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BN2 gearbox question

curtis

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The gearbox is a little noisy on over run and generally in 1st gear. Until I take it out for a check would a change of oil type help?
I am running 20/50. Would something like a straight 60 be better?
 
I'm not sure what you mean by "over-run". Do you mean overdrive? 1st gear is a straight cut gear and makes more noise than the others even when in top shape. I find first gear too low for my flatland driving and I never use it. If the car doesn't pop out of gear and the gearbox filter is not full of metal it may be normal. Overdrive noise is not normal. You should not really hear much of a difference between 3rd and 4th with, or without OD engaged. There are many threads in this forum about gearbox oil. Do a search and see if you can figure out what oil you want to use. Most folks seem to use either 30wt non detergent oil or MTL redline product.
 
curtis.

Ii know what you mean by overun but why do you do it or let it happen especially in 1st gear.

One of the main reasons for the noise is the fact that the case hardening on the 1st gear of the cluster gear usually wears away and leaves the teeth of that gear looking pockmarked. When this happens the same thing happens to 1st gear on the mainshaft.

Any noise on overun in any of the other gears is probably caused by worn syncro's.

Another cause could be excessive end float of the cluster gear due to wear of the thrust washers.

As far as putting in heavier oil you're just trying to ignore the problem but if you want to do this then try some banana skins as I've heard they sometimes work well.

These gearboxes are generally quite reliable and will go for ages with any of the above problems mentioned and with very little attention. About all you really have to do is check the oil on a regular basis and with a BN2 it's easy to do that anyway (compared to a BN1 that is).

regards

bundyrum
 
Thanks for the comments. Didn't realize that 1st gear was straight cut. Learn something every day !
I wasn't too clear about over run. I mean decelleration.
And no I don't do that in first gear,it's just for moving off,and then very quickly into second.
It's not that I want to ignore the problem it's just that I won't be able to do anything about it until later in the year and I thought about the heavier oil.
 
Have to use my 1st to move the big brute... it is fine, just a bit of a typical straight cut gear wine, unless i am leaving my driveway and have to stop for traffic... letting off on the accelerator while in first creates a sound that would wake the dead (my passengers have always said 'oh...that doesn't sound very good')... anyway...the rest of the gears are quiet and all seems to sound right (that old english transmission sound anyway).
 
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