Diff Problems
Author
Discussion

rhyspw

Original Poster:

312 posts

214 months

Tuesday 6th November 2012
quotequote all
Just removed the diff (3.46) from my Sag to find that the new diff I have bought (3.73) doesn’t fit! The flange to mount the front of the diff is a four hole arrangement whereas the diff from my car is a 3 hole, therefore the front brackets don’t fit. You can see in the below with the diff I took out of the sag on the left:



I assume that I must have been sent a diff out of a Tuscan? Can somebody shed some light on differences between the Tuscan, T350, Tamora & Sag? I thought they were all the same. However I see two options:

1) Send the diff back and get another 3.73 diff sent out -> Pain in the arse
2) Strip & fully rebuild/refurbish the diff - transferring the guts of the 3.73 into the casing of the 3.46

I was planning on stripping the new diff anyway to get the casing (very rusty) powder coated so I am assuming that the internals are compatible? It seems logical that they would be the same but would like some reassurance before I start down that road.

I am planning on getting some of the parts powder coated whilst they are off, does anybody know what the paint code is for the chassis so I can get them in the same colour?

Also got so Edward Quick de-cats to put on when the car goes back together smile

SSPPGG

2,120 posts

224 months

Tuesday 6th November 2012
quotequote all
ask john reid, grantura engineering

07799117211

he has lots of knowledge on the tvr diffs, and rebuilds them. he has done some btw diffs for me in the past

Brummmie

5,284 posts

243 months

Tuesday 6th November 2012
quotequote all
The black diff on the right looks like a Cerbera diff, i should know i have had mine out enough!
There are fewer holes in the nose of the other diff.
Craig at Dyno Torque has a diff out of Craig Winstanleys (or did have) with a proper locker diff in it, that would be the smart move if it is still available.
John at Grantura is a good guy, i had him uprate my internals if you want to go that route.

ETA the Cerbera diff if its a 4.2 is a cone type locker if its a 4.5 its a hydratrack, original one you have is Hydratrack, the C/W and pinion on the cone type might be interchangable, but the guts i dont think will..

Edited by Brummmie on Tuesday 6th November 19:56


Edited by Brummmie on Tuesday 6th November 19:57

jrb43

890 posts

277 months

Tuesday 6th November 2012
quotequote all
I had the same problem - I don't know if the 3 or 4 bolt pattern is actually specific to which T car you have or varied over the production cycle. I BELIEVE they're the same in all other respects but ask someone who knows better than me. I handed the whole job over to Warren at Topcats.

Mickywoosh

50 posts

177 months

Wednesday 7th November 2012
quotequote all
A slightly daft question but how do you know what diff ratio your car is without taking it off - are there any markings on the housing?

K4TRV

1,819 posts

274 months

Wednesday 7th November 2012
quotequote all
There's never a daft question on Pistonheads....................How's about you wind the prop flange 10/50/100 turns (depends on how accurate want t be) and count the drive shaft revolutions??

Otherwise get thy spanners out and start counting Crown wheel teeth and pinion teeth?

Guess which is easier.................8-))

rhyspw

Original Poster:

312 posts

214 months

Wednesday 7th November 2012
quotequote all
Or read the tag on the diff wink

Anyway it's all sorted. I could simply swop the brackets for four bolt ones. It seems to depend on what brackets was fitted at Tvr.

I have bought another "better" diff so I now have a 3.73 diff and a 3.46 diff for sale if anyone is interested......

EvoOlli

621 posts

185 months

Wednesday 7th November 2012
quotequote all
Hello Rhys,

what about the different flange for the prop shaft ? Could you transfer something from the original one to the 'new' one ?

rhyspw

Original Poster:

312 posts

214 months

Wednesday 7th November 2012
quotequote all
EvoOlli said:
Hello Rhys,

what about the different flange for the prop shaft ? Could you transfer something from the original one to the 'new' one ?
yep dont see why not

rhyspw

Original Poster:

312 posts

214 months

Wednesday 7th November 2012
quotequote all
Another question, does anybody know if there has ever been a BOM created for all of the bolts on a Sag/T350? I want to replace a load with new whilst I have everything apart.

EvoOlli

621 posts

185 months

Thursday 8th November 2012
quotequote all
rhyspw said:
yep dont see why not
I ask because on your photo it looks like the old diff has a 6 hole flange, which is very thick, against a 4 hole flange on the exchange unit.


rhyspw

Original Poster:

312 posts

214 months

Friday 9th November 2012
quotequote all
New diff....


rhyspw

Original Poster:

312 posts

214 months

Monday 12th November 2012
quotequote all
Productive saturday, new diff didn't have a fill plug so made one with a built in viton o ring:



Whilst I was at it I made new washers to hold the rear diffuser on as the others were rusty - needs polishing.



Also made new bonnet pins from SS as mine were looking worse for wear :

Allen key:



Flat head:



Not sure which I will use yet....

rhyspw

Original Poster:

312 posts

214 months

Monday 3rd December 2012
quotequote all
Finally got my bits back from the coaters. Everything can now go back together this week....


rhyspw

Original Poster:

312 posts

214 months

Monday 3rd December 2012
quotequote all
Also going to give these a try, hopefully will stop the rubber perishing on the exhaust mounts. Tufnol sleeves on stainless...



Legacywr

14,378 posts

210 months

Monday 3rd December 2012
quotequote all
Are you in engineering too Rhys?

glow worm

6,907 posts

249 months

Monday 3rd December 2012
quotequote all
Nice job.

TVR had two mounting plates for 3 and 4 bolt flange mounting. My factory supplied 4 flange diff was changed to 3 flange , simple matter of changing the plate. The plunge of the prop shaft changed and all my diff shunt problems went away smile .

rhyspw

Original Poster:

312 posts

214 months

Tuesday 4th December 2012
quotequote all
Legacywr said:
Are you in engineering too Rhys?
I'm afraid so.....

Legacywr

14,378 posts

210 months

Tuesday 4th December 2012
quotequote all
rhyspw said:
Legacywr said:
Are you in engineering too Rhys?
I'm afraid so.....
Me too...

http://benhammanufacturing.com/

rhyspw

Original Poster:

312 posts

214 months

Tuesday 4th December 2012
quotequote all
Legacywr said:
Well in future ill design it in 3d and send the models to you for manufacture wink