Help with 5.1 Final drive

[skunk2_dc5]

Hi felas,

This i think is for the ones with experience with aftermarket final drives! This is not about my car but for a friend who has recently installed a 5.1 final drive and he asked me to forward this to you to get some help.

Well the problem is that after installing this final drive he has got a loud buzzing sound coming from the gearbox. He already knew that this was somewhat normal but this sound is too much he says!

Is this loud buzzing normal?

also what kind of transmision oil should he be running with this final drive because he is running the Honda MTF and the mechanic told him that it will need thicker oil.

thanks in advance

 

[rascal69]

Hi felas,

This i think is for the ones with experience with aftermarket final drives! This is not about my car but for a friend who has recently installed a 5.1 final drive and he asked me to forward this to you to get some help.

Well the problem is that after installing this final drive he has got a loud buzzing sound coming from the gearbox. He already knew that this was somewhat normal but this sound is too much he says!

Is this loud buzzing normal?

also what kind of transmision oil should he be running with this final drive because he is running the Honda MTF and the mechanic told him that it will need thicker oil.

thanks in advance

A very loud whine/buzzing means something is not right. mines used to whine alot (mfactory 5.46) and i got it rebuilt again after 1k miles as it broke a driveshaft and knew something wasnt right. Mines is now very quiet and very little noise. Which i was told by mfactory is right and i havnt had any problems since. I also have honda mtf in my gearbox.
My gearbox spec is
mfactory 5.46 fd
mfactory carbon lined syncos
mfactory lsd.
And i havnt had any problems using honda mtf in it. First time i using the gearbox oil recommended by mfactory. Cant mind the make but that also was a mtf oil.

 

[skunk2_dc5]

thanks for the answer

 

[blueguy]

I have a 5.1 FD and there is no buzzing noise at all.

 

[coyote_dc5]

Sorry to jump on this thread but what top speed on each gears do you get with a 5.1 FD? Presumably one would do such a mod to increase acceleration? What is the standard FD?

 

[C&S Evo7]

should be no extra noise, the 5.1 is usually the shaft from a crv so should be honda quality, the oem oil is perfect for all but heavy race use.

 

[paul hughes]

through measuring these we have discovered two different gear pitch helical cuts for the Honda 5.1 cw/p and counter shaft pair, if you mix them up they whine and buzzzz just before stripping the teeth.

If you have only changed the large diff gear(called crown wheel) and not the actual full counter shaft throught he box it will do this....if you have bought the set second hand then another beware.

if this is the case change it asap imo.

 

[C&S Evo7]

like paul says, they should always be changed as a pair, people think it is just the shaft from the crv you need and indeed on its own it wont fit properly and will cause a problem

 

[skunk2_dc5]

the problem was found to be the standard bearing! the FD kit came came with the CRV bearing, however the mechanic who did the job kept the standard bearing instead of installing tnhe whole kit together with the bearing that was supplied! as a result the standard bearing was a bit smaller causing the teach of the shaft to catch and make that noise!

 

[C&S Evo7]

ah, sounds plausible. glad its sorted.