Are there different S14 spline/halfshaft sizes?
I currently have my car in bits at a gearbox specialist who are telling me the Viscous unit they have just fitted (from Phatty's old S14a) has totally different sized splines to the S14 one they've taken out so the shafts don't fit, they're just spinning.... WTF?????
help
Never heard of it, but Ive never cracked the S14 or S14 a diffs open!
I dont suppose the S14 diff was an auto diff? That may explain it...perhaps
Originally Posted by TAS
I thought Matt_S invented SXOC
Just had a look on the manual pdf and it doesnt mention anything as being different with the output shafts...
The only differences listed are the number of teeth on the crown wheel and therefore the gearing is different (which we new anyway!)
You could ring up Nissan and ask if there is a different part number for M/T and A/T output shafts...
This is all assuming that the problem is with the S14 diff being an Auto diff though I must add.
Also, just checked between S14 and S14a supliment and there is no section for the diff, which maens that they are the same from S14 to S14a
I thought Matt_S invented SXOC
there was 2 different diffs, one for 94-96 and one for 96 on on bothe the MT and AT but the latter is an alternative for the former so i would imagine the splines must be the same to be compatable.
MT Part Numbers
-96 38301-21Z70
96- 38301-21Z78
AT Part Numbers
-96 38031-22Z70
96- 38031-22Z78
hmmm, the old diff on the car was the original M/95 S14 and the Viscous coupling was from Phatty's S reg (I think) S14a
I went and had a look myself and they are definitely incompatible. The shafts are the right lengths, but it seems the splined section has a lot thinner diameter. There's enough difference in the size for the S14 shafts to spin inside the S14a viscous coupling, you can hear the splines skipping.
I'm sure there's only 1 size of S14(a) shafts too. I'm truly baffled
I should be able to get the shafts back that went with Phatty's viscous coupling but it's a load of hassle and in the meantime my car is blocking their ramps and I wouldn't be surprised if they charge me extra for it ...... gahhhhhh
Just had another look and it also list 2 numbers for the diff end of the shafts
38220-4P010 for up to 96
38220-92L10 for 96on
ahhhh, that'd be it then. Thanks Mark
ahh well, you live and learn (even if it is really geeky stuff like this
At least I now know there are only 2 types it can be so if one doesn't fit it has to be the other one.
The only thing that would really shaft me is if the later type of shafts are a thicker diameter all the way along and not just the splined section and therefore use a different size of oil seal where they come out of the casing...... then they'd really need some
well I've learnt something new today aswell
do the oil seals for pre and post 96 have different part numbers?
I hope not.........
cant check until i get home
ok, I went and got the shafts that match the viscous unit and yes, the oil seal bits are the same diameter, which is good....
but it turns out there are other parts of the diff internals that also have different spline diameters
Luckily I have the rest of the internals of Phatty's diff in the car so the guys are going to swap bits over until they get it sorted.....
why is nothing ever simple???
I wonder why Nissan changed in the spec of these parts, would the later design be regarded as an improvement perhaps? ie. stronger?
also, would this difference be likely to alter the gearing ratios between the pre and post 96 S14s?
Its all very odd isn't it, i would have assumed they were the same on both. Just out of interest is this for your uprated experimetnal diff? If so when will you be testing it out?
it does seem very strange to me that they'd change something like this mid run and I can't think of any good reasons why they would. Although the old shafts are slightly thinner at the splined section, they're still a massive great lump of metal and I can't imagine strength being an issue or we would know about it with people here running big power through them.
Yes, this work is all to get my uprated viscous unit fitted and as long as they can now fit it ok, I'll be testing it as soon as the snow buggers off and I can find a decent sized bit of tarmac
When we do produce these, noone will encounter these problems as long as we can make sure they get the same viscous unit back. Although it's a pain at the moment, I'm very glad we've spotted this issue now and not when 10 people have their cars in pieces.....
thanks all for your help
Any idea of pricing on these yet Newclear?
nothing's cast in stone at the moment and I need to work out how it would work out with the exchange (especially as it's now crucial which type people have) but I think we're looking at £400 and I'm not doing this to make money, just covering costs.
Need to see if it's any good first though
Also need to see if it's a job people could do themselves, from what I can tell, getting the diff off and back on again is half the battle and the rest can be done yourself providing you're handy with a set of spanners and have a decent fitting instructions. Failing that, a decent gearbox place should charge under £200 all in to do the swap
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