Diff Question

[MarkDeTriomphe]

There have been a couple of incidents recently with people knocking holes in the rear casing of their small chassis Triumph diffs - so I wonder if the experts on here could cast an eye over the picture below and let me know if this is likely to be a problem (now or in the future).



The blemish at the back of the diff is a small pit / hole, about 7mm by 2 mm, although it  does not appear to go all the way through the casting.  

The diff itself feels OK - not notchy at all and very little play - but I have not driven it and don't really want to fit it if likely to explode within a few miles.

So the question is - could this just be a minor imperfection in the casting or is it a sign of imminent destruction?

Sorry about the picture quality - will try to take a clearer shot later.

Thanks, Mark

[MarkDeTriomphe]

Slightly clearer in this photo:

[GT6 M]

Mark, why dont you split the diff to fin oot.
very simples to doo, wont be upsetting any settings.
should only take 10 mins tops to split.

is this a 3.27 you worried aboot.
E Bay one!!!

M

[Deleted User]

796 wrote:

Mark, why dont you split the diff to fin oot.
very simples to doo, wont be upsetting any settings.
should only take 10 mins tops to split.

is this a 3.27 you worried aboot.
E Bay one!!!

M

Marcus How can you tell its a 3.27 I have seen a couple but the seller has no idea what ratio it is
Thanks :)

[GT6 M]

easy Ole Boy, turn the prop end around.
if it goes just past 3 turns, for one turn of the drive shafts, its a 3.27

over 3 1/2 then its a 3.63
nearly 4, its a 3.89

stopp faffing, tek it to bits for peace o mind. ;) ;)

M

[Deleted User]

796 wrote:

easy Ole Boy, turn the prop end around.
if it goes just past 3 turns, for one turn of the drive shafts, its a 3.27

over 3 1/2 then its a 3.63
nearly 4, its a 3.89

stopp faffing, tek it to bits for peace o mind. ;) ;)

M

Are Spitfire 1500 3.27 as standard though :)

[GT6 M]

;D ;D ;D, yes and no

Swiss Spittys had em as standard.
alot get put in cos they,or sellers no no any diffrence

you had a count up of turns yet,!!!
its easy. go doo it, thats an orderous request.
an let me no. :) :)

3.63 and 3.27 have tha same number of pinnion teeth.
in my findings, its always the pinnion that looses a tooth.
so 3.63 and 3.27 should be the same,

prob the 3.27 go,moer, cos they got more power to  as they more likely to be in a six pot.

M

[Deleted User]

796 wrote:

;D ;D ;D, yes and no

Swiss Spittys had em as standard.
alot get put in cos they,or sellers no no any diffrence

you had a count up of turns yet,!!!
its easy. go doo it, thats an orderous request.
an let me no. :) :)

3.63 and 3.27 have tha same number of pinnion teeth.
in my findings, its always the pinnion that looses a tooth.
so 3.63 and 3.27 should be the same,

prob the 3.27 go,moer, cos they got more power to  as they more likely to be in a six pot.

M

Okay I shall ask the seller to do the check you said
Thanks I am a bit new to this stuff so any help is welcomed :)

Oh diff part number is FR 28149 is that any help.

[GT6 M]

Ohhh, im no talking to you Mark with the last posts.
just clicked last posts, so did no see it wernt ye,

must look at the posters name. :B
M

[MarkDeTriomphe]

Marcus - thanks for the reply.

Diff in question is a 3.89, non ebay but unknown quantity nonetheless.

I'll have a peep inside, although as I said originally, the hole does not seem to have penetrated yet (testing with a pin) .

Do I assume that broken casings are only the result of something inside letting go first?

Cheers,
Mark

[shedmonkey]

I have a daft diff question again-and od  gearbox question

In prep for being allowed in the shed again next week and fitting me new second hand box /diff etc -which grade of diff/oil should I be using again?

Is it 80/90 GL4 ? that can be used in in box and Diff?

GT6M - will get me sel a big socket and knocking stick to take the clinky clonk diff apartr next week so we can see whats happened!

[Clive]

80/90 gl4 is ideal. Been using the comma version for 20 years in all my Triumphs.
Or any 80 or 90 gl4 stuff. Avoid GL5 and all will be well with the world.

[Richard B]

MarkDeTriomphe wrote:

Do I assume that broken casings are only the result of something inside letting go first?

It was in my case.


I think a tooth (or something else) broke and then jammed against the casing, BANG!

Ooops there's a hole in my diff and no drive.  :'(

[thescrapman]

You can tell the ratio by the colour paint daubed liberally on the input shaft nut.

Pink is 3.27 I think, white is 3.63.

Red is 3.89.

Please take all these with a pinch of salt, I am trying to remember off the top of my head.

But.... they used the same colour for different ratios in different cars I think.

So a white on a small saloon diff is probably different to white on a big saloon.

Cheers

Colin

[Deleted User]

thescrapman wrote:

You can tell the ratio by the colour paint daubed liberally on the input shaft nut.

Pink is 3.27 I think, white is 3.63.

Red is 3.89.

Please take all these with a pinch of salt, I am trying to remember off the top of my head.

But.... they used the same colour for different ratios in different cars I think.

So a white on a small saloon diff is probably different to white on a big saloon.

Cheers

Colin

Seller has put yellow on the input shaft :-/ but p/no is FR 28149 is that any info to someone :)

[Clive]

FR is 3.63 ratio. (Assuming nobody has swapped CWP after it left the factory)
3.89 are FH KD HC FD
3.27 KC

[Deleted User]

cliftyhanger wrote:

FR is 3.63 ratio. (Assuming nobody has swapped CWP after it left the factory)
3.89 are FH KD HC FD
3.27 KC

Thanks I thought it was a USA 3.27 spec. :)

[Nick Jones]

ajp wrote:

I have a daft diff question again-and od  gearbox question

In prep for being allowed in the shed again next week and fitting me new second hand box /diff etc -which grade of diff/oil should I be using again?

Is it 80/90 GL4 ? that can be used in in box and Diff?

GT6M - will get me sel a big socket and knocking stick to take the clinky clonk diff apartr next week so we can see whats happened!

GL4 and ideally it wants to say "hypoid" or "suitable for differentials" on it somewhere.

Nick

[shedmonkey]

cheers- my input shaft is green!....and so is the one on my diff