WRX 6 Speed Conversion Issue
 

Hi, I have recently completed a 6 Speed STI gearbox conversion on my wrx. Everything seems to be fine apart from one thing. I accidentally put the two rear axles in the wrong side left and right so one axel was sticking out of the diff about 10mm but not enough to lose any oil. I swapped them around and fixed them but;

Upon driving in first gear between 1500-2500 rpm there is a vibration that seems to be coming from the left wheel/axel/diff area. It is not present in any other gear or at any other engine speeds. It is nothing severe but is still concerning me. Could the diff have been damaged because of using the shorter axel for a short period of time? Is there any chance the diff is the wrong ratio for the gearbox? Is it just a coincidence that my wheel bearing could have failed at the same time I put these parts in my car? Could it be the r160 is somehow not compatible with my 2006 WRX axels? Specifications:

- 2006 Subaru WRX sedan
- 2007 Subaru WRX STI JDM 6MT transmission
- WRX GD 5 speed pull style clutch
- STI tailshaft
- R160 diff apparently with matching ratios to suit the gearbox.
-2006 WRX axels
-DCCD controller NOT currently installed
- Wheel alignment completed

Part number of gear box ? = check gear box codes on here
Check final drive / step down ?

You could use your own old diff centre in the new diff that would resolve any fitment issues with the axels

I all ways take the rear cover off the diff and confirm the ratio. Also confirms the condition of the diff internals

Thanks for your reply, I’ll cross check the ratios between the box and diff but if they weren’t matching I’m sure it would be really noticeable. If not I guess my best option is to swap the diff centres?


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Take you old diff centre out the diff

Fit this to the ratio in the diff you purchased

Fit your old axels

Ensure you have the C clip in the diff centre or on your axel

Also have you done a bolt check ?

Okay thanks for your help, there is no C clip on my axels so there must be C clips in the diff? could it be possible one C clip is out of position on the left of the diff? I don’t think the diff is broken otherwise it should perform badly at most rpm’s and all gears instead of one gear and for only a bracket of 1000 rpms. (1st gear 1500-2500 rpm) What is a bolt check? Thanks a lot for your help so far I really appreciate it


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Go over the bolts you have have removed and check there tight. Mark each one as you go so you know you have done it.

What is the code on your gear box ?

It's near the starter motor

Okay, the code is

DS- TY856WB7KA

I checked this and it seems to be from an 07 STI which is what the seller told me

I will check all my bolts and see if they’re tight.


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So your rear diff would be a 3.54 ratio