Went for my first drive today and my diff is shot. It clunks and bangs all over the place so looks like i need a new one. I can get the same diff but with a LSD and i'm thinking i may aswell get it checked/rebuilt before i put it in just to be sure. I was just wondering roughly how much i should be charged for this sort of thing?

FIRST drive? as in you've never driven it before? have you driven any BEC before?
BECs do make a lot of banging and cluncking. no, i'm not building one, I have driven one in the past though
best to let someone else who has built/driven one to have a shot before writing it off completely i'd say
i can see your reasons for worrying, as you want a LSD, and rightly so but it might not be all bad

i can't remember what i paid for my open diff to be rebuilt a couple of years back, must have been £100 plus parts plus vat maybe?

[Edited on 4/4/12 by blakep82]

Yes first drive as in i have never driven it before. I did have my doubts about the diff when i fitted it but this has confirmed it. I know i'm not used to driving a bec but it sounds pretty knackered to me.

It will clank and rattle in a BEC, you need to drive around for a bit and practice gear changes before committing.

I made 2 out of 1 when I put my LSD into 3.14 diff and did it up tight and it still clanks if I am clumsy.

I paid £250 for the 3.14, the LSD came with the sierra but are around £150 now I guess for a Viscous 3.65 diff.

Bearings to rebuild will be £60 then its labour so I would guess £150 to build two into one would be cheap.

Regards Mark

A1 Gearboxes in Eaton Socon might be worth a ring , just up the A1 from you

I actually rang them ages ago when i got the original diff as i wasn't sure on it's condition. IIRC they weren't very helpful and quoted me something like £500 to rebuild it but didn't seem to want to do it at all. I rang A1 premier transmissions (i thought they were the same as A1 gearboxes) today but have to ring back tomorrow to have a chat with the diff guy. They sounded alot more friendly than A1 gearboxes. Just wanted rough costs so i could compare tomorrow.

I've always found A1 gearboxes to be very helpful , if you ring again ask for Steve, he's the boss .

Someone posted a link to a site that had instructions on how to do the job , might be worth a search ? ISTR Rallydesign may do recon Sierra diffs ? Not sure of the price though

I did the same as Mark turned a 3.14 into a LSD they arn't difficult to work on, i set my backlash a bit looser as i think that's better than too tight, mine clunks.
even if i bought a brand new diff it would still clunk it's just a BEC trait

I got quoted £250 to replace the bearings, set it up and clean it. It was kind of implied that £250 would be a minimum and it could be far more depending if any parts need replacing. I think I may just put the lsd one in and see how I go.

[Edited on 5/4/12 by Davegtst]