A bit of a leak

[nightSpirit]

After a glorious drive this evening, I noticed a small pool of fluid on the rear diffuser underneath the diff (where the diff bolts through the chassis. Smell was of transmission fluid. Couldn't see anything suspect though...

Any thoughts? and what trans fluid is needed and how much (and how do you swap it)?

[Coldaswell]

Hi. Had this on mine. They all seep a bit it appears. It may be fine and just a weepy seal or a bit of normal seepage as the whole thing is clamped to the frame which I presume flexes a little.

Mine, on the other hand, had a cracked gear drive case when I bought it. The upper rear mount is machined in such a way as produce a weak corner next to the mount. Some fracture here and it's very hard to tell if that is what has happened as even Radical didn't spot it the first time. The fluid runs around the case along the seal line and drips from the underside making it quite hard to trace, and only tends to leak when being driven.

In the end getting it rebuilt was a good thing as the gears inside mine were pretty knackered anyway. Now it's all fine and even a bit quieter!

[nightSpirit]

Thanks. I'll check it out more when I get time. It wasn't a pool of fluid but it was certainly more than seepage.

[Sigmamark7]

As I have just discovered to my enormous cost, too little oil in the transmission can have a major impact on your pocket. Check it or get it checked out sooner rather than later, because £4k against £4 for some oil and a gasket is a bitter pill to swallow!!

[nightSpirit]

Very true...can you tell me which oil is needed and how easy it is to do?

[nightSpirit]

Sigmamark7 said:

As I have just discovered to my enormous cost, too little oil in the transmission can have a major impact on your pocket. Check it or get it checked out sooner rather than later, because £4k against £4 for some oil and a gasket is a bitter pill to swallow!!

It looks like (from a few threads here and there) the diff usually leaks and it generally leaks or leaks a lot...does this sound right?

Can you tell me Sigmamark7 what oil and gasket you refer to? Do you mean the complete diff gasket for £14 odd from big R? Also what brand of oil do I use (75W 90?) and is it easy to swap?

Any advice guys, appreciated. I'll be calling big R next week anyway but wanted to look into beforehand.

[Sigmamark7]

Hi - apologies for not replying earlier, but sadly I can't help with info on the oil. I bought my lightly used car a few months ago and ran it for the first time at Bedford last month. It needed an oil and filter change and I was also running out of revs on the straight at Bedford, so I took it to Corinium Motorsport to get the engine oil changed and a taller ratio put in. When the Diff Gear Drive Unit was dismantled, they found that the end of a shaft had failed and complete with the Gear Ratio Sprocket Nut was lying at the bottom of the housing. To cut a long and painfully expensive story short, the swarf generated by the failure had pretty much destroyed all the contents of the unit, necessitating a full rebuild. It is hard to judge why the shaft failed and it could be poor quality, poor machining, over tightening of the nut (although it had never been apart before), or just one of those inexplicable failures, but it was suggested that the drive unit could have been short of oil.
One thing is certain, I will be making damned sure that it is never short of oil again and is stripped and checked regularly going forward, because the total bill has spoiled my prospects of actually racing the car this year.

[nightSpirit]

Sigmamark7 said:

Hi - apologies for not replying earlier, but sadly I can't help with info on the oil. I bought my lightly used car a few months ago and ran it for the first time at Bedford last month. It needed an oil and filter change and I was also running out of revs on the straight at Bedford, so I took it to Corinium Motorsport to get the engine oil changed and a taller ratio put in. When the Diff Gear Drive Unit was dismantled, they found that the end of a shaft had failed and complete with the Gear Ratio Sprocket Nut was lying at the bottom of the housing. To cut a long and painfully expensive story short, the swarf generated by the failure had pretty much destroyed all the contents of the unit, necessitating a full rebuild. It is hard to judge why the shaft failed and it could be poor quality, poor machining, over tightening of the nut (although it had never been apart before), or just one of those inexplicable failures, but it was suggested that the drive unit could have been short of oil.
One thing is certain, I will be making damned sure that it is never short of oil again and is stripped and checked regularly going forward, because the total bill has spoiled my prospects of actually racing the car this year.

st that sounds like not much fun! I'll call rad on Tuesday and order oil and see what they have to say. All I can do for now is check that all appears tight.

[nightSpirit]

The plot thickens...I've been under the car the past few days and replaced/tightened the various 14mm etc bolt/nut/spacer combos that hold the diff to the chassis. I noticed tonight that the rear lower point had some pitting and hair line cracks (nothing too bad but still enough to cause a leak) on the casing side. I've put a ring of silicone sealant on the washer and re-tightened it so 'hopefully' it'll do the trick.

Ended up having to refill the diff (1ltr of oil) from the level plug hole.

[Richard7K]

To fix up the slightly leaky trans in my car, I have to keep a close eye on the bolts on the side of the case (it's often the top one just towards the rear of the car and lockwire has sorted it) and a replacement O ring did wonders for keeping the oil inside. I am running Titan Supergear 75w 90 in my car.

And thanks for getting those parts away NightSpirit. They'll be here in NZ in a day or so.

Rich

[nightSpirit]

No problem at all.

I'll keep an eye on the bolts/nuts (assume you mean the allen head ones?). I'm actually thinking about selling up though as it dawned on me the other day that the chances of me using this car as it should be used are going to be a lot less than I thought.