The Triumph Dolomite Club - Discussion Forum

They will probably accept your old 3.89 as a return too, they have done this for me on odd occaisions - mind you, I HAVE been dealing with them for over 25 years!

Steve

Carledo wrote:They will probably accept your old 3.89 as a return too, they have done this for me on odd occaisions - mind you, I HAVE been dealing with them for over 25 years!

Steve

I did ask that and they asked what condition it's in. I said its not noisey and works fine and they said they would take it. They said it's not as desirable as the 3.63 but as it's working they would have it.

I am told that the TR7 4 speed diff (which is also 3.63) has uprated bearings...

I have fitted 2 of these to my TR7 engined 1850 and they go in the existing case no worries. As to "uprated" they didnt seem any
better than the existing (already whining) doly 1850 diff that was in there originally and the TR7 engine soon finished off. The 4 speed TR7 diff is similar to Dolly/Marina ones but has longer half shafts and tubes and different back plates with bigger drums and better brakes which IIRC are double piston rather than single slider.

Later TR7's get the SD1 style diff, so form your own conclusion....I think the small diff is ok up to about 110/120 bhp but no more.

Your 3.89 diff is a desirable upgrade to any dolly 1300 owner.

My 2 cents...

Jonners

Managed to get through to Spitbitz today and decided they will be the best option. They were knowledgeable and helpful like fitchetts. Garenteed working diff for under £150 and I don't need to send mine to them so would be able to keep it as spare or pass it on.

This little package turned up today. 3.63 diff.

So the 3.63 diff is fitted and it's made such an improvement. Not changing gear as quick and the car cruises a lot better. Keeps up with traffic a lot better now and it's much quieter than the old diff and also tighter. The old diff had a bit to much back lash which you could feel when lifting off the throttle. The new diff is nice and smooth.

Steve