172/182 Gearbox Weakness

[MarkM]

I have just been reading the media thread about the turbo'd 172 and the owners gearbox worrys.

What is the realistic torque limit of the box (used as a daily driver)?

On a big power car what component fails in the box and does it suddenly fail or is it more of a wear issue?

Can the components of the gearbox be upgraded or is the strength of the box dictated by the overall design?

I have also heard that the box cant cope with a plate type lsd. Is this gearbox poor in design or just at its upper limits coping with the standard engine.

Obviously how you treat the box is a big factor but it is a performance car so occasional hard use should be covered.

 

[Lagerlout]

As far as I'm concerned the JC5 gearbox is bearly capable of dealing with the torque from a standard F4R'd Clio. Mines started to get loose after just 24,000 miles. I have a feeling that some of the internals may be made from cast dairy milk.

 

[haitch]

great conversion but whats the point of having all that power (172 turbo) if you fear the box.

 

[edde]

The gearbox is just a variation of the 1.8 16V box ok some bita re better but its nothing amazing.
Hence why Renault have gone and made there new 6 speed box with Nissan called the J series.
It not bad but abuse kills them. Renault boxes have never liked being rushed.
Its the selector and syncros which are week you can get better ones but the prices is silly.
LSD can be done its no problem.
However LSD usually means you'll hammer i so it will die but no quicker than an none LSD one.

 

[Fred@BTM]

megane RS on left, clio cup on right

you can see why i've gone for the megane rs box!!

 

[edde]

you can see why i've gone for the megane rs box!![/IMG]

Because the JC5 won't fit that engine?

 

[Fred@BTM]

yeah and its made from butter

 

[Guy]

you can see why i've gone for the megane rs box!!

because its cleaner??

or is it heavier thus lowering the car more?

 

[Fred@BTM]

49kg = Meggy RS
35kg = 172 cup

 

[BenR]

tbh mark, the box stands up to abuse quite well, its not the peice of cheese many flame it to be.

Granted it doesnt like large torque spikes, but what gearbox does?

Drag racing, clutch dumping and river dancing on the pedals is what kills things.

The syncros dont like being rushed, but they wont break the box. On older type box's which use a circlip to retain the diff, they had a real problems with 'popping'. This does not mean the box is weak at all, it simple means there is a weak point in it, that stupid circlip. All gears in all box's are ALWAYS trying to un-mesh themselves, engaged gears are always pushing against eachother and the shafts can flex under high loads or damage their bearings. And if a gear strips its because the shaft flex's and cog mesh allows it to spin, and it only needs one miss.....but i've not seen this happen on any clio, they just pop diffs non stop.

Newer 182's seem to have a bolt in crown wheel instead of the circlip and i've not seem this fail. The circlips fail, and once they pop they just cant stop as a chamfer is put on the circlip retention groove.

From what i've seen, the box's are not weak but they just dont stand the type of driving that they are subjected to. I've never broken one in any manner, and i wouldnt call myself an easy driver. But rushing shifts, especially with a quickshift, doesnt help, torque spikes from dumping clutches etc damages things.......but that does on any gearbox, evo's and subaru's destroy box's.

Turbo 172's, you'd need it to come on song pretty strong for the torque spike to be of such a high ratio gain to blow it, nitrous maybe. But i've not seen a super high torque turbo yet.

I'm not a gearbox man at all, i hardly look at them, but i've never had a problem and neither do those who drive well.

 

[Fred@BTM]

LOL at riverdance!!!

 

[greer182]

how much is a new 182 gearbox.

mines done 24k and has gone really loose, plus its clunking from 2nd to 3rd, was going to change the oil and see if this made a difference.

does'nt feel the strongest piece of kit. but dont know.

whats the best course of action do you think.

i do give it some stick, but not abuse, plus what where these cars made for. if i wanted to drive like a sunday driver i would have bought a 1.6 focus or something etc....

no dis respect to 1.6 focus;s. lol

 

[16v_jon]

second and third syncro's wear first as they are the most used gears for most people.
there are loads of weak points in the jc5 box , the 129 version 172 and cup seems to be the most problematic due to the stick most people give them and the circlip holding the diff in.
im on my 3rd box in 16k miles all are not new BTW the first one the 5th gear broke and the second box the planetary gears broke and came through the casing!
the 3rd one i sent to a specialist box builders they fitted uprated syncros and quaife cut gears , and replaced the circlip to the device fitted to the 182 (130) box now much better and after 12k miles still smooth as butter and only cost £540+vat

 

[rmccardal]

Is your surname Flatley ?

im on my 3rd box in 16k miles all are not new BTW the first one the 5th gear broke and the second box the planetary gears broke and came through the casing!

 

[MarkM]

the 3rd one i sent to a specialist box builders they fitted uprated syncros and quaife cut gears , and replaced the circlip to the device fitted to the 182 (130) box now much better and after 12k miles still smooth as butter and only cost £540+vat

what was the company called?

 

[GordonD]

I hear the Mk3 Cup cars have a sequential shift box with steering wheel paddles for shifting. Paddles would solve the problem that the current sequential box needs major surgery to fit the gear change linkage through the firewall. But is the new box really new, and maybe won't fit earlier Clios with their narrower engine compartment, or is it just the previous sequential box with a different gear shift?

 

[edde]

I hear the Mk3 Cup cars have a sequential shift box with steering wheel paddles for shifting. Paddles would solve the problem that the current sequential box needs major surgery to fit the gear change linkage through the firewall. But is the new box really new, and maybe won't fit earlier Clios with their narrower engine compartment, or is it just the previous sequential box with a different gear shift?

The Mk2 and the Mk3 (most probaly spec isn't out yet)) race cars have sequchial Sadev 6 speed boxes with LSD but there not the road cars.

The road cars with have the new J series 6 speed gearbox cobuilt by Nissan and Renault. rive the new DCI 105 Clio as thats got the same gearbox (different ratios the dci has though).

You can get a sequenchial box fitted into a road going Mk2 it would be a pain £6k fitted you need a few bits new driveshafts for starters and they boxes arn't that usable all the time as they designed to work on full throttle upshifts for races. The Euro cup racers have a better sequenchail box but the problems using one means noone would bother.

 

[MarkM]

edde - what do you reckon to 16v jon 's gearbox mod with the quaife gears (some shorter ratios would probably be a good idea?) and uprated syncros.

What would be an approx cost for fitting be aswell.

630 (gears and syncros) + 800 (lsd) + 500? (fitting) = call it 2k.

A bit pricey but would be a nice mod.

 

[16v_jon]

what was the company called?

geartorque in westhoughton , bolton

 

[edde]

edde - what do you reckon to 16v jon 's gearbox mod with the quaife gears (some shorter ratios would probably be a good idea?) and uprated syncros.

What would be an approx cost for fitting be aswell.

630 (gears and syncros) + 800 (lsd) + 500? (fitting) = call it 2k.

A bit pricey but would be a nice mod.

Sounds like a good modification the 182 box has been made better by this extra bit.

I'd go for longer 5th maybe 4th as well personally. Maybe a longer first and second depends where you drive the car though and what you want.
Best get a second hand gearbox personally so you cna swop back at a later date also I'd be tempted to stick a LSD in there.
Might as well stick a new clutch in therw whilsts your at it so that another £200 or so.

 

[mr bognor]

My one went bang on my old Mk 1 172 and it was std