Gearbox noise Spit 1500

[Dannyb]

For years now I have had an annoying rattle from the gearbox with O/D. I also have a spare gearbox which did the same when fitted a few years ago. It sounds like a pinking sound or load rattle and only happens when the car it cruising or deceleration above 2500 revs. It's OK under load. 

I've run the car in gear up on axle stands and is OK. 

All gears seem to do this. The gearbox shifts OK and o/d works fine. 

Anyone else had this or think they know what it is. 

Danny

[Clive]

possibly layshaft/gear chatter? Did your box haxe the little springs at the front behind teh bellhousing? Some boxes didn't have them from the factory, the ones that did often lose them at gearbox change time.

 

[Dannyb]

23 minutes ago, Clive said:

possibly layshaft/gear chatter? Did your box haxe the little springs at the front behind teh bellhousing? Some boxes didn't have them from the factory, the ones that did often lose them at gearbox change time.

 

Yeah definitely had them. I remember fitting them. Could it be they are worn as they were the original springs since the car was made. 

Danny

[Clive]

6 minutes ago, Dannyb said:

Yeah definitely had them. I remember fitting them. Could it be they are worn as they were the original springs since the car was made. 

Danny

No idea! They are there to keep it all under a tiny amount on tension, not much so I doubt they will wear enough.

But I am no expert. I have lost many of those springs though.

Plan B. Use some 85/140 gear oil. That often settles stuff down.

[Dannyb]

Thanks Clive. I'll try some 85/140 oil and see how that goes. What about sawdust 🤔. 

Danny

[Clive]

55 minutes ago, Dannyb said:

Thanks Clive. I'll try some 85/140 oil and see how that goes. What about sawdust 🤔. 

Danny

I have bought some redline "shockproof heavy" oil, but it won't be suitable for your gearbox. But plenty suitable choices, just no GL5 (too slippery for synchros and probably the overdrive)

[Dave Clasper]

On 27/02/2022 at 16:29, Clive said:

Did your box haxe the little springs at the front behind teh bellhousing?

Mike Papworth advised to only refit (any) one of these three, as causes undue wear on a component (can't remember which one).

It seemed a bit odd, though I took his advice, as He does appear to know his stuff

[Dannyb]

11 hours ago, Dave Clasper said:

Mike Papworth advised to only refit (any) one of these three, as causes undue wear on a component (can't remember which one).

It seemed a bit odd, though I took his advice, as He does appear to know his stuff

That will be interesting to find out which one to keep. At the moment I have drained the oil and replacing it with 84/140 GL4. I'll see how that goes. Just waiting for another ltr to arrive as I forgot it takes just over a litre with the o/d. 

I still have a spare box with o/d and Bell housing sitting on the shelf which is in good condition but made the same noise when fitted a few years ago. Not sure if that's got any springs fitted as I never had the bell housing off since I've had it. 

Might one day have it checked over and refit but I don't feel my back is up to it at the moment. See how this one gets on with the thicker oil. Maybe a job for next winter. 

Danny

[Dannyb]

I've added the thicker oil and took it for a run today. Noise still there but not as load. 

I also emailed Mike Papworth. He said could be end float on lay gear or maybe tooth broken off 1st motion shaft. Which is common on the single rail box with the bellhousing oil seal. 

Because the spare box has the same noise I may fix that and swap it out. Meanwhile keep driving. 

Danny