TR6 Diff

Author
Discussion

Mr Tiger

Original Poster:

406 posts

135 months

Wednesday 26th April 2017
quotequote all
Hi,

Does anyone know if the diff from a 2500 saloon is the same as a TR6 except for the back plate? Are they interchangable if the back plate is swapped ?

Thanks,

Chris

Yertis

18,655 posts

273 months

Sunday 30th April 2017
quotequote all
A bit late but I'm fairly sure the front casing is different – I think I tried this in about 1988.

RCK974X

2,521 posts

156 months

Wednesday 7th June 2017
quotequote all
As far as I know..... (my disclaimer !!)

the *main* diff case and innards are the same, but the rear casting is different (as said).

On the saloons, there is a bolt on nose extension which is not fitted to TR range.

The saloon diff has a spline type 'drive' cog in the nose, which connects with the extension drive piece, which supports the trailing arms.

--BUT--

I understand you CAN actually change all the bits over, and fit the TR type 4 bolt flange and its seal, but you have to undo the
main nut (which crushes collapsible spacer for endfloat....), so you have to be very careful about retightening it afterwards.

But it is possible......

2500 saloons had a 3.45, 2000 was a 4.11, and some 2000 autos got a 3.7.

TR5 and 6 PI had a 3.45, but US ones (carb) were 3.7

also I believe the Dolly Sprint had a 3.45 with same innards but fitted in a solid axle....


Edited by RCK974X on Wednesday 7th June 07:22

Mr Tiger

Original Poster:

406 posts

135 months

Thursday 8th June 2017
quotequote all
Thanks for the replies both.

I took the plunge and bought a 2500 saloon diff off eBay a couple of days ago. It should arrive today or tomorrow.

The seller seems to be very knowledgeable and stated that they are interchangeable. I think he mentioned something about a solid spacer allowing the front plate to be changed without altering end float. I don't understand this though and have a big learning curve ahead!

I won't be starting work on this for a couple of months but when I do, the first challenge will be getting the existing diff out. Easier said than done on a TVR as chassis tubes more or less surround the diff. It could be fun and games...gulp.

Cheers,

Chris

RCK974X

2,521 posts

156 months

Thursday 8th June 2017
quotequote all
Info.....

The front flange (or drive cog in saloon) is held on with a large nut, and this nut ALSO controls the pinion endfloat, which is set very precisely
to ensure quiet running (by making sure the gears mesh just right). They typically have a spacer between two 'cone' type bearings.

(have a look at some diagrams - they are all pretty much the same design...)

Diffs can have either a collapsible spacer (which is not supposed to be reused if you take it apart) or a solid spacer with shims. this then controls how much float/space is between the bearings....

Can't remember what Triumph diffs got which !!

If it has a solid spacer, should be easier, as it's just a dismantle, swop, and reassemble. If it's collapsible, then you have to tighten very carefully
so you can feel where nut hits the spacer....and stop there....

(Note, I've never done this... so it's just what I read....but sharing it in case it helps. I HAVE seen both saloon and TR6 diffs close up though).

Hope this helps....

Mr Tiger

Original Poster:

406 posts

135 months

Friday 9th June 2017
quotequote all
RCK974X said:
Info.....

The front flange (or drive cog in saloon) is held on with a large nut, and this nut ALSO controls the pinion endfloat, which is set very precisely
to ensure quiet running (by making sure the gears mesh just right). They typically have a spacer between two 'cone' type bearings.

(have a look at some diagrams - they are all pretty much the same design...)

Diffs can have either a collapsible spacer (which is not supposed to be reused if you take it apart) or a solid spacer with shims. this then controls how much float/space is between the bearings....

Can't remember what Triumph diffs got which !!

If it has a solid spacer, should be easier, as it's just a dismantle, swop, and reassemble. If it's collapsible, then you have to tighten very carefully
so you can feel where nut hits the spacer....and stop there....

(Note, I've never done this... so it's just what I read....but sharing it in case it helps. I HAVE seen both saloon and TR6 diffs close up though).

Hope this helps....
Thanks for the info. It makes a bit more sense now.

Chris

Yertis

18,655 posts

273 months

Friday 9th June 2017
quotequote all
Mr Tiger said:
Thanks for the info. It makes a bit more sense now.

Chris
My father rebuilt my diff – we was highly skilled engineer and the end result was superb (once we'd reset preload torque using inch/pounds rather than foot/pounds). Reason I'm telling you this is that if you decide to remove the crownwheel/cage etc from the main casing you'll need a special tool which 'spreads' the case just enough to get the crown wheel out – you won't do it otherwise. We had to make this tool.

Mr Tiger

Original Poster:

406 posts

135 months

Monday 19th June 2017
quotequote all
Yertis said:
My father rebuilt my diff – we was highly skilled engineer and the end result was superb (once we'd reset preload torque using inch/pounds rather than foot/pounds). Reason I'm telling you this is that if you decide to remove the crownwheel/cage etc from the main casing you'll need a special tool which 'spreads' the case just enough to get the crown wheel out – you won't do it otherwise. We had to make this tool.
Sorry for the late reply. Thanks for the further details, all useful info.

Chris

GT6M

21 posts

89 months

Sunday 25th June 2017
quotequote all
Some info for ye, the diff dont need a spreader,
use 2 pry bars, or bigg screwdrivers , and place ont crown wheel bolts,one either side, an prise it oot, dont come on first go, then turn to a new bolt, and lever agen,
it,ll come oot easy this way. ..Got to use the bolt heads, and diff case.

it should be a nice tight fit whenst pulling oot.
if it comes oot freely, then it needs moer shims
put,n it back in, tap the bearing races wid a copper or hide hammer, till its down.

re front/rear bits, basicly the same, { Stag, diff rear case, and diff size pin bearing }
to get a saloon diff onto a TR, then ye need the TR cross mounting bit
and the TR drive flange
put a new oil seal in whilst its oot

front nut, IF its a NYLOK, then its a crush spacer, be care full
if its a castle nut, wid split pin, its a solid spacer.

If ye aint got a tool t,hold the spline sleeve, then use a Windy gun
or clamp spline bit wid some bigg water pump type pliers, and try windy gun
Can lock the CW and the output shafts too, this works.
it,ll all become clear whenst ye look at it,!!!

Underneath either nut, is a v tight fitting spline carrier,
this needs t,come off, so too does the v v tight fitting spacer under it
only realistic way t,get thee,s off / oot, is to tap the pinnion oot into diff case
After the CW is oot the way.

Ye will be advised to tek the carrier wid the CW out, and replace the cup thrusts
they will be well worn, one always wears moer than the other, { round a bouts }
cant say what size, butt, it,ll need at least 40thou moer than whats in now!!

IF its got fibre washers in there, then there a good chance that 1, maybe both are missing, generally just one, as one goes, it frees pre load, and saves the other
DO not get re-placement fibre washers, get the PB type
mod them with a few wee indents on each side for oil retention, same too for the wee cups on side gears

if ye dont check it over, it could be noisey on over run, clonking, due to play in gears int diff planets
mek them as tight as poss, a wee tap into place
as in 100 miles or so, they be bed in, and just right.
mek em slack, easy fit in, they will be too slack in 100 miles
Note, tight is so the outputs cant be turned by hand, but can turn with a bigg barr

long reply, but its a biggish job fitting a diff,
so best sort it befoer its in car

AND, befoer tek,n t,bits, check the tooth contact pattern
with the CW under load, wak a chisel between CW and diff case
then turn input shaft over a few times
its got tobe checked under load, as there a bigg diff between load ,an no load

any questions, just ask, ill help ye re doo it,

M

Mr Tiger

Original Poster:

406 posts

135 months

Monday 26th June 2017
quotequote all
Thanks GT6M for the extra details.

It'll be a couple of months before I'll be able to make an attempt at this job. Although I must admit, it's looking increasingly daunting...

Chris

Yertis

18,655 posts

273 months

Tuesday 27th June 2017
quotequote all
GT6M said:
Some info for ye, the diff dont need a spreader,
use 2 pry bars, or bigg screwdrivers , and place ont crown wheel bolts,one either side, an prise it oot, dont come on first go, then turn to a new bolt, and lever agen,
it,ll come oot easy this way. ..Got to use the bolt heads, and diff case.

it should be a nice tight fit whenst pulling oot.
if it comes oot freely, then it needs moer shims
put,n it back in, tap the bearing races wid a copper or hide hammer, till its down.

re front/rear bits, basicly the same, { Stag, diff rear case, and diff size pin bearing }
to get a saloon diff onto a TR, then ye need the TR cross mounting bit
and the TR drive flange
put a new oil seal in whilst its oot

front nut, IF its a NYLOK, then its a crush spacer, be care full
if its a castle nut, wid split pin, its a solid spacer.

If ye aint got a tool t,hold the spline sleeve, then use a Windy gun
or clamp spline bit wid some bigg water pump type pliers, and try windy gun
Can lock the CW and the output shafts too, this works.
it,ll all become clear whenst ye look at it,!!!

Underneath either nut, is a v tight fitting spline carrier,
this needs t,come off, so too does the v v tight fitting spacer under it
only realistic way t,get thee,s off / oot, is to tap the pinnion oot into diff case
After the CW is oot the way.

Ye will be advised to tek the carrier wid the CW out, and replace the cup thrusts
they will be well worn, one always wears moer than the other, { round a bouts }
cant say what size, butt, it,ll need at least 40thou moer than whats in now!!

IF its got fibre washers in there, then there a good chance that 1, maybe both are missing, generally just one, as one goes, it frees pre load, and saves the other
DO not get re-placement fibre washers, get the PB type
mod them with a few wee indents on each side for oil retention, same too for the wee cups on side gears

if ye dont check it over, it could be noisey on over run, clonking, due to play in gears int diff planets
mek them as tight as poss, a wee tap into place
as in 100 miles or so, they be bed in, and just right.
mek em slack, easy fit in, they will be too slack in 100 miles
Note, tight is so the outputs cant be turned by hand, but can turn with a bigg barr

long reply, but its a biggish job fitting a diff,
so best sort it befoer its in car

AND, befoer tek,n t,bits, check the tooth contact pattern
with the CW under load, wak a chisel between CW and diff case
then turn input shaft over a few times
its got tobe checked under load, as there a bigg diff between load ,an no load

any questions, just ask, ill help ye re doo it,

M
You should write for Haynes. thumbup

garagewidow

1,502 posts

177 months

Tuesday 27th June 2017
quotequote all
GT6M said:
Some info for ye, the diff dont need a spreader,
use 2 pry bars, or bigg screwdrivers , and place ont crown wheel bolts,one either side, an prise it oot, dont come on first go, then turn to a new bolt, and lever agen,
it,ll come oot easy this way. ..Got to use the bolt heads, and diff case.

it should be a nice tight fit whenst pulling oot.
if it comes oot freely, then it needs moer shims
put,n it back in, tap the bearing races wid a copper or hide hammer, till its down.

re front/rear bits, basicly the same, { Stag, diff rear case, and diff size pin bearing }
to get a saloon diff onto a TR, then ye need the TR cross mounting bit
and the TR drive flange
put a new oil seal in whilst its oot

front nut, IF its a NYLOK, then its a crush spacer, be care full
if its a castle nut, wid split pin, its a solid spacer.

If ye aint got a tool t,hold the spline sleeve, then use a Windy gun
or clamp spline bit wid some bigg water pump type pliers, and try windy gun
Can lock the CW and the output shafts too, this works.
it,ll all become clear whenst ye look at it,!!!

Underneath either nut, is a v tight fitting spline carrier,
this needs t,come off, so too does the v v tight fitting spacer under it
only realistic way t,get thee,s off / oot, is to tap the pinnion oot into diff case
After the CW is oot the way.

Ye will be advised to tek the carrier wid the CW out, and replace the cup thrusts
they will be well worn, one always wears moer than the other, { round a bouts }
cant say what size, butt, it,ll need at least 40thou moer than whats in now!!

IF its got fibre washers in there, then there a good chance that 1, maybe both are missing, generally just one, as one goes, it frees pre load, and saves the other
DO not get re-placement fibre washers, get the PB type
mod them with a few wee indents on each side for oil retention, same too for the wee cups on side gears

if ye dont check it over, it could be noisey on over run, clonking, due to play in gears int diff planets
mek them as tight as poss, a wee tap into place
as in 100 miles or so, they be bed in, and just right.
mek em slack, easy fit in, they will be too slack in 100 miles
Note, tight is so the outputs cant be turned by hand, but can turn with a bigg barr

long reply, but its a biggish job fitting a diff,
so best sort it befoer its in car

AND, befoer tek,n t,bits, check the tooth contact pattern
with the CW under load, wak a chisel between CW and diff case
then turn input shaft over a few times
its got tobe checked under load, as there a bigg diff between load ,an no load

any questions, just ask, ill help ye re doo it,

M
hiya Marcus wavey