Diff Failure With Pics!

[Jon_Bmw 13]

The following pictures are what happens if you successfully keep up with a Caterham with a vastly greater power to weight ratio and you are in something french

 

The symptoms: Gearbox seemed to be getting more rattly as the track day progressed, one would think its just a french car throwing its toys out of the pram, right? It comes to 4.30 and I desperatly hang onto a pokey Caterham, then let it cool for one slow lap. Turn 180 degrees in the 'pit area' really slowly at about 15mph. It then crunches and sounds an awful lot like a driveshaft has popped out. Stop engine, get out look underneath to see Gearbox oil pouring out onto the tarmac. Get back in car and push it onto the grass to drain.

 

Nothing like being environmentally friendly huh? :eek: I'd rather ruin grass than nice tarmac any day. I'm no gearbox expert, but I knew it shouldn't be leaking gearbox oil from where it was. It was coming out near the flywheel plate 8O

 

Whipped the gearbox off last night to find unsuprisingly this:

 

 

 

Within the bellhousing there was the shards of the cracked casing AND... this:

 

 

 

:eek:

 

Oooops.

 

Where the bellhousing has been punctured is exactly where the Diff housing is on a FWD 205 box.

 

 

The diff in Situe still in the gearbox:

 

 

Yes there is the other part of the missing cog, still turning as per normal as it is slightly bigger than 50% of the total cog meaning it will still stay in place.

 

 

Partially dis-assembled Diff:

 

 

You can also notice the plastic splinned cog is also sheared.

 

 

The failure item closer up:

 

 

 

Looking above you can see that it has failed down the middle of a tooth as that part is MIA.

 

Damage to the diff casing:

 

 

Looking in the main diff housing:

 

 

 

So who says you need a torque monster to kill a diff, as far as I see you just need something French and a weapon behind the wheel 8)

 

The best bit, it drove home 65 miles on the a34/a303 with a no gearbox oil :cool:

 

 

Copyed off a BMW forum I use, I have to be slightly negative towards 205's otherwise they all get jealous of a £1000 car whopping theirs!

[Miles 331 1 Cars]

Very common even on std 1.6's and TD's, I had this happen on one of my first GTi's which was just over a year old many moons ago,

[wardy18 33 1 Cars]

Funny i changed a box last week which had done exactly the same thing, funny i did notice his right foot did look rather heavy, he span the inside wheel while goin round a corner then slammed it in the next gear only to break the 2 small cogs in the diff like you have and sent them throu the bell housing to then sheer off some clutch bolts as he carried on driving an then disappear throu another self made whole in the bell housing, muppet, i cant say much thou i did this in my first 1.6 gti years ago, both cars completely standard!

[skeggyrik 3]

Nice work! I always like seeing pics like this, makes me think twice about how much grief I give my own car!

Good post.

 

Good excuse to fit an LSD?

Edited September 29, 2008 by skeggyrik

[Jon_Bmw 13]

The poor car had been getting a beasting most of the day. 3 drivers at a track day means the car gets some abuse. Combined with an mi16, slicks and a few weapons(bad drivers ) behind the wheel, it was inevitable I guess.

 

It had a 1.9 box on it, which is really the worst one to go for in terms of ratios, so its now a good time to swap it for an mi16 box which arguabley has the best 2nd and 3rd ratios of all standard boxes for track use. Forth is nigh on identicle in the 1.6 box and the better 1st in the 1.6 box isn't used on track. I don't think I can be bothered buying 2 Box's and opening them up and swapping things

 

Miles, is there a cure or uprated 'small' cogs for this as it could be quite an annoying occurance.

 

On the LSD front, it would be nice, but the rest of the car doesn't really justify that expense Very tempting though...

[Super Josh 4]

As Miles' says, they all do this eventually. Only real cure is to fit an LSD, I'm afraid You say that your car doesn't warrant the expense, but you can keep swapping the diff to any new 205 you buy

 

 

 

 

Josh

[welshpug 1,666]

even a boggo 1.6 git will benefit massively from a slippy diff

[Cameron 16]

Phwoar, nice work!

[Jon_Bmw 13]

Hopefully I have an mi16 box sorted now from a mate.

 

Are the diffs the same on the 1.6/1.9/mi16 boxes or did they make them stronger on the more powerful engine boxes? I presume they are identicle

[SPGTi 2]

Did the same to my 1.9 box a few years ago. A lot of the cogs exited the case though and I had no drive at all.

 

 

 

Steve

[jonnie205 1]

fit the xsara vts box, bigger diff in them or go for a slipper

[philfingers 5]

yes diffs are the same AFAIK.

You say the spec doesn't justify it but a 4.4 Mi16 CWP with std 1900 gears and an LSD is the way to go.

By the sounds of it the spec with mi16 and slicks justifies it!

[Jon_Bmw 13]

I think I have an mi16 box sorted now with the right reverse and clutch mech. Is it a nasty job to change the gears over to the mi16 box as my 1.9 8v box is a goner. I've just has a look at the 1.9 ratios, they are the same in first and second, but better suited in third and forth(shorter). Phil you have me thinking now! Damn you!

 

I understand what you are saying, but the car doesn't owe me much over £1200 suprisingly, so half the price of the car on a LSD seems slight overkill. The other way I look at it is that I could hopefully get it to around 180-200bhp for the same cost. Controlling inside wheel spin can be done with ones right foot when using slicks, i'm sure not to the same degree as a LSD, but the difference IMO is not £700's worth!

[philfingers 5]

i picked my TranX up brand new for £410 a few years ago, they are around for that kind of cash. Send me a PM with your email address and I'll send you a excel spreadsheet gearing caculator thing

Phil

[Jon_Bmw 13]

Phil thanks for the offer, I actually already have it, but hadn't initially cottoned onto the fact that the reason the 1.9 box is so 'poor' is because of the final drive! Poor, for what I want anyway.

[Simsy 0]

What actually causes the failure, massive abuse?

 

Can you simply bang a Xsara VTS box on and use the same shafts and speedo drive from the 205 then. In which case a 306 XSi/S16 box would also fit?

[Miles 331 1 Cars]

Just the quality of the gear's, I had one of these go with a car that was only 14 months old which I had from new, It never got loads of abuse.

The Diff's are not really the weak point, More of the Sun and Planet gears + The Diff pin which causes the problems which never got changed

[Jon_Bmw 13]

I've gone with the easy option in the short run, replaced it with a 1.6 box. My mi16 has just got a load more fun as well! Its crazy now, change from 2nd to third at full revs, or thereabouts, and its doing 5500rpm in third. This is how this car always should have been. You are right in the power band from 40mph upwards.

 

Cheers for the box Westy!

[Simsy 0]

Just the quality of the gear's, I had one of these go with a car that was only 14 months old which I had from new, It never got loads of abuse.

The Diff's are not really the weak point, More of the Sun and Planet gears + The Diff pin which causes the problems which never got changed

 

Oh right, so i assume they changed the design of the Xsara and 306 box later then? I guess the ratios of a 306 XSi 8v would be the best match to a 1.9?

 

Do you do gearbox rebuilds with different parts to avoid this issue Miles?