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Gearbox LT85 - rebuild or swap for R380 ?


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Gearbox LT85 - rebuild or swap for R380 ?

I need to get on with re-building my 1989 110 V8 Pick-up

It needs a new Chassis, (Galv from Richards) and the clutch is gone - so its going to be in pieces. I have an Santana LT85 gearbox that howls in all gears except 4th / straight through.

Id quite like to keep the box, but I also have a GKN Overdrive (new and in the box) and As I understand it I cant use that with the LT85?

Or should I fit an R380 with lower ratios in the transfer box and use the GKN Overdrive?

I had a GKN Overdrive on my 110 300 Tdi and it transformed the vehicle, especially when towing - and yes it was unreliable (still is) but I can live with that.

I don't want an autobox!

Cheers

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Lt85 but I'm biased

R380 will require the short bellhousing variant

It would depend upon application (do you want or need the lower ratios?). Given you've got an lt85 and the common failure I was told was bearing failure 5th gear lack of lubrication plus high speed operation, I would a) get an ashcroft rebuild or b) if cash strapped had time on my hands have a go at rebuilding it myself besides the bearings and gasket kit I'd suggest you'll need an output shaft too given the spline wear I saw on mine (sorry bad design in my opinion)

Hopefully someone in the know will pop in shortly about lt85 longevity and rebuild

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I had this converstaion with Dave at Ashcrofts when I blew mine apart (LT85)

The key biots are

LT85 technically / regarded as "Slightly" stronger

But noiser / more agriculatral

R380 tapered bearings quieter smoother / not as strong

LT85 = 20/50

R380 = very spendy special oil

Solid LT85 casing Boxes regarded as stronger then LT85 Split

Hope this helps

Nige

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The lt85 solid case is in standard quite a bit stronger for longer than a standard r 380 . especially behind a V8 . I sadly moved to a r380 behind my td6 , as the oe lt85 was noisy behind the td6 , but that might have been a alignment issue caused by the home made bellhousing adapter . It was then a financial consideration , (as well as a lot of extra work) if i had it rebuilt , refitted it with same result , so i went for r380 using standard bellhousing , and having the big bearing conversion done by ashcrofts , also with oil cooler, and redline synthetic oil , will now see if it can survive for reasonable time ! From my experience the gearchange speed etc is no different between them , and the lt 85 stays more precise over time . I think the overdrive is more dependent on the suffix of the lt230 not what gearbox is in front of it . HTSH

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I would be inclined to sort out the LT85. It is supposed to be stronger, and looking at the internals, it probably is, but it is and older design of gearbox, and as has been said, a bit more agricultural/less nice to use.............apparently

Having had a R380 lose its 4th and 5th gear on me, I am personally not over enamoured with them in any case, and do not consider them more "reliable" than the LT85 or the LT77S come to that.

The gearchange may.........or may not be "nicer" but they are known to be variable in that respect, whereas IMO the LT85 is fine, but cannot be rushed. It depends on your driving style I guess.

If you DO go down the R380 or the LT77S route, get the box complete with bellhousing from a V8 Disco 1 as it will bolt straight up. You may need Defender type gearbox brackets though, TBH I cannot remember

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I had an LT85 behind my 4.6 and it coped very well.

Also had a GKN overdrive which worked very well.

You need to make sure you have the right number of teeth and depth of gear in your LT230. I can't remember number of teeth (I think 26 but please research) and it must be the broader gear (bigger depth/ height of input gear)

Neil

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Really simple to check nothing complex

If it's got a smooth casing without any crosshatch sort of raised casing it's a solid casing

If it looks like it's got a hatched casing with bracing and support to the aluminium casting (looks like a cross pattern) it's a split casing (row of bolts across the bottom centreline too)

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