1971 911 Transmission Bearings Races Loose

[denniso]

Hi All,

The pinion and main shaft bearing races in my '71 911 5-speed transmission case will spin with some effort. I've read the 915 transmissions have this problem and the case can be machined to address and fix the problem. I've not been able to find a fix for the 911 transmission, other than find a new case. Is the case junk or can it be repaired like the 915 transmissions?

thanks
Dennis

[Jon B]

Hi Dennis,

The two bearing bores in your mag case were machined into an iron web. You could have the bores machined & sleeved, but unless the bearing shells are very loose it'll probably be fine for many years of likely limited driving.
I've never seen the mag cases, with their iron webs, having worn bearing bores as bad as the later 915 aluminum cases.

Jon B.
Vista, CA

[Richy]

Nice , my answer would be the same as Jon's , but now not required . I inspected 4 cases for my car , non of the bearing bores were really tight , so if your races require some effort to turn you are good to go .

[denniso]

Hi Jon, Richy,

Thanks for the great responses. Do you recommend using loctite or leave as is?

Thanks,
Dennis

[Jon B]

Do you recommend using Loctite... ?

No, it wont hold the bearing shells, and will end up as flakes floating in the gear oil.
Just clean everything and put the shells in dry, or with some oil if necessary. They'll get oiled anyway.

Jon B.
Vista, CA

[denniso]

Thanks Jon.

I won't be using loctite. I didn't think about it flaking off - good point.

Dennis

[stephers]

What about the green loctite? Isn't that is what is for?

[Jon B]

What about the green loctite? Isn't that is what is for?

I think you're referring to Sleeve Retainer, which is green, and not green Threadlocker, but in my experience neither will adhere to a bearing shell for long.
But he can try it.

Jon B.
Vista, CA

[AKAMick]

I think you're referring to Sleeve Retainer, which is green, and not green Threadlocker, but in my experience neither will adhere to a bearing shell for long.
But he can try it.

Jon B.
Vista, CA

I have never used loctite bearing retainer in a Porsche gearbox but have used it in Rockwell rear axles for heavy trucks where it did the job it was intended for, the bearings in those trucks never spun again, in fact during further reconditioning years later proved to be retained so well that they had difficulty removing them.

[gled49]

In the 915’s that the bearing is still snug and doesn’t rock in the bore I stake the race with a 1/8” roll pin. The groove in the race and case are blind hole and the clamping plate retains the other end of the roll pin. Not sure if anything like this would work on a 901/911.