The way to a quieter diff

[sevenmad]

The 3.62 Quaife sierra diff which came with my 2010 Roadsport has always been an annoyance. It has had a persistant high pitched whine between 40 and 60mph and moderate backlash. I took it to R&R who had a go at it, and made it slightly better, but the whine persisted. It ruined what was otherwise a great car. I tried filling it with all sorts of different snake oil, some of which produced a short lived improvement, but it always ended up being really annoying.

I started toying with the idea of forking out £2000 for the BMW diff as the only way to sort the problem. 1 was kicking myself for not taking Caterham up on their offer of a swap to the BMW unit at reduced price.

As a last ditch effort I bought an old original Ford 3.92 off ebay for £20. It was dirty as hell, but had come out of a sierra with only 65000 miles on the clock. I thought about giving it to R&R to set up but it felt good so I cleaned it up and gave it a lick of aluminium paint. Bought some new oil seals off ebay for £18 and swapped them out, and then swapped it out for the Quaife 3.62.

Amazement!! This diff is a revelation. There's no backlash, no grinding of cogs, and minimal whine between 55 and 60 ( at about 1/4 the previous volume). I suddenly appreciate what a great engine note the sigma has when you can hear it.

It makes you realise that this unit can be quiet. It just needs to have the original internals not reconditioned parts! It can also be quiet in a metric chassis. As an added bonus the 3.92 seems better suited to the car, it makes it feel slightly more lively,

All in all about £50 well spent.

[10 foot]

I too have a 2010 Roadsport (though have paid CC to do Supersport upgrade to it). My diff is very quiet though, I've never had noise issues luckily. My dilemma is whether to fork out for a LSD,- as on recent trackdays I had problems with power spinning away on inside wheel on hairpins. But I'm worried if i go LSD I may end up with a howling diff which is the last thing I want.

[DJ.]

I went the ebay 3.92 diff route, but got R&R to rebuild it with a titan LSD.

 

It cost me about the same as the special offer BMW, but I got a free LSD

 

There is now no noticeable backlash and much reduced whine, so I'm very pleased.

 

The old Ford Sierra diff (mileage unknown!) has a lot less metal particles in the oil than my new diff did after 500 miles

 

Duncan

[Mankee]

If you are retaining your current CWP and only swapping out the open diff for an LSD, then it won't make any difference at all to the amount of whining (or not) as long as you set the backlash up properly. All the old OEM Ford diffs seem to be a lot less problematic in terms of noise than newer pattern parts which haven't been made as well.

[The Pikey]

I think Caterham used pattern CW&P for only a short period. They were crap so they went back to using second hand Ford parts. I have only seen one Pattern CW&P and it had deep wear after a very small amount of miles. On my current diff I have set the backlash to 2 thou and I am 100% sure this is the way to go because it's perfect. Like Sevenmad's diff mine was also bought from Ebay for a small amount of money and this is why I now have 11 of them under the bench at work

[DJ.]

Quoting Jason Fletcher: 

Like Sevenmad's diff mine was also bought from Ebay for a small amount of money and this is why I now have 11 of them under the bench at work

 

Now that's just greedy 😬

 

Thanks for your advice while I was deciding to get mine sorted.

 

Duncan

[The Pikey]

We according to the stats there were 6077 Sierra's Taxed and 8010 went on SORN this year so there is still plenty to go at

 

Jason

[Dave Allen]

Roll up Roll up.

 

Get your diffs while stocks last. 😬

 

Edited by - Dave Allen on 9 Sep 2012 22:04:36

[anthonym]

hmmm.. I've got a "complete 3.62 diff with LSD in housing" I don't know what to do with.

[Graham Perry]

I have a 5000 mile original Ford supplied 3.92 under my bench as well, just in case I ever want to go touring as the normal 4.44 would be a bit short legged. I got it from a Sierra total write-off at a local scrapyard about 15 years ago.

[MarkHyde]

We have a 2010 (Dec) R300 which we were told by the salesman at CC would have the new BMW diff (LSD) fitted when we ordered it in June 2010. It was built with the Sierra diff! I was not happy as one week after taking delivery of the car I received a letter offering me the 'upgrade' to the BMW diff at the offer price! I complained but was assured that the Sierra diff would be fine. How wrong can you be, the diff was unbelievably noisy, for me it totally ruined the driving experience, like listening to a box of spanners being dragged under the car at 50-60 mph and particularly on lift off. Complained to CC and another two diffs were fitted, all were as bad as the first (agreed by CC) We had lost weeks of being able to drive the car in our first summer, complained again and eventually CC agreed to fit the BMW diff, free of charge, a great result, but another 5 weeks off the road. The BMW diff is still noisy but there is virtually no whine and the lash has been reduced by 80%. My point is, if other manufacturers/specialists can get it right then CC should be getting it right first time, this was after all a £37,000 car. The moral of the story? if it's not right complain, I've said it before on this forum, it's the only way things will improve! I don't believe that you should be looking to specialists etc to improve the enjoyment of your 2010 car. Best of luck, Mark H.