The Triumph Dolomite Club - Discussion Forum

I've got a spare overdrive gearbox for the sprint. It looks okay in the pics, but is an otherwise unknown quantity, i.e., it's an unknown quantity. The one that's in is still okay, but having a good spare can only make it last longer - like taking a brolly stops it raining while you're out. So there should be time to have a look at it and see what it needs.

I've been reading the manual as research, but with no experience, I'm wondering what indications should I look for to check if it's likely still sweet or not, and what you guys think is likely worth doing to it as an overhaul? That is, without taking out another mortgage.

Also, how far do the springs in the overdrive fly when you take that apart? Special tools?

Graham

I'd strip it and check everything then replace whatever's worn out (helpful, I know).

So layshaft, layshaft bearings, thrust washers, input-mainshaft bearing + anything that looks worn + seals and gaskets + circlips + anything someone sensible who's done it before recommends later in the thread. I'm not sure whether the main bearings need to be replaced while you're there or if they're an "is it worn out?" item, baulk rings I'd inspect and probably reuse unless they're pretty bad. Then check the float on everything and put the appropriate washer in to get it where it should be.

For the overdrive I'd clean the filters and otherwise leave it alone. You need special tools to take it apart and when I had mine apart the price of spares vs the cost of getting someone who knows what they're doing to rebuild it meant I just boxed it up and sent it away. The springs will not fly at all iirc, there's not that much preload on them and plenty of thread on the studs they're on.
You will need a tool to take the plug out the bottom to get to the pressure filter but you can make that easily enough.

http://www.buckeyetriumphs.org/technica ... rhaul1.htm is worth a read.

I agree with everything that zombeh say's. I tackled my 1300fwd gearbox a short time ago and enjoyed the experience. I was very nervous about the complex manufacture of the assembly, but if you take things logically and keep things in order and clean then all should be well. It is quite clever how it all works!
Take your time and enjoy!

So far I've thrown them in and never had a problem. Internally they rarely go wrong.

With regard to the O/D, I have taken a few of these apart. By the time the nuts holding the springs have reached the end of the thread the spring tension has all but gone.



The main part that would need replacing is the cone clutch NKC0040 if the O/D is slipping. Readily available in the UK for £67 exchange.

Mad Mart wrote:The main part that would need replacing is the cone clutch NKC0040 if the O/D is slipping. Readily available in the UK for £67 exchange.

I take it that it's slipping or not is best found out in a car, and fixed after. Or is there an easy bench check?

Graham

What Dan said.

Only redo a Sprint box it its known to be noisy. If you think it is noisy check the diff and propshaft bearings first...

Rebuilding one if you havent done one before will be a serious exercise in needless frustration.

If you must have a rebuilt one try Mike Papworth or twist my arm....

Not for 6 months...and I cant normally get more than 50p an hour on my rebuild labour costs before you ask.

Jonners

Thanks for the advice. I'm still waiting to get hands on it, and I'll come back if there's more when it does.

Graham.