Discussion
I have a very noisy (standard) diff in my '07 reg 125 sigma roadsport and have decided it's time to do something about it, but what? Top of my options is to take it out myself then take it somewhere to be reconditioned. But is this the best option? I know there have been several issues with diffs in this age of car so if anyone else has had personal experience of this problem do you know what type of diff (ratio) it is and what exactly does go wrong with them? What is the best way of solving the problem? Is it a DIY job or is it definitely best left to the professionals? I know whenever a similar question has been asked before the answer usually seems to be "Road & Race", but I really don't want to have to drive all the way to Kent so does anyone know an equally reputable firm within about 30 miles of Newbury (Berks) that would be able to do the job? What sort of cost should I be looking at? How much extra would it cost to swap it for a recon LSD?
All help/suggestions/contributions gratefully received!
Thanks
NGee
All help/suggestions/contributions gratefully received!
Thanks
NGee
Firstly most diffs will make some noise and a noisey diff does not mean it is about to fail - in fact a healthy wine that comes and goes at different speeds suggest a good contact patch. It's really down to your own tolerance to the noise.
Early diffs from the Ford factory can be quiet but Ford went to unbelievable lengths in quality control to achieve that so it is unlikely a re-manufactured unit will be anything like as good - the recent Caterham diffs are a good example of how difficult it is to make a quiet one.
Good that Road and Race are, they can only achieve what the parts allow, so don't expect a 100,000 mile diff to be as quiet as it was when new. If you do it yourself (and it is not that difficult) you can play around and make them quieter but this is often at the expense of a good contact patch - but that may not be important to you.
[Edit: a 2007 car will not have a 'genuine' Ford crownwheel and pinion so don't expect having it overhauled will solve the noise problem. Finding an original Ford diff may be the best option.]
Good luck.
Early diffs from the Ford factory can be quiet but Ford went to unbelievable lengths in quality control to achieve that so it is unlikely a re-manufactured unit will be anything like as good - the recent Caterham diffs are a good example of how difficult it is to make a quiet one.
Good that Road and Race are, they can only achieve what the parts allow, so don't expect a 100,000 mile diff to be as quiet as it was when new. If you do it yourself (and it is not that difficult) you can play around and make them quieter but this is often at the expense of a good contact patch - but that may not be important to you.
[Edit: a 2007 car will not have a 'genuine' Ford crownwheel and pinion so don't expect having it overhauled will solve the noise problem. Finding an original Ford diff may be the best option.]
Good luck.
Edited by DCL on Monday 17th October 19:49
I wouldn't get too worked up by it. That very same diff used in the back of a Sierra would have been tucked away under a boot surrounded by anti-vibe and noise absorption pads. You wouldn't hear the whine. Also your 500 kg Caterham would create less wear and tear than the 1500 kg Ford jelly mould that diff came out of. It'll last forever.
Good advice there 
Some people say that a well worn in crown wheel and pinion from a high mileage diff will mesh really well once rebuilt.
I bought an old diff from ebay, and had Road and Race rebuild it with a new Titan LSD and it cost about a thousand all in
The other option is a replacement BMW diff from Caterham, but that is over a thousand just for an open diff, and I have heard that the bearing design on the BMW diff isn't as well engineered as the Ford one!
Some people say that a well worn in crown wheel and pinion from a high mileage diff will mesh really well once rebuilt.
I bought an old diff from ebay, and had Road and Race rebuild it with a new Titan LSD and it cost about a thousand all in
The other option is a replacement BMW diff from Caterham, but that is over a thousand just for an open diff, and I have heard that the bearing design on the BMW diff isn't as well engineered as the Ford one!
The BMW diff uses double row tandem ball bearings, instead of the tapered bearings in the Ford diff.
These ball bearings need a perfect setup (preload) otherwise they may suffer and fail prematurely.
On the other hand they generate less heat, need less oil, and have the benefit of decreased friction: A lot of things that are good in a modern BMW but useless in a 7....
That said, my 2010 R300 received under warranty a BMW diff with the upgraded carbon plates, instead of the 2 previous noisy Ford diffs with Quaife ATB I had before. In opposition to the initial BMW diffs with sintered plates, the carbon plates one are completely silent in turns or parking drive. There was also a slight improvement in noise when decelerating in 5 or 6th gear, compared to the FORD diffs I had, but it's not a world of difference. I was really expecting more benefit on this point. Furthermore the BMW diff is making clongs at gear changes, it has a lot of free play.
So my advice would be also to buy an old FORD sierra diff with genuine FORD crown wheel and pinion and let it refresh at Road and Race.
PS: Some FORD diffs on new 7's in the last year are horribly noisy (I had 2 of them !), it has nothing to do with just a lack of carpeting: They are really bad and would also be noisy in a Sierra...
These ball bearings need a perfect setup (preload) otherwise they may suffer and fail prematurely.
On the other hand they generate less heat, need less oil, and have the benefit of decreased friction: A lot of things that are good in a modern BMW but useless in a 7....
That said, my 2010 R300 received under warranty a BMW diff with the upgraded carbon plates, instead of the 2 previous noisy Ford diffs with Quaife ATB I had before. In opposition to the initial BMW diffs with sintered plates, the carbon plates one are completely silent in turns or parking drive. There was also a slight improvement in noise when decelerating in 5 or 6th gear, compared to the FORD diffs I had, but it's not a world of difference. I was really expecting more benefit on this point. Furthermore the BMW diff is making clongs at gear changes, it has a lot of free play.
So my advice would be also to buy an old FORD sierra diff with genuine FORD crown wheel and pinion and let it refresh at Road and Race.
PS: Some FORD diffs on new 7's in the last year are horribly noisy (I had 2 of them !), it has nothing to do with just a lack of carpeting: They are really bad and would also be noisy in a Sierra...
Edited by PINGUY on Wednesday 26th October 22:07
DCL said:
Early diffs from the Ford factory can be quiet but Ford went to unbelievable lengths in quality control to achieve that
This is spot on. In an attempt to figure out why some diffs are noisy and some are not I have done lots of digging recently to find out exactly how they were set-up by Ford. The original Ford manual I have here makes good reading and speaks of a shim pack that is used to set the exact height of the pinion and it is stressed that this is very important. The reason why is if the pinion is too low, when you have crown wheel and pinion meshing with the correct large contact patch central in the tooth then the backlash will be too large and vice versa. I spoke to two diff rebuilders and none of them used these shims and one never knew they existed.. As far as I can see, it is simply potluck if you get a good one. In an attempt to get a decent one I found a sierra diff that had a good pinion preload because to get the pinion in and out you really do need the proper tools and I haven't. The rest of the job is easy enough to do. My theory was that if the Ford set preload was still there then the pinion height would be right too. So again in theory all I had to do was set the mesh right and it would be back to how it left the factory. While apart I fitted a ZF slipper, new bearings where I could and new seals. It's much much better than the other one I have here and I can live with it until I find that illusive new in box one I have been searching for...
If anyone wants the PDF sending over for the Ford diff rebuild guide let me know.
Jason
Edited by Purespeed on Wednesday 19th October 23:28
Have the same problem with our 125 Roadsport which is now at 21k miles. Love the car apart from that and it stops whining at about 55mph. Going for a rebuild this off season as in talking with Nick at Midlands he couldn't guarantee a refrub or replacement would be any better. I find him very straight talking so we'll have a play and see if we can do a bit better. Best of luck.
PINGUY said:
In opposition to the initial BMW diffs with sintered plates, the carbon plates one are completely silent in turns or parking drive. There was also a slight improvement in noise when decelerating in 5 or 6th gear, compared to the FORD diffs I had, but it's not a world of difference. I was really expecting more benefit on this point. Furthermore the BMW diff is making clongs at gear changes, it has a lot of free play.
I've found very similar with mine, the 1st BMW diff was replaced under warranty, not because I was expecting a Caterham to be quiet, but because the diff whine at anything above 50mph was so intense it was painful. Coupled with the clunking and banging with any lock applied, it spoiled the drive. The carbon plated diff now fitted certainly isn't quiet ( I wouldn't expect it to be) but it is much better and, as with the above post, mine is quiet on lock now. Similar findings with gear changes, noticeable free play and clunks when a gear engages . I have found that in the 1200 or so miles I've done since the original diff was changed, the new one has become a bit quieter than it was when new, so definately worth changing.Agree with the suggestion of doing it yourself - the oldtime skills are hard to find and plenty of saddo's out there doing a crap job at other peoples expense. {no names mentioned, but I know plenty]
My suggestion is to use the diff until it cries 'enough'. This may never happen, it depends on your idea of how loud a diff ought to be, all diffs give off some Mechanical whining noises.
A potential cure is to fit a SCCR gearbox - you'll never hear the diff if you do that
My suggestion is to use the diff until it cries 'enough'. This may never happen, it depends on your idea of how loud a diff ought to be, all diffs give off some Mechanical whining noises.
A potential cure is to fit a SCCR gearbox - you'll never hear the diff if you do that
I blew the diff out of my CSR260 at Oulton park doing a trackday on sticky tyres , I snapped the casing which im told is common with the grip levels of a csr ,anyway I got the diff rebuilt and soon as i put it in it appeared to be much noisier, I removed and resent the diff back to be checked and was rebuilt again and when refitted was just as noisy, thinking back now at the same time I fitted the recon diff i also fitted the diff support stays from caterham, Ive been thinking now that they prob increased the noise as they fasten to the diff and are bolted under the seat belt anchors just behind you lugs,Im pretty sure thats what made that car so loud, it was quiet under load no whining and fine off the throttle but very clunky when at cruising speed , I wont be fitting them to my current car.
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