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        General >> Give/Need advice to/from others >> Diff ratios
        
(Message started by: mijfife on Nov 8^th, 2008, 12:32pm)

Title: Diff ratios
Post by mijfife on Nov 8^th, 2008, 12:32pm

Hi all, I'm trying to find out the different ratios on the diffs in the Scorpio range, in particular, the 2.9 12v and the 2.5Td. I'm sure I've seen the info on here somewhere but just cant find it at the moment, can anyone put me out of my misery? ;) My mate mentioned that the diff code is on the vin plate but couldn't remember which letters applied to it.

Cheers Jim

Title: Re: Diff ratios
Post by Simmo on Nov 8^th, 2008, 12:37pm

Jim, Is THIS (http://www.fordscorpio.co.uk/manual/rearaxle/RAxleSpecs.pdf) what you are looking for??. ;)

Your mate is right and the detail is HERE (http://www.fordscorpio.co.uk/vin.htm) ;D

Title: Re: Diff ratios
Post by Highlander on Nov 8^th, 2008, 6:47pm

Diff ratio for the 2.3 is wrong on that spec sheet, its actually 3.91

Title: Re: Diff ratios
Post by mijfife on Nov 8^th, 2008, 7:01pm

Thanks Simmo, that was exactly what I was looking for, just couldn't find it ;) The reason I'm asking is that I suspect the diff on the 2.5 TD is about to go bang. yesterday, it made a funny noise and kept feeling like something was trying to hold the car back. I checked things like wheel bearinga and drive shafts but they all felt fine.
I've got a 2.9 12v auto that I'm breaking and wondered if the diff was the same. The Td has a diff ratio 3,64 and the 2.9 has 3,36. I'm not very good at understanding ratios so could someone explain in easy terms what difference would it make to the TD by fitting the 2.9's diff?
Cheers Jim

Title: Re: Diff ratios
Post by Highlander on Nov 8^th, 2008, 7:58pm

you'd accelerate slightly quicker,
the revs would sit slightly higher with the 2.9 diff at the same speed so on a motorway run you'd get slightly less mpg. although you're only talking about 8% difference.

If you liken it to a pushbike, your diesel diff is like you starting off in second gear, a 2.9 diff would be like you starting off in first.

You're speedo will show 8% faster too unless you use the 2.9 drive pinion for the VSS (Vehicle speed sensor) on the gearbox

I'd replace it with the 2.9, diesels diffs are quite rare and expensive, the ratio is sought after for kit car cars, race cars etc

Title: Re: Diff ratios
Post by mijfife on Nov 8^th, 2008, 8:32pm

Thanks again Highlander, Since I run on veg, the fuel drop won't be an issue anyway, as you well know!
I've got a bit of welding to do on the rear chassis rails for the mot, so I might just drop the entire rear subframe and replace the lot from the spares car. It's only done 90k without a towbar compared to the TD's 152k
Looks like I'm gonna be busy next week again ::)

Cheers Jim

Title: Re: Diff ratios
Post by mijfife on Nov 9^th, 2008, 11:55pm

It looks like I won't have to swap the diff after all :) The rear wheel bearing collapsed tonight so I guess that's what the problem was!! I'd checked both bearings as soon as I first had problems but both felt fine with no play and no typical worn bearing whine, never had one go like that before ???

Cheers Jim

Title: Re: Diff ratios
Post by Simmo on Nov 10^th, 2008, 6:59am

It does happen Jim!!. Trust you and the car are OK as there have been one or two disasters when this has happened. It usually means the hub will need replacing as it is probably damaged. ;) Mike

Snoopy has provided THIS article (http://www.fordscorpio.co.uk/rhubs.htm) which explains all.

Title: Re: Diff ratios
Post by mijfife on Nov 10^th, 2008, 10:08am

Hi Simmo, I was only a few miles from home when it finally went so I just crawled down the road at 15mph! Some lovely noises, I can tell you ::) I'm planning to just use the complete hub assembly from the spares car, no point buying a bearing when there's one sitting and I think you'll be right about the damage to the existing hub! Thanks for the link to Snoopy's article, it goes into a bit more detail than the bit on the axle manual and will a big help.
Right, where are my overalls (again >:()

Cheers Jim

Title: Re: Diff ratios
Post by Highlander on Nov 10^th, 2008, 9:25pm

on 11/09/08 at 23:55:34, mijfife wrote:

I'd checked both bearings as soon as I first had problems but both felt fine with no play and no typical worn bearing whine, never had one go like that before

Did you check them with the wheel jacked up Jim?
You cant check them with the wheel on the ground, it wont show any signs unless the weights off it

Title: Re: Diff ratios
Post by Highlander on Nov 18^th, 2008, 9:22pm

on 11/08/08 at 19:58:05, Highlander wrote:

diesels diffs are quite rare and expensive, the ratio is sought after for kit car cars, race cars etc

Heres two on ebay now, both diffs have been removed from Scorpio diesels ;)

If you're scrapping a diesel KEEP THE DIFF!! ;)

http://cgi.ebay.co.uk/ford-7-5-cosworth-24v-diff-3-36-RARE-ratio-KIT-CAR-etc_W0QQitemZ160298688924QQcmdZViewItem?hash=item160298688924&_trksid=p3286.c0.m14&_trkparms=72%3A1121|66%3A2|65%3A12|39%3A1|240%3A1318

http://cgi.ebay.co.uk/SIERRA-3-36-REAR-DIFF-KITCAR-MK-WESTIELD-LOCOST-7-5INCH_W0QQitemZ160243555736QQcmdZViewItemQQptZUK_CarsParts_Vehicles_CarParts_SM?hash=item160243555736&_trksid=p3286.c0.m14&_trkparms=72%3A1121|66%3A2|65%3A12|39%3A1|240%3A1318

Title: Re: Diff ratios
Post by mijfife on Nov 18^th, 2008, 11:28pm

Hi Highlander, yes I'd checked it with the car off the ground, no play, no roughness, I've certainly never experienced a wheel bearing go like that before
??? Fortunately the spares car yielded a good one so a nice easy hub change and I was sorted :)
I see what you mean about the diesel diffs being rare, that's a lot of dosh they're asking :o

Cheers Jim