them on ebay until I just searched for the part #, weird....).
Kershaw Designs FireHammer MT clear unpainted shell = £31.26 including postage ( I wanted something a little bigger than the normal maxx sized shells, will actually look a bit more like a scale truck ( like NickRummy's ), more impossing...).
Hobbycity Zippy Flightmax 5000mah 40C 5s lipos x 2 = £115.36 + £25.24 shipping ( value will be marked at 10% of actual price as per the option on the ordering page- hope to Christ customs dont get suspicious otherwise I'll get raped for customs fees etc... again).
GWS 8ch Dual Conv 40mhz FM Receiver = err, ~$25ish. Need to get some crystals for it, will look for them later this evening- most likely will get some hitec items.
EC5 5mm Connector (Pair) x 7 = ~$9ish. They look great, and are much tidier than my current wiring setup, plus easier to grip and will last longer vs the standard 5.5mm bullets I have currently (different springy mechanism- like how the smaller 3mm version feel and work that came on my hobbyshitty motors before I swapped them over to 5.5mm bullets). Will redo all gear with them, then maybe flogg the bullets after cleaning them up a bit- I have loads so will sell them as a job lot on ebay unless anyone wants them for dirt cheap?
So yeah, spent alot of money- wasnt planning on getting the motor this month, but I couldnt pass up on the black friday deal at Castle- just means that in January I will just have to get the esc and servo (when its back in stock (mid december apparently), was -2 when I went to order last night; grrrr) resulting in a cheaper month.
Esc will most likely be an MMM, cant see the MMPro liking the 1518 much in a ~15lb truck. Guess I'll need someof Mike's pinions too really, though havent crunched the numbers on that just yet- I can now though since I know all the ratios and the voltage & motor kv I'll be using etc; will have my supper of fish cakes and chips (English chips that is

), an Angel Delight for dessert (ButterScotch flavour, mmmmm) first then will hit up BrianG's calculator and do some sums.
Laters.