[vliegwielolaf1234]

Her is the thing , also see my other topic IRRITATING NOISE MHHHHHHHH .



I think i have done everything i can about indentifying the noise , and i am 99.9% convinced it is the gearbox making the noise .



There is only one other option and that would be the transaxle , but is would have been making the same noise in all gears and not just speed dependant , let me know if i am wrong .



option 1 is to replace the gearbox with a used one(no <acronym title='Limited Slip Differential'>LSD</acronym>) , i found 4 used ones price from $1500.- unknown history , 2x $2700.- about 120000km . and an other one $3300 did not ask for the history yet .



Option 2

Rebuilt no <acronym title='Limited Slip Differential'>LSD</acronym> $3500 (exchange part )

Also ifound 2 with <acronym title='Limited Slip Differential'>LSD</acronym> , one $3500,- did not ask for history yet .(exchange part)

And the other one rebuilt original unit with <acronym title='Limited Slip Differential'>LSD</acronym> price $5000' (exchange part)



I am on the list for a SC so the plan is to make more power , so is the <acronym title='Limited Slip Differential'>LSD</acronym> a really nice option to have , i am not going drive it on the circuit and if i do so it would be a one time event .

Done my part of racing , and stil am but on motorcycles and only offroad .



Anyway any sugestions are welcome , money is always an issue because i rather spend it one other stuff , but if something is broken or is going to break down i need to do somthing about it .



I let the oil out the gearbox today , there are some metal parts visible in the oil some gold and some silver

And the car is difficult to shift when cold .

Sometimes i have to put it in a 2 gear first to get it to go in reverse or 1st when cold .

Rev maching is the way to go when downshifting .

It has never been the smoothest gearbox , but can not compare with a different 968 , if i compare it with my volvo it is not way as smooth as that car .(6 speed manual gearbox )

The noise that is the main thing wich bothers me the most



So any suggestions wich one " used (is it worth the risk ) 2 of them are from accident cars no <acronym title='Limited Slip Differential'>LSD</acronym>



REBUILT



NO <acronym title='Limited Slip Differential'>LSD</acronym> REBUILT





REBUILT YES <acronym title='Limited Slip Differential'>LSD</acronym> i have to have it , it makes the car way better



Or get my own gearbox rebuilt ? and maybe ad a <acronym title='Limited Slip Differential'>LSD</acronym> .(price <acronym title='Limited Slip Differential'>LSD</acronym> 1500+ rebuilt costs?)



Or keep on going ?

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[tamathumper]

I wish I could help, but I don't understand what kind of noise is spelled "MHHHHHHHH". For once, I am not trying to be funny, I really can't understand what that sound is from the spelling of it.





In the past I've had failed wheel bearings, and even a failed rear mainshaft bearing in my 924, but they made sounds I would call a "roar" or a "rumble", and which I could pinpoint by turning left or right, or by hearing it all the time regardless of direction.



For me personally, I would go with rebuilding the gearbox I had and I would add an <acronym title='Limited Slip Differential'>LSD</acronym> unit to it (there are plenty of threads and opinions here about the different options available and their pros and cons). I don't like buying big expensive gear boxes from wrecked cars, because I don't know what damage could be inside them. I hasten to add that is my personal opinion, and others' may differ (and perhaps soon will).



I do hope that you get your problem sorted, and I'm sorry to not be of more assistance.

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[vliegwielolaf1234]

It is more of a moan i guess .



Rebuilt is probably the best way to go , and ading a <acronym title='Limited Slip Differential'>LSD</acronym> is i nice option to have .

It also comes with 1 year waranty .



I just want to make sure i don't change the gearbox and still have the sound .

On the other hand i did find some metal flakes , so something is going on .



thanks for the response .

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[tamathumper]

Well, some metal flakes is normal, there is a *lot* of force on basic metal-to-metal contact surfaces, after all. The amount is what's important, and I look at it like I'm panning for gold... By that I mean, if I were panning for gold and I'd be excited about the amount of metal I found, that's bad. <img src="/forum/images/smilies/968/wink.png" class="smilie" alt="" />

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[vliegwielolaf1234]

[quote name='tamathumper' timestamp='1327362069' post='120824']

Well, some metal flakes is normal, there is a *lot* of force on basic metal-to-metal contact surfaces, after all. The amount is what's important, and I look at it like I'm panning for gold... By that I mean, if I were panning for gold and I'd be excited about the amount of metal I found, that's bad. <img src="/forum/images/smilies/968/wink.png" class="smilie" alt="" />

[/quote]

Gold it is , i think there is to much metall in the oil , so there is a bearring going bad , and sunchro's need attention as well .



I think i'll go with the Germans and swap the geardox for a rebuilt one , about a 1000$ extra for a <acronym title='Limited Slip Differential'>LSD</acronym> , wich souds like a good price to me .

It will be a original <acronym title='Limited Slip Differential'>LSD</acronym> , wich woiuld be fine for street use .

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[jaap]

Hi Olaf,



When my gearbox developed the pinion bearing problem the opc in trying to fix it (although I already told them it was the pinion bearing) first replaced the differential bearings. They did this with the gearbox in place and I think these bearing are where the drive shafts connect to the gearbox/differential. Although this did not solve the pinion bearing noise it fixed a humming sort of noise that I sometimes noticed at specifc speeds and actaully thought came from the front of the car. Because it did not fix the pinion bearing noise they only charged for the parts but not the work which I think was reasonable. Of course they made up for it when replacing the pinion bearing <img src="/forum/images/smilies/968/smile.png" class="smilie" alt="" />



Jaap

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[steven74]

Gold must be brass from the sychronizers. This makes sense if it is hard to shift between gears and makes a crashing noise. I thought the first gear on these cars gave problems. I say rebuild what you have. At least it is a known issue and it hopefully is just sychros and maybe a gear as well as bearings and seals. <acronym title='Limited Slip Differential'>LSD</acronym> is always nice to have too, esp. with a supercharger planned for the future. Good luck.

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[DaveN]

Syncros are definitely gone, brass in oil. Getting a used low Km gear box means you are taking a chance on the pinion bearing again. If it's a higher mileage trans then the pinion is probably ok as it develops earlier on but then who wants to load a high mileage trans with a SC <img src="/forum/images/smilies/968/sad.png" class="smilie" alt="" />

I would go rebuilt with <acronym title='Limited Slip Differential'>LSD</acronym>, that's my next expense as I break free in corners too often with the SC.

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[vliegwielolaf1234]

Thanks for the reply's .



This is what is going to happen , i have a gearbox waiting for me in Germany (freisinger motorsport) .



It is completly rebuilt and i have to pay an extra 1000$ to get a <acronym title='Limited Slip Differential'>LSD</acronym> in there , and i can chose torsen or ZF , i think i'll go for the torsen since i will not use it on the circuit and needs no maintanance ?



Will be near them anyway next week so i'll might as wel get it done , and can't wait to drive the car without the background noises .



Other thing is the central drive shaft i need to check those bearrings , if i disconect it from the clutch , i should be able to spin it by hand to find out if the bearrings are in good shape , any other ways to check ?

Don't want to hear any noise after i finish this job !!!!!!

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[vliegwielolaf1234]

Gearbox is out , easy job , took about 90min , 2 man job to carry that is for sure .



could feel some play on the input shaft , wich i think sould have none .



Saturday i will pick up my rebuilt one , hope to install it on monday .



.

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[tamathumper]

Play tangentially, or axially?

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[vliegwielolaf1234]

Fresh rebuilt , ready to get installed hopefully tomorrow .

Final price for the rebuilt unit including the torsen <acronym title='Limited Slip Differential'>LSD</acronym> wich i did not have before (exchange) , 4200$ . got a bit of a discount <img src="/forum/images/smilies/968/clap.gif" class="smilie" alt="" /> <img src="/forum/images/smilies/968/clap.gif" class="smilie" alt="" />













   



The people where i bought the gearbox told me , use the adviced oil from the factory 75w90 or a higher number would even be better he said , 100 or even 120 would be no problem and would be the thing to do , wathever you do don't change to a lighter oil .

The same for the engine he said , a lot of problems come from to thin synthetic oils ,these old cars are not made for that , they like thick mineral based oil's

He also had a couple of 951's , they actuallly got mobil to make oil at the old spec's , and they had no more problems with these cars ,they had a lot with newer oil's

Man they had al lot of stuff there , 12 cilinder porsche racing engines and the car's to go with it .

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[tamathumper]

When I bought my car, there was a big note stuffed in with the service records. It said "Never use synthetic oil, and fire any mechanic who recommends it!", in great big, black hand-written script...



I guess the previous owner must have had a bad experience with it, eh?

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[Langley968]

Waiting to hear some of the "experts" chime in on the last two posts...

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[vliegwielolaf1234]

HIHAAAA , yes .



Really happy the noise is gone , it was the gearbox as expected .

MAN WHAT A NICE CAR TO DRIVE .

It was kind of hard to get up to 100kmph since i live kind of outdoors , and the roads around my house are coverd in snow and ice .

But yes it's quiet no more noises and de <acronym title='Limited Slip Differential'><acronym title='Limited Slip Differential'>LSD</acronym></acronym> is really making the car better to handel . did not expect it to be such a + to have .

The car is never been better since i had it , also it shifts like a sports car direct with postive input , it has always been kind off sluggish before , difficult to say before if

it should be different if you can't compare

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