WRX Transmission woes- 5th gear syncro gone

[ehansen007]

Well this sucks. Took it out for a nice spin to the car show and now I can't get the thing into reverse. I was having a hard time down shifting from 4 to 3rd and it wouldn't stay in 5th. I've tried everything to get it into reverse. Even manually without the linkage. Think I'll have to crack the case open? I've read everything from reverse check sleeve to bent shifter fork. Ugh.

[wallace18]

Do you have an idea of how much torque your electric motor is making? Since it is full torque right away the trans may not be strong enough VS a gas engine that builds torque.

[ehansen007]

It's making 185 lb/ft from 0-5000 RPM. What would it have broken or worn out so quickly ?

[wallace18]

It's making 185 lb/ft from 0-5000 RPM. What would it have broken or worn out so quickly ?

Till you open it up it is all just a guess.

[Mechie3]

Do you know the history of the trans?

Someone else mentioned it wouldn't stay in gear and the culprit was the locking sleeve and rear nut weren't torqued well enough.

[ehansen007]

So this is what I've found so far. In my case it could be one of two things. The previous owner may have changed the 5th gear out and not tightened down and not dented the nut collar into the detents in the shaft so it basically came loose destroying the syncro. With the nut at the end of the shaft it basically could not get in reverse nor could it stay in 5th. My other theory is that the lack of oil in the rear of the case (due to my angle of install) heated up the syncro so much, it expanded the nut, negating the dents and spun off. From this photo you can see that there is no oil on the syncro and that it appears to have had some heat issues. I'm picking up a newer transmission and I plan on double checking the main nut before putting into use. The new syncro setup would have cost about $250-300 and I wasn't sure if there was any other damage. I plan on cracking that case and seeing if anyone has an old 5th gear from a swap project that I can put into the old one and then sell it or keep it as a spare. I hope I won't need it!

[Bob_n_Cincy]

My other theory is that the lack of oil in the rear of the case (due to my angle of install) heated up the syncro so much, it expanded the nut, negating the dents and spun off. From this photo you can see that there is no oil on the syncro and that it appears to have had some heat issues.

Is it possible the center diff would sling oil up onto the fifth gear synchronizer?
Maybe we need to add a arm to the 2wd adapter that will sling oil to the top of the case.

oil slingers.jpg

IMG_20130427_062858_zps2bbfd72f.jpg

This little oil catcher in top the case sends oil to the center of the input shaft. Does anyone know where that oil goes?
Bob




Bob

[RM1SepEx]

The center diff displaces a ton of oil, I think it is very important to have the proper amt of oil...

[Bob_n_Cincy]

The center diff displaces a ton of oil, I think it is very important to have the proper amt of oil...

With my car level, the center diff was only 1/4" deep into the oil.
Bob

[ehansen007]

Yeah, good input Bob (as always). Yesterday was an interesting day for sure. I had found a transmission on Craigslist and spoken to the guy and it turns out he had a few; one of which was a modified '03 that had 30K miles and one chump car endurance race on it. Turns out they had to convert to it 2wd and had made their own coupler! It's also got the stainless steel output shaft on it which was a plus. I spoke at length with the guy and he races and works on Subies all day about durability and torque and really knew his stuff. He was also the only one that knew what caused my issue (including the dealers!) . In end the end he set me up with a heavy duty throw out bearing which his father makes for racing WRXs and BG ultraguard oil which he swears by. And to your point Bob, this oil has a component that helps sling the oil about the case so it doesn't just sit in the bottom of the case. He also told me to fill it with all 4qts to make sure the back gets enough but I like your idea too.

So I brought that dirty little beauty home with me last night and proceed to put some elbow grease into it and take off the tail housing to put the backing plate on it..

One thing I noticed on both transmissions is that when I pulled off the tail housing, the bearing races were sitting there. This is something most builders are not going to think about when removing the center diff assembly (like me) and that is that center diff has a race at the back end of the case that will not come out on it's own but apparently with some heat it releases. It looks like it will just sit in the tail case without entering the 5th gear area but why take the chance? I've pictured it below.

[STiPWRD]

One thing I noticed on both transmissions is that when I pulled off the tail housing, the bearing races were sitting there. This is something most builders are not going to think about when removing the center diff assembly (like me) and that is that center diff has a race at the back end of the case that will not come out on it's own but apparently with some heat it releases. It looks like it will just sit in the tail case without entering the 5th gear area but why take the chance? I've pictured it below.

Definitely a good idea to remove that race. I didn't notice it at first either but it fell out when I was handling the rear housing.

[Bob_n_Cincy]

Definitely a good idea to remove that race. I didn't notice it at first either but it fell out when I was handling the rear housing.

Actually, you should remove the race and the big bearing below it. They both fall out.

race.jpg

Another thing I noticed is that there is a hole that flying oil would go into to lube the shifter shaft.
Without the center diff, this won't happen. I am going to put some red grease on the shifter shaft.

Bob

[ehansen007]

Nothing like the ole "aerosol overhaul!!!" Let's hope she better than the last.

[stack]

Nice Work E.

stack