MX5 transmission noise?

[Paul V]

Just been looking a mates MX5, it has a really bad transmission noise, sort or whining rumbling noise, its either the diff or the gearbox, had it jacked up with the engine/gearbox running, gets much worse when you increase the speed, trouble is with it on axles stands its hard to tell which one is the problem. One the road it’s noisy under load and very bad when engine breaking, almost goes with the clutch out or in neutral.

[chimburt]

if it's come on over time ( getting louder ), and varies with road speed, independent of gear, i'd be inclined to think diff?
how old/miles?

just being nosey

[Paul V]

Mates not too sure but thinks it came on pretty quick, doesn’t make any difference what gear it in but is road speed dependant, I thought it either likely to be output shaft bearing in the box or the diff bearings, just hard to tell under the car as is very loud and the sound is travelling, could do with getting it on a proper ramp.

The cars an import and had the transmission oils changed within the last few years, the cars done 100k.

[cptsideways]

It'll be the inner gearstick gaitor, they break up & allow LOTS of transmission noise into the cabin. About £25 for a new one.

[Paul V]

No this is something broken, lots of mechanical noise from either the box or diff, definitely not just some normal noise getting in.

[benjc]

What year/model is it? It could be propshaft vibration, that tends to be lower down the rev range and displays itself under load.

[Paul V]

It’s a 1991 Eunos 1.6, think the noise is a bit too loud to be a propshaft, had a prop out of balance on an old Capri and you could feel it through the car, this you can’t feel, the car drives normally, gear change etc but making lots of noise, with the car jacked up it’s almost painful with the engine running and in gear, because it’s so loud it’s hard to tell which bit is making the noise, definitely related to wheel speed though.

[benjc]

Tough one to call over the net. Could be anything from a knackered VLSD (but you would get a lot of "clunking" with that) to a knackered clutch throwout bearing, to a wasted gearbox.

Time to take it to the nearest 5/roadster specialist I am afraid! On the plus side clutches are quite cheap, as are gearboxes (I just picked up a box for £200).

Good luck.

[Paul V]

Mates just rung the local specialist who said it sounds likely to be the diff, about £350 for the recon one doesn’t sound too steep.

[benjc]

try russ at www.everythingmx5.co.uk/.

Is that for an open diff, a VLSD or a Torsen? New or used?

[Paul V]

It’s a reconditioned unit, presume it’ll be an LSD like for like, I’ll ask my mate though.

That’s a nice MX5 you have in your profile, what sort of power do you get out of it?

To add, the quote was from everythingMX5 unless there is more than one MX5 specialist in Romford

>> Edited by Paul V on Tuesday 31st May 14:33

[benjc]

That sounds a bit steep to me, but I am a cheapskate. £350 should be able to score him a Torsen with half shafts and prop.

www.mx5roadsters.com/forums/showthread.php?t=2644

This sold for £250 I believe.

Mine was last dynoed at 235bhp/210ft/lbs, but it should be a bit more now

[Paul V]

Don’t think it's cheap but didn’t sound to bad for a recon, after seeing what it costs my TVR one would cost.

Yours must be rather good fun then.

[benjc]

I bet, I know of a secondhand VLSD that went for £50 the other day...it may be worth putting a "want" post on the mx5ocforum.co.uk or mx5roadsters.com as a lot of the tubby guys swap their VLSDs for Torsens.

"Lively" is one word I would use to describe my car.

[Paul V]

Mate is moving in 2 weeks so needs the car fixed ASAP, they are fitting it on Saturday, might not be the cheapest way but at least should be sorted for when he moves.

[Paul V]

Was the diff in the end, replacement went on at the weekend and all is well again, the gearbox is making a small amount of noise but not enough to worry about yet.

[skinny]

i have a similar noise - changed gearbox and diff oil, new clutch, it's still there. sounds like metal scraping on the floor when you decelerate. i'm suprised a new diff sorted the problem in your car tho given it goes away when you put the clutch down (same as in mine...)

[benjc]

If it is a Mk1 1.6 it is likely to be the propshaft vibrating. You will need to replace the propshaft, diff and halfshafts for a 1.8 unit as this had better damping.

>> Edited by benjc on Tuesday 7th June 19:57

[Paul V]

The diff was making noise under load, yes very much like metal scraping, either with power applied or engine braking, apparently the diff oil smelt burnt when it was drained. By the way it’s a mates car.

[Paul V]

No honest, it is

Do have an MR2 though