Gearbox issue, what to do best….

[minijojo]

got a 61’ RHD saloon with 948 engine and 948 gearbox. (i´m sure with the model and the engine….)
I get the feeling that the noise in first and reverse gear getting extreme louder. All others sound quite normal.
I know that first and rev gear don’t have gaerteeth diagonally, that is why they are always a little noisy.
Now i´m thinking how to proceed.
Looking for a exchange gearbox? get the installed one reconditioned?
When looking for an exchange, only 948 gearboxes will fit?
Looking forward for tips and hints

[philthehill]

As a straight swop the 948cc gearbox will only fit like for like.
If you take it to the next stage and fit a 1098cc rear engine plate, flywheel and clutch assy you can utilise a 1098cc gearbox whilst your 948cc gearbox is overhauled.
Food for thought.

[bmcecosse]

Just be careful when using 1st (get it rolling - then straight in to 2nd) and reverse - it will last for ages.... I assume there is oil (SAE30) in the gearbox. If the other 3 gears are working well - seems a shame to spend a lot of money and effort changing the box.

[minijojo]

thanks, good advices.
will try a first step by oil exchange with SAE30. The oil was filled up after changing the sealing ring to the propshaft. But don't know what kind of oil the mechanic filled in.....
Now wether is better and i can do it myself (guess, it´s most times the better way to go)
I use the first gear only for the first few meters after stop and i don´t drive max speed in reverse mode...

[minijojo]

let me tell you how this goes on.
did the oil exchange with SAE 30 last weekend. About 150 ccm were missing.
Testdrive shows no differences in noise level for first and reverse gear. It seams the noise level in 4th gear at „high speed“ is a little bit reduced.
So now my new questions. Is this more a matter of shaft bearings or are the gear wheels for fist and reverse damaged?
2nd to 4th gear running noise seems normal to me.
Any hints welcome
regards
Joachim

[bmcecosse]

Gear teeth damage.....

[minijojo]

thanks for your tip.
I feared it,
will have a look for a place to remove engine and gearbox. Not a work for doing it on the road now.
I did that with my beetles 40 years ago, but that were other times.....

[bmcecosse]

As before -treat it carefully and it will run for years.