Transmission noise and speedo wonky

[Tom]

I recently noticed some transmission whine which seems to have got louder over the last few days - it's hard to tell really, perhaps I was turning the stereo up to compensate or maybe its an old noise that's got louder . Whatever, it is now at the "this sounds like it might get expensive" level and the speedo has also gone mad, which doesn't seem to be a coincidence as you will see below. Do the following symptoms ring a bell with anyone?

• Whine similar to an old fashioned gearbox - think Inspector Morse Jaguar S-type
• Pitch depends on road speed, not engine speed
• Noise only heard when engine is pulling (reduces if not accelerating, stops if decelerating or clutch disengaged).
• When changing gear, the noise is heard briefly as you pass through the gate.
• Here's the strange bit, which may indicate the something to someone: The speedo misbehaves in sympathy with noise - drops to zero if throttle closed, wiggles madly when engine the noise is heard (under the conditions previously described)
• No sign of any leaks etc.
• Gearchange and clutch feel completely normal.

A mechanic friend is going to have a look for me tonight but if anyone recognises these symptoms or has advice of what to look for, it would be much appreciated.
I've owned the car for 8 years of daily use and it has covered about 101k to date, so I'm sure this noise isn't "normal".

 

[Guest]

I've only had my 2.5 lux for a month but have noticed similer things. I hear a whine from the gearbox but I've been told this is the norm for a car with the gearbox in the back and with it being a 21 year old car, I've not noticed whether it tallys with the clutch in or out.

Every so often my speedo either stops working, has a slight delay before it springs into to action from a stand still, or just suddenly jumps up to max speed and down again whilst cruising at a steady speed. I'm not sure if my '86 944 has a cable drive or a sensor for the speedo but either way it may need some attention, cleaning it up or summat like that.

 

[peanut]

Hi Tom very good discription by the way.

If the noise is not with the engine speed then obviously you can rule out the engine which is good news.

The noise being worse when accelerating suggests to me like one of the CV's or maybe the diff but possibly a rear wheel bearing ( think that just about covers everything at the rear of the car lol

It would be interesting to let the car coast with the engine off somewhere where it is safe to do so and see what you hear. I usually find a long garden wall and coast along it at about 15-20mph so the noise is reflected back to me. I usually do this with the car door open and hanging out the car with my head under the cill which is probably a little alarming for anyone coming the other way lol.

I think the fact that the noise reducing when the clutch is depressed is very significant and probably diagnostic but I cannot for the life of me think what it is indicative of at the moment.


I need a sugar fix

 

[Tom]

Having taken my mechanic friend for a drive and talked to a few friends too, the verdict is that it's probably the diff bearings. This would explain the effect on the speedo, since the speedo sensor takes its signal from the diff - perhaps the bearing has failed and there's enough movement to stop the sender from detecting the rotation? It's booked in for further investigation next Thursday. Apparently it's often best just to get a replacement box - Anyone know of a good source (Herts/Essex)?
I'll post details of the garage's findings and solution, in case it is useful to anyone with similar symptoms.

 

[zcacogp]

ORIGINAL: peanut
I need a sugar fix

Peanut,

You may need a sugar fix, but this site is about cars and Tom's car needs a gearbox fix.

So take such comments elsewhere. www.nicecupofteaandasitdown.co.uk is a good one.

(And on a serious note .. Tom, if the speedo pickup is electronic, and the diff bearings are very worn, it is not beyond the realms of possibility that the sensor is not at a constant enough distance from the pick-up to read a regular signal, hence the erraticness of the reading. Hope you get it fixed soon.)


Oli.

 

[Tom]

Hi Oli,

On a very serious note: It is the diff bearings and it's going to be very expensive unless I can get hold of a good second hand box. Dooh!

Tom

 

[zcacogp]

Really expensive? Last time I had a gearbox rebuilt (by Nichol Transmissions in Kidderminster, but lots of places will do it), it was about £450. I did have to remove the gearbox from the car and take it to them, but that wasn't too difficult.

That was for a Mk1 Golf GTi gearbox, and therefore would be quite comparable with a 944 box.


Oli.

 

[Tom]

Figures I've had so far have been:
- Gearbox rebuild: "a couple of grand"
- Recon gearbox £1800
- Bearing replacement "from" £650
- Pinion bearing replacement £800
- Crown wheel bearings - probably cheaper to get another box.

Perhaps Golf boxes are much cheaper to repair - I had a Golf GTi (Mk2) gearbox rebuilt in Longbridge for about £500 - mind you that was about 15 years ago!

 

[rcsalmons]

I have a gearbox which is in the process of being rebuilt (and has been for some time). Its from a 82k mile car and has no gear wear and is having all bearings replaced.

Its a long story but I no longer have the car and the gearbox is surplus to my requirements.

Let me know if you are interested.

Rich

 

[rcsalmons]

Another point, if you have your gearbox rebuilt be careful where you take it. The 944 box needs to be shimmed when being rebuilt. Most general gearbox places will just throw new bearings, syncros in it etc.

I talked it through with a number of people and by far the most knowledgeable was Jon Mitchel by a long way.

Give him a call and discuss the noise.

All the best

Rich

 

[Diver944]

ORIGINAL: Tom

Perhaps Golf boxes are much cheaper to repair - I had a Golf GTi (Mk2) gearbox rebuilt in Longbridge for about £500

They are also far, far, far, far, far more plentiful and therefore due to economies of scale all the parts will be much cheaper.

Closest figures I can find on Google are over 21 million Golfs made up to 2002. There were just over 154,000 944s made ever

 

[Tom]

Hi Rich,

I'm certainly interested in your surplus gearbox - I've emailed you for some further details.

Cheers

 

[Tom]

After more than 3 months, I'm finally back on the road (it's a long story). For the record, I eventually decided on having the 'box rebuilt with a full warranty. I've got a selection of the most worn parts and the main wear was on the diff bearings, which were worn right through the hardening into the soft stuff. The speedo problem was not fixed by the rebuild however - I had to replace the sender.

I now have a new problem which will hopefully be fixed under warrenty - very occasionally the box is jumping out of 3rd gear. It has done this 4 times now in about 500 miles of use on mixed roads. This has only happened at low speed with low torque. Any ideas what might be going on?

 

[Tom]

The "jumping out of 3rd" issue has now been fixed by adjusting the gear linkage - it hasn't recurred since being adjusted in October.

 

[Wigeon Incognito]

Do you mind saying how much your gearbox rebuild was and where it was done?

Reading this thread has got me a little worried as mine has something of a whine.

 

[Wigeon Incognito]

A bit of searching has answered the above.

I'm still a bit concerned though! Maybe I can use the old 'turn the volume on the stereo up' trick for a little while before I tackle this one.

 

[Tom]

I'm pretty sure the whine had been there in the background for a while but then suddenly got much louder - it was more of a "I hope I'm going to get home tonight" kind of noise than a "is that a slight whine from the back somewhere?". I hope yours is more like the latter...

 

[Wigeon Incognito]

ORIGINAL: Tom

I'm pretty sure the whine had been there in the background for a while but then suddenly got much louder - it was more of a "I hope I'm going to get home tonight" kind of noise than a "is that a slight whine from the back somewhere?". I hope yours is more like the latter...

Yep, more like the latter. It's noticeable if the radio is off but it doesn't sound out of place.

Maybe I should start putting some cash aside for a possible gearbox rebuild in the future but not worry about it right now.

 

[edh]

Widgeon

They can go on for ever with noisy geaboxes - there's a common problem - not diff bearings though (pinion bearing? - I don't pretend to know anything about gearboxes [])

They are most noisy in 4th & 5th IIRC (mine's nice & quiet, but my 924S's were both a bit noisy)