Whining Rear Diff / Repair or Upgrade..

[Rizy247]

Hi guys , I just acquired a 320i manual 2dr with a VERY loud whining diff at all speeds.

Was told by the previous owner "I just need to buy a diff rebuild kit" now looking around what exactly is a diff rebuild kit :/ costs etc .

I'm wondering bother to even source a rebuild kit or just buy a recon rear diff or put in an upgraded LSD?

I want fast acceleration, I don't want to slow it down more .. I don't drift well on purpose anyway and I don't race.

Just a cruiser..

Thinking if it's money going into it rather get something better.

I'm in London so would need someone round here to do the works /supply

Whats your thoughts

It's a G reg manual 320i coupe

Thanks

[DanThe]

Rebuilding an open small case diff is pointless, buy another one or upgrade to a medium case diff or LSD

[Rizy247]

Do you know what exactly I am in need of if I go for an LSD that won't compromise speed of the car

Major confused with all this gear ratio stuff.

And thanks for the speedy reply

[flybynite]

Major confused with all this gear ratio stuff.

have a read of the Wiki........... always a good place to start

https://www.e30zone.net/e30wiki/index.p ... fferential

[Rizy247]

Ile be honest with you that's the thread I read before I posted when I saw the calculator page it reminded me of doing my GCSE's brought back all the anxiety :/ lol

Man just don't want to regret doing it

My thoughts are get an LSD 3.73 or 3.91 but scared the 3.73 will make the acceleration worker then it is now

[Lemon98]

Do you know what ratio you have in currently? Possibly a 4.10?

A 3.73 will make the acceleration worse for sure. I have a 320i saloon with a 4.10 diff (also noisy and clunky) but I don't want to buy a medium case LSD because I'll lose the ratio and love how the car cruises and responds with the diff and engine combo. A 2nd hand E30 LSD will most likely need rebuilding anyway to work properly because it's just as old as what you have already!! The clutch plates will be worn out at the least, making it ineffective at actually locking the wheels.

If you're just using it for cruising and don't plan on increasing the power much then rebuilding your current diff should be fine. From my research this is the sort of kit that you should need https://www.bearingkits.co.uk/BMW-3-Ser ... it/992.htm.

My choice is to save up for a mechanical LSD centre that fits into the small case diff so I can keep the 4.1 ratio but this is expensive https://www.regalautosport.com/shop/Wav ... Axles.html

[ChrisHC]

First of all I would check the oil level in the diff to make sure the problem is not something as simple as that. If you are simply intending to use the car for cruising, there is little point in paying for an LSD. The standard ratios BMW choose for the 320i are likely to be the best compromise between acceleration and relaxed motorway driving, I would stick to those.

[Rizy247]

Based on the above if I did stick to the 4.10 I've found somebody who is selling a refurbished diff for £330 on an exchange basis (give my old)

What's the views if this is worth it rather than spending £130 on a rebuild kit then another £150 or so for fitting /service on the old one..

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[ChrisHC]

That sounds genuine but it would be good to hear from someone who has dealt with the firm if you do not know them, there are "reconditioners" out there who do little more than clean the outside and spray black paint on the item.

[DanThe]

A 4.1 medium case LSD will cost the best part of £700-£800 nowadays, a good used 4.1 small case open diff can be had for anywhere between £50 and £150, if the pictures above are anything to go by then they are not E30 diffs