Additive against transmission noise (915) YES or NOT?

[Muf]

Would you give some additive into SWEPCO 201 to prevent the transmission (especially 5th gear) from whining?

I have no problem with the synchros, can easily shift from 1st to 2nd even when accelerating hard (the 2nd synchro ring has been replaced two weeks ago). There was even an axial play on a bearing which was fixed when the tranny was out of the car. But it still whines when cruising around 90 km/h (55 MPH) and accelerating on the 5th. All the rest about my 915 is fine.

Since 80 - 100 km/h is the speed I go most often and the 5th gear seems to be strong enough to handle even lower speeds I am using this combination all the time. But the noise really bothers me.

Any recommendations?

[livi]

Hi muf,

Happy to see yet another European on this forum !

I have the same "song" in my transmission. Generally I donīt think the experts here (not me, mind you) recommend any additives.

[Bill Verburg]

an additive isn't going to stop the whining. I don't know what might cause it, I don't recall any particularly loud 5^th gear whine in any of the 915s I've had or driven

Is the fluid level correct?

[john walker's workshop]

sawdust. a couple handfuls and it quiets right down. (humor). 5th tends to get worn from lack of oil. it's the first to suffer when oil leaks cause low oil level.

[livi]

John,

I am always relying on your opinion, but, sawdust - I presume thats a joke ?

[john walker's workshop]

hell, the old timers used it, especially when they wanted to sell the car. then there's the 140 weight third member oil trick. it did quiet the gears, but the shifter felt like you had cold molasses in there. don't try this at home.

[RoninLB]

coffee beans also works well in a noisy differential.

[Muf]

I do not know if some previous owner ran low on tranny oil but I am sure now there is enough (just a milimeter below the filling hole).
I am so desperate I might try the sawdust :-)I'll let you know whether it worked...

[TRE Cup]

There is an additive available in the states from the Ford dealer. It is compatible with limited slip or open differentials. It actually has helped some clients'cars with noisy transmissions. it smells terrible, but is inexpensive (less than $10 per bottle- only one needed) and it might help. It is called Additive Friction Modifier part number 137219 or XL-3 and sold under the Ford Motorcraft brand name

Of course it will not make gears or bearings "new" again, but it couldn't hurt to try it

[krauthead]

I've always heard the alternative to sawdust is a couple of bannanas. Of course this only works on third members. Maybe some other fruit for trannys.

[donstevens]

Muf,

Live with the noise. Additives alter the chemistry of the original oils and often make the whole system less efficient and create more wear than oil alone.

You mentioned that you had a bearing replaced. While the old bearing was in there the gears wore in relation to the slop that was there. You fixed the bearing thus realingning the gear to their orginal position and now the unusual wear pattern is what is causing the whine. Most likely, there is no problem here and based on the way you mentioned the car shifts, it sounds like it will be a long long time before you have to open up that box again.

You best bet is to "deal with it".

Don

[Muf]

Don,

The whining was there even before the rebuild. I hoped that it would improve it, but unfortunatelly...
And the bearing was not replaced, just adjusted...

I think I can live with a bit more wear than optimum, I am not going to drive more than 2 thousand miles a year. What wear could that be? But I will drive most of them in the rev range when the 5th gear whines :-(

[donstevens]

Originally posted by Muf
Don,


What wear could that be?

I don't know honestly but at 2000 miles per year it won't too bad.

I still say no additive. Change the fluid every other year and have the oil analyzed. This way you can see how much metal accumulates on the drain plug and the oil analysis will tell you how much iron (in parst per milllion) is in the oil. You might find it is not all that bad and more annoying than damaging.

Good luck,

Don.