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Suggestions: Upgraded Automatic Gearbox for 50th

 
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novice_mechanic_1
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PostPosted: Sun Feb 26, 2006 4:33 pm    Post subject: Suggestions: Upgraded Automatic Gearbox for 50th Reply with quote

Hi,
I am looking for a way of upgrading my gearbox on my 50th, should I change the gearbox to something like a 5-speed automatic or should I alter my current one. I still want good off-road but want a little more performance.

If you suggest a new gearbox, which one should I get, if I stick with the current one, what upgrades should I use?

If you have any hints or tips, please let me know!!

Thanks
J
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defender50th
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Joined: 14 Nov 2004
Posts: 1520
Location: Hampshire

PostPosted: Sun Feb 26, 2006 6:24 pm    Post subject: Reply with quote

Hi there,

The problem with the poor performance on a 50th is the transfer box rather than the gearbox, as it is geared to the american market. So if you want to improve performace you should have the ratios changed in the transfer box from 1:222 to 1:410. If you speak to Ashcroft transmitions then they will help : http://www.ashcroft-transmissions.co.uk/

What plaque number is your 50th, can i put you on the register,

Hope this helps

Best regards

James
GB 002
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novice_mechanic_1
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PostPosted: Thu Mar 02, 2006 9:33 pm    Post subject: Reply with quote

Thanks James,

Have not finished completing the purchase of mine, planning ahead if you see what I mean Wink

Will let you know!

J
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SteveT



Joined: 04 Mar 2006
Posts: 64
Location: Enfield

PostPosted: Fri Mar 24, 2006 8:32 pm    Post subject: Transfer ratios Reply with quote

Evn'g all.... The change of transfer drive ratios IS the way to go. I've just got my 50 back today (Ashcroft did it) and what a difference whoooosh! Well perhaps not quite but its a lot more nippy than before almost like my Disco. The 1:1:410 ratio does give it the ability to move off a darn sight quicker and to zip up to speed, but watch out for lorry drivers that THINK you are still a slow old plodder, had one pull out in front of me.
Also just out of interest, as the 50 was new to me, had it checked out at the same time and the viscous coupling to the cooling fan had stuck itself soild, which accounted for the increased rev noise (I thought it sounded good, my wife on the other hand had the pleasure of telling me she was right and that there was a fault!) and some of the power drain I'm told.
Still - recommend the ratio upgrade, drives so much better.
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tractionman



Joined: 16 Oct 2005
Posts: 85
Location: Gloucestershire

PostPosted: Sat Mar 25, 2006 11:57 am    Post subject: Reply with quote

Does the auto box now change gear at lower road speeds?

The reason I ask is I would like the torque converter to go into 'lock up' mode at a lower road speed. Currently mine locks up at about 57MPH (you notice a drop in revs as it locks up and the torque converter is effectively bypassed). Most of my miles are on country roads doing about 50 and I'm sure it would be more efficient if the torque converter is out of the equation.

I think, Going from 1.2 to 1.4 should, if the auto box uses engine speed not road speed, mean the lock up occurs at about 49MPH.

Any thoughts?
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ex GB001 owner (Gone back to previous owner)
ex GB236 owner
ex GB353 owner
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Ads90



Joined: 02 Feb 2005
Posts: 290
Location: Gloucestershire

PostPosted: Mon Mar 27, 2006 8:41 am    Post subject: Reply with quote

I think the auto 'box is left unaltered, in whick case it should lock-up at a lower speed, which would be good for my roads too.

Mine locks at an indicated 55mph - the ratio change drops the speed by 13.3%, so it should then lock at 48mph, not a huge difference, but may just help efficiency a little on those country A/B roads!
Also it currently shows 2500rpm @75mph, following the same calc the revs would only increase to 2700rpm - not too bad there either.
(It's on my very long 'to-do' list also).

James or Steve would be able to confirm this...
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SteveT



Joined: 04 Mar 2006
Posts: 64
Location: Enfield

PostPosted: Mon Mar 27, 2006 11:25 am    Post subject: Ratios and revs Reply with quote

Could not answer your question until now, but after a good run up to Cambridge on Sunday using the A10 / A14 and M11, I can provide the following information and would like feedback from others on the data (i.e. if you have had your ratios changed does it ring true). I have YET to have the Sagem re-chipped and that might make a difference? What I do have might answer your question on engine revs (or not - lol!)

I found that up to 30mph the revs were a constant 1,500. Then between 30 and 50 mph the revs went up quickly to 2,000. At around 50mph there was a distinct change in engine noise, it changed to a lower pitch, but the revs remained at 2,000. Depending how I treated the accelerator - harsh pushed the revs up to 2,500 at 60mph but then remained nudging 2,600 at 70mph. If I was gentle, then the revs remained at 2,000 at 60mph but then increased in proportion to the speed, you could see the revs and the mph move up together.

So? Does that ring true with others that have already had their ratios changed - I would think I'm only half way there at present and that having the re-chipping done is the next step to complete the modification. I strikes me that the Sagem control needs to 'know' that the ratios have changed otherwise the increased transfer power is not fully being recognised and implemented by the Sagem control - any thoughs?
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GEO
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PostPosted: Mon Mar 27, 2006 12:37 pm    Post subject: Ashcroft Transmissions Upgrade Reply with quote

How much did the Ashcroft upgrade set you back Steve, and what was involved.

How long did they require the car, etc.

Thanks

GEO
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defender50th
Site Admin


Joined: 14 Nov 2004
Posts: 1520
Location: Hampshire

PostPosted: Mon Mar 27, 2006 8:32 pm    Post subject: Reply with quote

Hi Steve,

Yeah all sounds right Steve. My ratio change was done in a different way. The origonal tranfer box was removed and a bourg warner chain drive one used, as used on the range rover. I cant quite remember what mine revs at at motorway speeds.

I would call Mark Adams about the chip and he can tell you the changes you might expect.

Best regards

James
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