Auto box.

Steve Flint · Dec 16, 2017

I need some advice about my Defender 90 with Auto box conversion.
It is a 300TDI with Discovery Auto box and transfer box, My problem is that it does not change up to top gear until I am doing 58 MPH which in practice on single carriageway roads mean that when travelling at the legal limit it is regularly changing into top then down a gear as you get to a slight rise. Does anyone know if I can adjust the change speed to say 50 MPH.

Steve.

jamesmartin · Dec 16, 2017

does it kick down late or is very quick too

lynall · Dec 16, 2017

Iirc in disco it was 52mph for top gear lock out, and if you have taller tyres it might actually be correct.

Steve Flint · Dec 16, 2017

James the kickdown seems normal neither slow or fast and Lynall the Tyres are 235/85 x 16 Continental M/S.

Steve.

RobV8Defender · Dec 16, 2017

Hi Steve, mine locks out at around 55mph - so you are not far out - slightly larger types could easily be the cause.

As could kick down though, you are probably aware, the kick down cable does more than just change down gear, it does effect gear changes. To eliminate it as a cause, suggest you mark it for length, then just drive up the road and see - without the kick down - it will change gear and lock out as soon as it can.

Finally, is the Transfer Box correct - Disco’s have the 1.2 ratio fitted to give good motorway performance, standard I think is 1.4?

nesponge · Dec 16, 2017

I'm thinking he has the disco transfer box fitted as well. Would make sense.

There should be a sticker on the transfer box denoting its ratio.

1:4 is defender.... 1:2 is discovery.

Easy enough job to source a defender box and bolt it up.

Steve Flint · Dec 16, 2017

Thanks Rob. I will try that, It is a Disco transfer box 1:2 ratio.

Steve.

RobV8Defender · Dec 16, 2017

Just as a note, the Ashcroft Transmissions site states that you should not run the Autobox without the kick down connected - so suggest you do as short a trip to prove the point as possible.

Steve Flint · Dec 16, 2017

OK Rob will do

jamesmartin · Dec 16, 2017

lynall said:
Iirc in disco it was 52mph for top gear lock out, and if you have taller tyres it might actually be correct.

this is the answer imo,

Sirronluap · Dec 16, 2017

My Disco 1 auto's on 235 70 R16 would lock up nicely at 48mph and that's what I aspire to achieve in our 90 as well.
Much more civilised!
My fender is exactly the same set up as yours Steve also having the standard 235/85/R16's.
It too locks up at 54 and like yours no good and sometimes never getting into 'top' as it were!

Ok round the lanes and brilliant at speed on fast open roads - unless a long incline.

Similarly my task is also to change out for a 1.410 which should fix it .....as has been advised.
Just so that you know you are not alone.....

Be interested to hear what your kick down cable settings find as has been suggested

.....and also, for the discussion, though more involved, would an alternative torque converter do the job if for any reason one wants to keep the 1.222?

discool · Dec 16, 2017

A Disco 1 diesel or petrol the auto box will go into direct drive at around 52mph (4th and the direct drive clutch
engage simultaneously) when road speed drops to around 47mph direct drive will disengage with the box remaining in 4th gear.
That's how D1s left the factory, anything other than that, make your own mind up on that.
Its always been known that the auto box fitted by the factory was not suited to the D1 diesel with LR trying to improve things with the introduction of 'electronic diesel control' with the 300 series.

lynall · Dec 16, 2017

discool said:
A Disco 1 diesel or petrol the auto box will go into direct drive at around 52mph (4th and the direct drive clutch
engage simultaneously) when road speed drops to around 47mph direct drive will disengage with the box remaining in 4th gear.
That's how D1s left the factory, anything other than that, make your own mind up on that.
Its always been known that the auto box fitted by the factory was not suited to the D1 diesel with LR trying to improve things with the introduction of 'electronic diesel control' with the 300 series.

Even when EDC came out in 1995 the box was still the same mech 4 speed auto, the box went elec control when the td5 model came out.
EDC models had an extra 9bhp

Disco1BFG · Dec 17, 2017

lynall said:
Even when EDC came out in 1995 the box was still the same mech 4 speed auto, the box went elec control when the td5 model came out.
EDC models had an extra 9bhp

Agreed - 'cept EDC produced another 11 Bhp

.....

Auto box.

Steve Flint

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jamesmartin

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Steve Flint

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