17 replies to this topic

[Lukie-J]

Ok, so I made it to Crystal Palace Parade, agonisingly close to the park for L2B this weekend just gone.

Slowly driving through traffic at roughly 10mph in second gear and the thing completely locks, no warning, no noises just like it's been slammed into reverse!

Clutch in stopped the engine cutting out and it started driving again, maybe 20 yards and it happened again.

5 hour recovery home to Somerset and I'm left with a 1275 engine and a knackered (I assume) gearbox/diff.

On inspection, with car jacked up and wheels spun back and forth I can notice the passenger driveshaft pot joint drifting in and out about 5mm with the spline moving with it so some play in the diff somewhere?

So...

Is replacing a gearbox a do-at-home job? (I've replaced engines on minis countless times and just about everything else on mine)

If I can't find a 1275 gearbox, will a 998cc gearbox fit? (assuming it's A+ as well).

I know there are some parts that are better off kept from the 1275 gearbox, but could they be the components causing the locking up?

Thanks

Edited by Lukie-J, 23 May 2016 - 08:07 PM.

[Mini 360]

Cant speak for the fault but Im running a 998 box on a 1275 with no issues.  Both A+.  Gearbox is easily a do at home job if you have a hoist or a few mates to fit the car over the front subframe/engine combo.

[Lukie-J]

What's the gearing like? Ok on the motorway etc?
I'll give the Haynes manual a thumb-through and see. Getting the engine out isn't a problem, it's that actual gearbox transfer that I haven't done before.

Cheers.

[Dusky]

5 mm of inwards play? Id say your diff is busted.

[mini13]

yep sounds like the dif is about to exit through the casing to me,

 

engine out, diff off and asses the damage. asuming its just the diff easiest/best thing is to transfer your crown wheel to a 4 pin diff and refit

[Lukie-J]

Will start to dismantle it at the weekend and see what's what. I'm happy giving it a go but not sure about the inner workings of the gearbox/diff, specifically what can be transferred and what needs to be machine to fit.

[Lukie-J]

yep sounds like the dif is about to exit through the casing to me,
 
engine out, diff off and asses the damage. asuming its just the diff easiest/best thing is to transfer your crown wheel to a 4 pin diff and refit

Yeah, I think I was lucky it was a low speed in traffic, not on the motorway!

[Dusky]

A 4 pin diff really is not needed tho. Miglia's (used) to run the minispares reinforced pin with bushed gears. Quality of the oil, way of driving,.. Are way more important imho.

[Lukie-J]

I've done a bit of research, looks like it's a normal A-series engine (teardrop-shaped timing chain cover, dipstick tube, no visible webbing on the back).

Don't have an engine number on it so can't tell apart from visible differences!

 

Would a metro 1275 gearbox fit onto it as I've been offered a good one. I assume it would be A+ so unsure.

Thanks for all the responses so far. The diff has a lot of 'backlash' so want a complete replacement including gearbox really just to keep it simple.

 

EDIT: I've also been offered a 998 a-series gearbox. I don't understand much about ratios so what difference would the final drive make to the actual driving experience? (eg higher revs at the top end, slower acceleration).

Edited by Lukie-J, 24 May 2016 - 07:28 PM.

[adam_93rio]

From your dis riptide id say you would just need a new diff. Mine went the exact same but I was going a bit quicker and it burst its way through the casing.
I'd pull the diff housing off (can be done in situ but easier to pull the engine out if you have the means), and inspect the diff. Then replace as needed.
There shouldn't be any need to change the entir box if it's just the differential gone

[MRA]

A 4 pin diff really is not needed tho. Miglia's (used) to run the minispares reinforced pin with bushed gears. Quality of the oil, way of driving,.. Are way more important imho.

 

Sorry Dusty, but will have to disagree on this one mate, the factors are stacked against a conventional pin or even the very best of the best pins available, the best available lasts me 3 days in my 1380 turbo, however the safety factors alone means fitting a 4 pin is the best way to go.

 

The reasons diff pins fail, high torque, high gearing and high traction, 2 out of 3 of which a miglia doesn't posses.

[adam_93rio]

I've found the picture of what happened when mine went, so thought I'd share

[mini13]

with the diff its a cost vs effort thing.... if you spend the 163 quid on the x pin diff, you'll never have to worry about it ever again, or you could stick a std on in there and and it'll be fine forever too... or wreck the box in 6 months time, very  much depends on driving style.

 

the main thing Ive seen kill diffs is wheel spins, basically with eonough power going through the diff to spin a wheel will wear the diff pin pretty quick, till it makes a bid for freedom,

 

Personnaly I'ts somthing I would always do on a non standard engine, or if the engine/ box was out.

[Dusky]

A 4 pin diff really is not needed tho. Miglia's (used) to run the minispares reinforced pin with bushed gears. Quality of the oil, way of driving,.. Are way more important imho.

 
Sorry Dusty, but will have to disagree on this one mate, the factors are stacked against a conventional pin or even the very best of the best pins available, the best available lasts me 3 days in my 1380 turbo, however the safety factors alone means fitting a 4 pin is the best way to go.
 
The reasons diff pins fail, high torque, high gearing and high traction, 2 out of 3 of which a miglia doesn't posses.

Ill rephrase it: you probably dont need it
Its very good to fit an xpin, but i see a lot of.owners making the expense when they only run 40 bhp :/ You run a monster ;)( take me for a drive one Day?)

[MRA]

 

 

A 4 pin diff really is not needed tho. Miglia's (used) to run the minispares reinforced pin with bushed gears. Quality of the oil, way of driving,.. Are way more important imho.

 
Sorry Dusty, but will have to disagree on this one mate, the factors are stacked against a conventional pin or even the very best of the best pins available, the best available lasts me 3 days in my 1380 turbo, however the safety factors alone means fitting a 4 pin is the best way to go.
 
The reasons diff pins fail, high torque, high gearing and high traction, 2 out of 3 of which a miglia doesn't posses.

Ill rephrase it: you probably dont need it
Its very good to fit an xpin, but i see a lot of.owners making the expense when they only run 40 bhp :/ You run a monster ;)( take me for a drive one Day? )

 

Yes, but ask anyone who builds gearboxes for a living and the one thing that shines brightly is the amount of MPi's with broken diffs, these don't do much wheel spin, they do have high FD ratio and sticky tyres with normal 1275 torque values, I would simply fit a cross pin to be safe.  plus how much is a new case nowadays ?

 

There are faster out there Dusty

Edited by MRA, 24 May 2016 - 10:59 PM.