overdrive vs rr diffs

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ffourphantomfixer

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  • Name: Andrew Forrest
overdrive vs rr diffs
« on: July 20, 2010, 03:50:49 PM »
Whilst im on and before I go to bed...

What are the pro's and cons of converting my series 3 88 to overdrive (assuming I can find a good complete unit) or just changing the diffs to rrc.

I would like to cruise at 60 but would also like to try a few rtv trials.

What do you guys think / advise

Cheers.

Drew.
She said at my age I need something else to play with

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philbert

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Re: overdrive vs rr diffs
« Reply #1 on: July 21, 2010, 07:33:20 AM »
depends on a lot of things but mainly what engine you have and the condition of it!
you will have a gearing raise of 25% with the rr difs which is a lot with a tired engine.
overdrive is the way to go if you can find a good one.

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lreay

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Re: overdrive vs rr diffs
« Reply #2 on: July 21, 2010, 12:49:46 PM »
Drew,

The overdrive will give you more options, but as another alternative you could up the transfer box gearing for high range for cruising and leave low alone for RTVs.

http://www.ashcroft-transmissions.co.uk/index.php?act=viewProd&productId=43

Cheers
Luke

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Truckster

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Re: overdrive vs rr diffs
« Reply #3 on: July 21, 2010, 04:14:43 PM »
Ive overdrive on my diesel 109 SW. Lowers the engine revs for daily driving, and i use it like a 5th gear. :)
Mel ( & canine navigators )
109 Station Wagon-'The Goddess'- Sick Chassis...gutted!!
109 Station Wagon-'Firefly'-in need of tlc!!!
109 Ex-mil Rolling Chassis
Mk5 Blue Oval ( Goddess in training!!)

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Lwtman

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Re: overdrive vs rr diffs
« Reply #4 on: July 21, 2010, 08:58:23 PM »
Just in case you have 'small' tyres, another option may be changing tyre sizes. What tyres do you have on your 88? If you have 6.50 (or 205) you could fit larger tyres 7.50 (or 235's) which will up your gearing and still be a standard LR S3, they were both fitted to SWB I think. The increase is about 8% as I remember. Note. The speedo will need changed though.

Regards

Peter

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jumbo

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Re: overdrive vs rr diffs
« Reply #5 on: July 22, 2010, 08:28:24 AM »
got 235/85's on my 90 and makes a big diference to clearance. i dont have dif guards and being honest ive never heard them contact before.
i trundled through ruts, look back to find discos with 235/70 sitting high n dry on thier difs.
doug
2005 3door freelander td4
1986 90s/w with 200tdi


warning::: any jokes posted by myself come with a health warning!!!!!

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ffourphantomfixer

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Re: overdrive vs rr diffs
« Reply #6 on: July 23, 2010, 06:23:31 PM »
Thanks for the reply's folks.  I do intend using the S2a/3/90 regularly all year, also I would like to try some off road driving but at the moment im just working towards getting it rebuilt and through an mot.
I have 235/85/16 fitted to 8 spoke 8x16 I also have a set of modular 7x16 incase the tyres stick out, I dont want to fit defender arches.

To update my progress, The chassis is now finnished and painted, new brake lines, shocks, springs, drums and shoes fitted, both rear drive flange seals replaced, new rear prop fitted, axle breathers fitted, the rear tub is undersealed and the galvy cappings removed and painted, once the tub has been primed and painted it will be fitted so i can line up the s3 bulkhead with the doors closed to check the fit of the doors and floor pannels against the bulkhead. I had no real option but buy a S3 bulkhead as there were no S2a available when I had the cash. Im fitting a 90/defender front end as I was given a complete 19J engine with radiator which has the integrated oil cooler so the 90 front end seems easy and sensible.

I have still to sort out the front swivels which are pitted and leak badly, im considering powder coating them but have not yet done anything about it as I need to keep the chassis rolling.

So its a Series 2a with a S3 bulkhead and interior and a 90 front end and at this moment I have absolutely no idea if it will all line up when the time comes to try. I can imagine what the purists are thinking  :-[

Again many thanks for the reply to this and the other posts.
She said at my age I need something else to play with