Pete Lewis Posted February 16, 2018 Report Share Posted February 16, 2018 Just stripped a local vitesse diff that ran overheated No obvious leaks of any consequence Out with the short shafts and youre welcomed by the obnoxious pong of cooked ep90 Splitting the carrier showed only about two egg cups of stinking oil it holds a pint.!!! The baked deposits on the bevel set and carrier are ...wonderful Suprising the pinion thrust race is just badley burnt the overun which seriously relies on splash was intact but the pre load shims were all screwed up All bearing taper rollers are a nasty orange colour , nothing has seized, as for the crown wheel and pinion tooth the finish is very black And the CW backlash was with a Dti around 0.018" well above spec , , The result of over economic service shedule to check oil levels has cost the diff its life The suns out , easy to check the diff , get the N/s wheel off and reach over the chassis.and check your diff levels and dont forget the gearbox This one is not for a rebuild Dont skimp on gettong oily Pete Link to comment Share on other sites More sharing options...
JohnD Posted February 16, 2018 Report Share Posted February 16, 2018 Could this be the reuslt of a blocked air vent, Pete? 'No obvious leaks', but heating could and does drive the oil out. John Link to comment Share on other sites More sharing options...
Clive Posted February 16, 2018 Report Share Posted February 16, 2018 I can't remember who it is, but there is an owner who reckons the only reason his diff has lasted at all is because it gets regular oil changes. Whoever really thinks diff oil in an old car (especially the old GL4 oil we are sort of stuck with) will last forever is deluded. Not only does it need regular checking (even if annual) it really is worthwhile draining and refilling every 10K miles or so. Especially if the driver has a heavy right foot! Actually makes me think there may be some superior alternative to the std GL4 oils. After all, we are talking 50+ years of oil development since that recommendation was made. Just think what oils were like 50 years prior to our cars being around, would you want to use that?? Link to comment Share on other sites More sharing options...
Pete Lewis Posted February 16, 2018 Author Report Share Posted February 16, 2018 John, didnt check the vent will have a gander in the am. The thing is completely crusted in 50 yrs of road crap I declined to clean it , it was caked and the vent is likley very blocked Oil in a diff should last long periods as there is no 'contamination' like you get from engines one reason theres no drain plugs ...mind you as clive says after 50 yrs whats it like !!!!! Well outside the designed criteria. Glad its not mine I would hazard the excess backlash is due to tooth wear Pete Link to comment Share on other sites More sharing options...
JohnD Posted February 16, 2018 Report Share Posted February 16, 2018 Easy to add a drain plug while you have the rear cassing off - there's even a flat surface underneath clearly deisgned for one! Mean old Sir John Black must have vetoed it. Straight hole and thread, with a conical sump plug, and it's done. John 1 Link to comment Share on other sites More sharing options...
Clive Posted February 17, 2018 Report Share Posted February 17, 2018 I think the very earliest diffs did have sump plugs, but deleted (cost saving no doubt, especially if the oil was considered for life) Link to comment Share on other sites More sharing options...
Pete Lewis Posted February 17, 2018 Author Report Share Posted February 17, 2018 my early parts list for Vit 1600 shows a std drain plug 114774 fro the diff there no upto or from noted Pete Link to comment Share on other sites More sharing options...
Colin Lindsay Posted February 17, 2018 Report Share Posted February 17, 2018 4 hours ago, clive said: I think the very earliest diffs did have sump plugs, but deleted (cost saving no doubt, especially if the oil was considered for life) Yes but whose life? I always wonder about that phrase. Car, driver or the oil itself? Any time I top mine up, which is usually annually if I have a car with an MOT, I siphon as much old oil out as will work before refilling. With the cost of repair or replacement units it's worth an extra few pennies of oil. 1 Link to comment Share on other sites More sharing options...
Paul H Posted February 17, 2018 Report Share Posted February 17, 2018 Check out the pic and see what happens when you run a diff with no oil . When I purchased my Vitesse Mk 2 in Feb 2016 it was an mot failure - headlights & brakes were the issue . I was told the gearbox needed to be replaced due to layshaft issues but no mention that they had forgotten to add oil to the diff. I trailered the Vitesse home and went for a test drive and only got 300 yrds when there was a bang and the diff disintegrated . I didnt have enough experience / confidence to tackle the job myself so Manvers Triumph ( no longer in business ) carried out building a new diff . They said they found engine blue suggesting the diff had been rebuilt and that the remains of the crown wheel & pinion were razor sharp . With the experience picked up over the last 2 years from this invaluable forum I would have had a go at tackling the job myself The seller had used the Vitesse in this condition for about 50 miles Mots etc and on handover said the car was making unusual noises and he thought it was the gearbox on its last legs. A bit of a baptism of fire and I wondered if I had purchased a money pit . 2 years on a lot of the mechanics have been changed though I still smile when I see her in the garage Paul Link to comment Share on other sites More sharing options...
scooter Posted May 16, 2018 Report Share Posted May 16, 2018 GL4 oils? Use a modern synthetic, light years better. Link to comment Share on other sites More sharing options...
Nick Jones Posted May 16, 2018 Report Share Posted May 16, 2018 On 16/02/2018 at 7:14 PM, clive said: I can't remember who it is, but there is an owner who reckons the only reason his diff has lasted at all is because it gets regular oil changes. Whoever really thinks diff oil in an old car (especially the old GL4 oil we are sort of stuck with) will last forever is deluded. Not only does it need regular checking (even if annual) it really is worthwhile draining and refilling every 10K miles or so. Especially if the driver has a heavy right foot! Actually makes me think there may be some superior alternative to the std GL4 oils. After all, we are talking 50+ years of oil development since that recommendation was made. Just think what oils were like 50 years prior to our cars being around, would you want to use that?? Could be me...... I change my diff oil before every 10CR (bi-annually or 8 - 10k) and use Redline shockproof HD 140. It's done maybe 50k and is now whining quite alot on load. Can hear it with the hood down 40 - 65 mph. It has had a thrashing. I reckon what really kills them is long periods at high speed (length of Germany on autobahns at 80+) purely because even when up to the mark, the oil volume is too small and they cook. I've seen a couple run low on oil and a couple of big saloon ones. Basically, if you tip one up and get a cup or so (or less) of black stinking gunge out, there's no point in even taking it apart unless you need the rear casing for the next one! Potential issue with GL5 (though I suspect not a real one these days) is it eating the yellow metal planet thrust washers. Nick Link to comment Share on other sites More sharing options...
scooter Posted May 16, 2018 Report Share Posted May 16, 2018 50k is better than they lasted from new! Link to comment Share on other sites More sharing options...
Clive Posted May 17, 2018 Report Share Posted May 17, 2018 7 hours ago, scooter said: GL4 oils? Use a modern synthetic, light years better. Any suggestions for a yellow metal safe synthetic? I use Comma sx 75/90 semi-synthetic in my gearbox, but that is GL4 spec. Link to comment Share on other sites More sharing options...
Pete Lewis Posted May 17, 2018 Author Report Share Posted May 17, 2018 Ive said before we had a a load failures suddenly on 8ton diffs due to the latest name over the door changed fron GL4 to Gl GL5 We had minced thrust washers in droves Use whats specified is for good reasons, but chance a supposed upgrade with no idea of the design requirement criteria Its your decision and await a failure Pete Link to comment Share on other sites More sharing options...
rlubikey Posted May 17, 2018 Report Share Posted May 17, 2018 Clive, I've just bought Motul Gear 300 75W-90 which is 100% synthetic GL5 because it specifically says it's yellow metal safe in the data sheet. I've no idea if it's any good or not; I'll tell you in 50,000 miles. No connection with Motul, etc. Cheers, Richard Link to comment Share on other sites More sharing options...
Anglefire Posted May 17, 2018 Report Share Posted May 17, 2018 On that link is actually says :API GL-4/GL-5 Link to comment Share on other sites More sharing options...
Pete Lewis Posted May 17, 2018 Author Report Share Posted May 17, 2018 If the spec covers the 4 and 5 then with a 4 in the plot its fine Pete Link to comment Share on other sites More sharing options...
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