Sierra dif info please!

[carefull]

Hi there, I have been on the look out for a 3.92 LSD sierra diff for ages now. I finally found a guy breaking a sierra 2.0 xr4x4 so I purchased the dif which I thought was the exact same dif. Now my problems start, I want to fit it in my Caterham Roadsport but the caterhams come with push in drive shafts and the diff I bought has bolt on flanges. Can I change the fitting method or are there two different diffs? or does the 3.92 7" LSD diff only come with flanges??

Jason

[stevieturbo]

AFAIK, only the old drum brake cars had push in shafts.

Which means virtually none of them came with an LSD as standard, apart from maybe the original XR4i, but it wont be a 3.92

Might be worth asking on some kit car or caterham forums ? with direct experience of such things.

[dern]

Have a search on locost builders as there are more threads on there regarding the difference between sierra diffs and the application of them than you'd believe.

[Mr2Mike]

You can not convert an LSD to use the push-in driveshafts, there is simply not room inside the diff.

However, you can create a hybrid drivesgaft with normal CV's on the outher end for drum brakes, and Lobro joints on the inner to bolt to the LSD flanges. As said, loads of threads about this on Locostbuilders

[carefull]

Thanks guys,I have just been reading the Locst thread and someone has posted a fact sheet of what he has lernt about the sierra diff minefield and he has posted pics of LSD drive flanges removed from the diff. They are shown with splines on and I recon that Caterham's splined drive shafts may replace these flanges???

Jason

[FlatPack]

Mr2Mike said:

you can create a hybrid drivesgaft with normal CV's on the outher end for drum brakes, and Lobro joints on the inner to bolt to the LSD flanges.

I've done this and it wasn't as straightforward as some people make out (I can only assume they stumbled across the right driveshafts straight away). There are at least 3 different Sierra driveshafts that have the push in type joints as standard, each has a different number of splines on the end of the shaft. Two of them are externally identical and you can only fit a lobro joint to one of those two. I couldn't find a set that would 'work' and as I needed the shafts shortening to fit my Striker anyway, I just got a custom set made up that could take my push in joints on one end and lobro ones on the other. Works fine now though

[FlatPack]

carefull said:

Thanks guys,I have just been reading the Locst thread and someone has posted a fact sheet of what he has lernt about the sierra diff minefield and he has posted pics of LSD drive flanges removed from the diff. They are shown with splines on and I recon that Caterham's splined drive shafts may replace these flanges???

Possible, but the output flanges are different for an open diff with lobro joints and an LSD. They're shorter on one side for the LSD to give more room in the diff casing for the LSD gubbins. You can remove the flanges from an open diff and use push in joints directly into the casing, but not with an LSD.

[carefull]

stevieturbo said:

Might be worth asking on some kit car or caterham forums ? with direct experience of such things.

I did post on the Caterham forum but the mods must have moved it to here.

I just checked what my current roadsport has and its a LSD diff without flanges and with caterham push in shafts so I'm even more convinced that I just might have the right diff here for my new Roadsport.

jason

Edited by carefull on Friday 13th July 00:37

Edited by carefull on Friday 13th July 00:38

[ELAN+2]

IIRC, series one sierras had push in drive shafts, late series two's had the flange type, certainly all the twincam and 2.9 4x4s i broke had flanged efforts