One of the causes of gear box whine Options

[Dr Evil]

I dug into a customers box last night and from the cursory inspection it was one of the cleanest, least abused gear boxes that I have ever been in (from a customer). Most stuff will need some changing around with very little parts replacement. There was no complaint that I know of. Once I removed 1st gear I saw this (IMG:style_emoticons/default/sad.gif)





This is a common cause of high gear whine. In the higher gears the pinion shaft, which is what the lower bearing in the intermediate plate pictured here supports, is spinning at its highest RPM. At this higher pinion RPM most problems with this part of the tranny will become evident. If you have a whine at lower gear and higher engine RPM then you most likely culprit is the input shaft bearing which is the upper bearing in the intermediate plate.

[Dr Evil]

Here are the bearing parts removed. I made a sad face.

[charliew]

In 1977 I tore a toyota 5spd celica down over a xmas vacation with only 36k on it and the botton shaft front bearing was like that. I still don't understand how there can be enough pressure on a cage to make that happen. I think it is shitty heat treating or metalurgy.

[Dr Evil]

Running a gear box dry would assist in this, but I am in agreement that many of the bearings are crap. I particularly hate the input shaft bearing with the brass cages. The cages will shatter if you look at them wrong and if you dont know what you are doing you can replace a broken one with a new one and break the new one during install with out knowing you did. Then you are back where you started (IMG:style_emoticons/default/dry.gif)

[charliew]

I'm sure they made the brass hard to help prevent wear from the balls.

[Dr Evil]

I prefer the steel caged ones, but they are not always available.

[Jeffs9146]

I have this problem on my 6! How hard it this for a DYI??

[Dr Evil]

I have this problem on my 6! How hard it this for a DYI??

It all depends on the Y in DIY (IMG:style_emoticons/default/wink.gif) What is needed?
- Remove the big bolt on the pinion shaft
- Remove all of the shift rods
- Remove the pinion shaft and all its gears
- Remove the castellated nut on the input shaft
- Remove input shaft and all of its gears
- Get the 6 or 8mm 12pt (triple square) tool and remove all of the bots that retain the bearing retainer. This requires a fixture of sorts to hold the int plate while you remove/strip out the bolts
- Drill out stripped bolts (IMG:style_emoticons/default/dry.gif)
- Drive out bad bearing with out messing up the upper input shaft bearing (with the shaft out you have a chance of breaking the fragile bearing.


Installation is the reverse (IMG:style_emoticons/default/wink.gif)

[rick 918-S]

BMW 2002's have ball bearings on the lay shaft that are a weak link. They cause shift problems and are noisy. The trick is to go to the industrail bearing store and have them match the ball bearing with tapered rollers. I had a couple boxes builld for me like that. Worked slick. I wonder if there is a roller bearing out there that could replace the troubled ball bearing.

Balls have very little contact surface and cause "V" shaped pressure on the cage.

[Dr Evil]

For our boxes, the big bearing pictured here is usually ok. It is only now after 30+ years that I am starting to see them breaking. The smaller upper bearing is a different story. They break fairly often, and the bearing size is proprietary to Porsche. I have had people in industry looking into it and no vendors will make the one with the shoulder which is needed for our application. You can find one without the flange/shoulder, but it will not be able to be retained with the stock setup.

[Jeffs9146]

Thanks Dr.!

I will some day begin my tear down and get to the restoration but I am still trying to find the time to begin! Until then it is learn as much as possible!

[abbott295]

Don't know if this idea might be applicable to the "can't find a replacement bearing that' quite fits" problem, but one time I was driving through Mexico in a '72 Datsun pickup that I had bought because I had already found out that you couldn't get Volvo parts in Mexico, but there were lots of Datsuns in Mexico. A wheel bearing went out on the Datsun and I found out that Japanese Datsuns are not the same as Mexican Datsuns.

To get to the point, The auto parts store found me a bearing that fit in the hub and sent me to a machinist (tornero) with a lathe (torno). He turned a piece to fill in between the bearing and the spindle. It worked fine.

So could something like this be done to adapt a roller bearing to replace that ball bearing? But if it only breaks after 30 years, it may not be a big problem? I haven't had that Datsun pickup for almost 25 years.