stira2

iTrader: (1)

Hi all, I've taken my box out after some strange grinding/knocking noise I found that the 5th gear cog has lost a few teeth.
The car is a 95 wrx ra with a ty752vb3ea, my question is can I just replace the broken gear and clean the box out?

edsel

iTrader: (2)

Interested in this one. I'm led to believe that the RA boxes fifth gear is held on by a key way that wears out, this key way is smaller than standard boxes? The shaft that holds fifth needs to be reworked before the gear can be replaced. David at API replied with a detailed reply to my last post.

https://www.scoobynet.com/drivetrain...rbox-hold.html

I took the six speed route in the end, sixth gear synchro has just failed on that so it looks like I'm going to need API's services after all.

APIDavid

iTrader: (4)

As Edsel says, have a read of the link and my comments about 5th gear. We can help if you want to go that way.

Sunchro on 4th 5th & 6th has been greatly improved with the carbon coated synchro rings. l'll expect a call then Steve..............

edsel

iTrader: (2)

You will indeed be getting a call, I'm running out of non critical body parts to sell. I'm thinking gearbox out over the winter months.

stira2

iTrader: (1)

Thanks for the info, so it's not as easy as just replacing 5th? What reworking of the shaft is needed? I would love to get it rebuilt by you David but this is performance on a shoe string plus I'm pretty handy with the spanners.

stira2

iTrader: (1)

Any more info on the above?

mechanix

Does 6th only crunch with a high revs upshift. I fixed my crunching 6 speed with an oil change. Use comma SX75/90 GL4.
DO NOT USE GL5. It has too high an EP content. These additives cause the synchro issue.

mechanix

No reason why you cant replace 5th gear. Its an 0.972 ratio on the early RA and prob difficult to find now though. I repaired my old Ra box recently. I replaced the RA fifth with an sti 0.825 fifth. The taller gear makes it motorway bearable.

edsel

iTrader: (2)

Thanks for the reply, I'm willing to try oil change before gearbox strip but ... is GL4 suitable for front LSD's and DCCD trannys? How can a gear oil be GL4 and 5?

mechanix

As far as I know only plated lsd is oil critical. 6 speed have suretrac lsd so should be fine as they are not plated.

stira2

iTrader: (1)

I've got a spare wrx box I could take 5th from is it possible to remove/replace 5th with just removing the transfer case or do I have to split the whole thing?

mechanix

exactly what i did. Used 5th from a spare wrx box. It is possible to replace 5th with just transfer case removed but you need pullers to get the gears off. I split the case and took the shafts out as i replaced 1st synchro as well. Used a hydraulic press as 5th was very tight on shaft.

APIDavid

iTrader: (4)

The oil company that invents an oil that will fix knackered synchro will make millions. Face the truth, the synchro has failed and it needs replacing.

David

edsel

iTrader: (2)

I took advice from a specialist who I have every confidence in and decided to use very expensive fully synth 75w90 all singing and dancing nano bollocks. Crunches terrible when changing into sixth at anything above 1500 revs.
Haven't you heard of liquid engineering