Hi guys,

i have a problem with my RX7 FD,

it makes a scratching noise in the first 3 gears when you shift in 4th its gone ,

the noise is only there when you put you foot on the trottle,

also when you put in the clutch its gone, so it must be in the gearbox ?

the noise sounds like a bad diff but it isnt, the diff,

maybe it is a bearing in the box but why doesnt, make it this noise in the 4th ?

maybe somebody can help me thank you,

 

The problem is most likely a bad main bearing in the Trans.

4th should be a 1:1 gear ratio, which is why there is no noise.

 

I agree. It could also be a chipped gear on one of the drive gears, which becomes unloaded when you're in 4th gear.

Either way the easiest solution is to find a good used transmission. I've rebuilt 3rd gen transmissions and it can be done, but usually excessively expensive.

 

Hi guys,

thanks for the help,

the noise is also gone in 5th gear or is that on a other axle in the gearbox like some other cars ?

thanks a lot

 

Check your syncro gears, not sure about the spelling but its the gears that make the gears mesh together. is it hard to put in gear sometimes?

 

Synchros are inactive once you're in a gear. They are just clutches that cushion the instant you push the shifter into a new gear. I don't think it's a synchro.

5th gear uses the same countershaft as 1st-3rd. The only difference is 5th is outside the main gear housing with reverse. If this is a bearing issue, this might agree with hearing noise only in 1-3 because 5th will apply loads differently to the bearings.

Regardless whether you have a bearing or gear problem, the cost for parts begins at several hundred dollars. Add labor. For about the same price and a lot less hassle you can install a used transmission with low mileage. I would focus on finding a good used transmission.

David

 

Hi guys,

no the synchro,s are definatly fine it shift well,

thanks for the help and i agree with degeesaman a used gearbox will be better because i also think it is a bearing,

many thanks