Discussion
If you remember some time ago I posted a question regarding running temperature and the smell of burning ( http://www.pistonheads.com/gassing/topic.asp?h=0&a... ), well today whilst under the car I noticed something a little odd at the rear around the diff area. The exhaust was covered in a light spraying of oil (diff oil I assume) as was the underside of the car, again only around the diff area. The drive shafts are dry it seems to be in and around the prop coupling.
Now I'm speculating here but this would appear to be that burning smell I've been getting every so often from the car. It's hard to say what's going on here but has anyone had experience with the diffs losing fluid like this? I don't think it's a lot as it's been happening over time and the coverage is light (sort of).
Now I'm speculating here but this would appear to be that burning smell I've been getting every so often from the car. It's hard to say what's going on here but has anyone had experience with the diffs losing fluid like this? I don't think it's a lot as it's been happening over time and the coverage is light (sort of).
Yes its common in older cars. The diff flange seal is leaking and/or leaking past the pinion shaft splines. You need to replace the seal and seal up the splines.
You will have to drop the propshaft, undo the pinion nut and take off the flange. Flip out the old seal and replace. After thoroughly cleaning the splines I'd put some silicone behind the flange nut and then nip that up to maintain the pinion pre-load.
You will have to drop the propshaft, undo the pinion nut and take off the flange. Flip out the old seal and replace. After thoroughly cleaning the splines I'd put some silicone behind the flange nut and then nip that up to maintain the pinion pre-load.
Looks like a slight leak along the splines, have you changed the oil in the diff? It's such a small amount of leakage I really wouldn't worry about it, it will not get any worse. A quick cheap fix is drop the prop, clean spline bolt area with an electrical contact spray and then paint around the coupling cup area and coupling bolt head with liquid metal, job done.
You probably think it's a lot of oil but it will be less than a tablespoon of oil and its probably took 10k miles to leak that amount.
You probably think it's a lot of oil but it will be less than a tablespoon of oil and its probably took 10k miles to leak that amount.
snowwolf said:
Looks like a slight leak along the splines, have you changed the oil in the diff? It's such a small amount of leakage I really wouldn't worry about it, it will not get any worse. A quick cheap fix is drop the prop, clean spline bolt area with an electrical contact spray and then paint around the coupling cup area and coupling bolt head with liquid metal, job done.
You probably think it's a lot of oil but it will be less than a tablespoon of oil and its probably took 10k miles to leak that amount.
Mick, I have to disagree. That is a leak and it needs fixing. I wouldn't want all the crap under the car even if the oil leak won't compromise the diff. He might as well do the seal as well. It's not an onerous job.You probably think it's a lot of oil but it will be less than a tablespoon of oil and its probably took 10k miles to leak that amount.
It normally only starts leaking when royal purple has been put in it or other synthetic oils, I personally think you can cause more problems in the diff by removing the coupling as it has been set up with the crush washer behind it, when the bolt and coupling has been removed and put back after re sealing, the bolt needs to be marked before removal so it can be tightened to that mark plus 8% I would guess most garages other than monkfish and a few others will know that and will just tighten it back up which will result in a toasted diff.
Some things I think are best dealt with by a simple fix and no more leakage and clearances stay good in the diff, I went through all this on my old monaro and it still draped along the splines, liquid metal cured it and only took an hour to do.
Some things I think are best dealt with by a simple fix and no more leakage and clearances stay good in the diff, I went through all this on my old monaro and it still draped along the splines, liquid metal cured it and only took an hour to do.
MyM8V8 said:
Mick, I have to disagree. That is a leak and it needs fixing. I wouldn't want all the crap under the car even if the oil leak won't compromise the diff. He might as well do the seal as well. It's not an onerous job.
snowwolf said:
There is quite a range in the pinion pre-load figure, so you'd have to be pretty daft to get it that wrong you toast the diff. I've noticed when I strip old diffs they loose tightness with lots of use anyway. Your figure of the mark plus 8% to maintain pre-load sounds OK. I build my diffs very tight, all figures to the max, that's because I built my first one to the lower figures and it was clunky.I do agree, it is always best to get problems sorted, but for £20 he can fix it himself, only 4 coupling bolts to undo, if he wants to do it himself he can save the £20 and will post you the gear to do it free of charge 
and it is the best on the market.
and it is the best on the market.MyM8V8 said:
There is quite a range in the pinion pre-load figure, so you'd have to be pretty daft to get it that wrong you toast the diff. I've noticed when I strip old diffs they loose tightness with lots of use anyway. Your figure of the mark plus 8% to maintain pre-load sounds OK. I build my diffs very tight, all figures to the max, that's because I built my first one to the lower figures and it was clunky.
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