are my synchros / trans going south?

[moribundman]

Most German transmissions make a "turbine" or spooling up sound, which is normal. If the noise appears to get worse, it could be your perception or it could really be happening. A droning or whining noise that occurs only at certain speeds or in certain gears indicates a damaged transmission bearing, for example the main shaft bearing. A rattling, chattering, or rough noise indicates chipped teeth. Shifting down into first gear while still moving without good reason (steep SF hill and engine breaking)is generally not a great idea and I would avoid it. On an off-chance, the old BMW does definitely have a fully synchronized 1st gear, right?

If I were you, I'd change the transmission fluid and I'd also examine the old fluid closely. I found some interesting bits and pieces in mine.

 

[mechtech]

Pick which symptom you'd like to dianose, and I'll do my best.
Realize that because they are inconsistant and opposite, I will give different opinions on what is wrong.
Kind of like an umpire - if you are calling outside pitches strikes, be consistant.

 

[JohnBrowning]

I have never heard a syncro ever! I would imagine that your transmission is a Synchromesh style of transmisson as almost all of you modern transmission are today! You might review how they work as they are much different then transmission of 15 years ago.

I would also susgest that you are hearing gear whine or a bearing going bad!The noiset thing in a manual transmission is the bearing that the shafts ride on especialy the main shaft!

 

[LarryL]

quote:

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You might review how they work as they are much different then transmission of 15 years ago.

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...what

 

[LarryL]

I keep cars a long time and put a lot of miles on them. One thing happens to every manual transmission that is used carefully and packs on a lot of miles. The bearings wear out (roller bearings are contact bearings and just wear out, no matter what type of oil you use) and the gears and syncros are in excellent conditions. You replace the bearings and seals and get your quiet transmission back. I have a Honda Civic with 376k+ miles and did the transmission at just over 200k. The noise got loud, changed it's tone several times and came and went, then stayed. Well meaning friends said it needed a T/O bearing, a first motion shaft or just replaced in total. When I pulled it out, I could see wear on several bearings, but the gears and syncros looked brand new. The Honda dealer said the only way to fix it was to replace the gears too, wrong. I had to go to a jobber to get the bearings and seals. That fixed all the wierd noises and I could listen to the radio again, at reasonable volume levels again.

 

[skate1968]

quote from LarryL--
"I keep cars a long time and put a lot of miles on them. One thing happens to every manual transmission that is used carefully and packs on a lot of miles. The bearings wear out (roller bearings are contact bearings and just wear out, no matter what type of oil you use) and the gears and syncros are in excellent conditions. You replace the bearings and seals and get your quiet transmission back. I have a Honda Civic with 376k+ miles and did the transmission at just over 200k. The noise got loud, changed it's tone several times and came and went, then stayed. Well meaning friends said it needed a T/O bearing, a first motion shaft or just replaced in total. When I pulled it out, I could see wear on several bearings, but the gears and syncros looked brand new. The Honda dealer said the only way to fix it was to replace the gears too, wrong. I had to go to a jobber to get the bearings and seals. That fixed all the wierd noises and I could listen to the radio again, at reasonable volume levels again."

Wow, Larry that sounds VERY SIMILAR to the noises i'm hearing from my 91 civic SX! Geez I been googling for some time trying to gain some insight as to how long my transmission was going to last. The people here were very very helpful with my oil sludge/burning questions. But i didn't expect to find such detailed discussion of transmission on this Oil site! Pleasant surprise! You can bet that i'll be posting a lot of questions later today.

Thanks to all who contributed to the above discussion.

 

[skate1968]

Ooops. ...my 91 Civic DX