low mileage car problems

I just ordered a brand new differential for my 25 k miles (certified) GTB turbo. The gears and bearings there are inside the old one are totally destroyed and full of rust. Fortunately the rust did not affect the gearbox, that is still ok even if it had to be cleaned by the rust deposit.

The mechanic told me that's a problem that just very low mileage cars have, or cars that were sitting for long time, mine is one of those.

So sometimes better choose a car that did some miles.

The only good news is that i realized that i must have my 18 k miles 328 differential opened and cleaned as soon as possible, before it will be destroyed by rust too.

ciao
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Do you change gearbox oil every year?

Ciao

 

No car requires gearbox oil change every year. 3x8 has the big issue of no oil in the differential, that's the problem. You can change gearbox oil even every month, but if you do not drive the car the differential will have big problems.

Ciao

 

I purchased the car just two months ago. I just wrote what my mechanics told me. If the problem was the old oil, my gearbox would be destroyed but it's still Perfect: i think you do not focused what destroys diffenerential gears.

Ciao

 

No he did not. He did not realize yet that the oil Goes on the differential gears just if the gears rotates at high speed and the oil warm up a lot as it's not enough to change oil to have oil touch the differential gears, that are all above oil Level so they aren't touched by the new oil you put inside the gearbox. Hope i explained why it's much more important to drive the car than change the oil in the gearbox.

Please think about it

Ciao

 

The problems are the two satellites inside the differential: they are almost sealed in, there is just a small hole (1/2" inch more or less) through which the oil can reach the two satellites. The hole is at an higher level than the oil level so it has to be very hot and shaked very quickly to reach those two satellises. Change often gearbox oil can help a bit, but if you do not drive the car for a long time, it won't ever reach the two satellites. The mechanic says the differential works more with "oil vapours" than oil itself. Yes, if you have fresh oil in the gearbox is better, but not enough to avoid that problem, that is avoided (even with old oil) if you dirve often the car and not just for few miles.

I know Rifledriver has a lot of knowledge about those cars, but i think in this case he has to learn something more. My mechanic is not stupid, serviced hundreds 3X8 since 35 years, his shop is 20 yards from the factory and worldwide famous: if he told me that, means he saw many times that problem. He says if you open a 3X8the differential, you always will see some big play and the bigger play is on the low mileage cars.

Here a new differential costs 1800 euro + VAT

ciao

 

The gearbox has no sign of wear: it's perfect, you can see pictures, while the differential is destroyed and now has been thrown into the garbage. I already have the new one installed. My Lamborghini Countach had separated oil for differential and 4 liters (4+ quarts) of oil in it, so all cars are different from eachother with different problems. The 3X8 differential has the big problems that it does not touch the oil level ever while rotating so the draining process is by far faster with rust problems and wear problems.

And if you do not drive often the car for several miles, the oil will never reach high temperatures and will never make wet enough the differentials gears (the two satellites there are inside)

This is what i learned from the mechanic and after seeing the differential opened and out of the case. It was impressive to see how destroyed the satellites were while the gearbox gears were in perfect conditions despite being in the same case with the same oil.

ciao

 

no, there aren't, sorry

ciao

 

there isn't any spray nozzle nor oil passage from the oil pump to differential gears. The oil pump just serves the crankshaft. The gearbox has no oil pump. Differential has big oil problems, that's a factory fault that becomes bigger if you do not drive the car often and enough.
I saw another differential on the mechanic shop desk with a lot of play: he told me "that's very common in rarely driven cars". They say the only 3x8 cars that do not suffer of that problems are high mileage cars regulary driven. I have to say that mine had an enormous play and a lot of rust, that means the car sitted for a lot of time and probably when it was almost new so the rust started 20 years ago or something like that. Usually those cars start sitting when old, so rust starts when the car is just old and has not enough time to destroy gears like it did on my differential. My car did just 9 k miles in its first 15 years of life, then it started to move: many rust as it sitted when new and 15 k miles done with rusted gears from 2004 to today, so the differential gears broke off. Usually vintage cars do many miles when new and low when old, mine did the opposite so it destroyed the gears. That's my theory about what happened.

ciao

 

There isn't any oil passage from the gearbox oil pump to the differential gears: that's the reason why they fail.

But you are right : there is a gear pump in the gearbox, but not for the differential case zone, just for the gearbox shafts. I did a mistake, it's not easy this tech discussion in english.

I saw it with my eyes.

THERE IS NO OIL IN PRESSURE THAT GOES TO THE DIFFERENTIAL SATELLITES NOR THEY ARE TOUCHED DIRECTLY BY THE OIL IN THE GEARBOX SUMP.

Changing oil frequently helps, but it's not enough to solve the problem as you must have oil flying at high speed into the gearbox to give the possibility to some oil to reach the differential gears. Ok? that's not an opinion, it's a fact. An expensive fact...

ciao

 

There is not any possibility, but i think it's not necessary to inspect. The way to know if there is some problem inside the differential is this: drive the car at low speed and at low rpm in a turn, so the differential has to work. If you hear some soft "tock - tock" noise from the rear axle (like a supension bushing problem) just when the car turns, you have better to take out the differential, open and clean it from rust and register it to reduce play among gears before destroying it..
If you hear a more strong "tock-tock" noise or you even hear some noise when you push the car by hands, i think it's too late as it happened to me.

ciao

 

Rifledriver, does positraction additive go by itself from the sump to the satellites inside the differential even if you do not drive the car? If it can, i will buy it.

ciao