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Hello all,

 

I am absolutely certain I am not the first, nor will I be the last to come on and ask about this particular issue pertaining to these transmissions. However I cannot find a clear answer from browsing other posts and forums, so here goes. 

My '02 Outback wagon has a 5-speed out of an early GD chassis Impreza WRX (Bugeye) installed. I recently had it rebuilt, as I didn't really know what the condition of it was and how many miles it had on it, and I also had the clutch replaced while the transmission was out of the car. For the past little while I've noticed that when slowing down with the car still in gear from about 3K RPM to about 2K RPM it makes this very distinct rattling/grinding noise. I have narrowed it down to a transmission fault as the noise is nowhere to be heard with the clutch disengaged, however what that fault is is somewhat unclear. The most prevalent response has been cheap transmission fluid (which would not surprise me in the least), to other more serious problems. So, I am seeking out help from you all to get a more concrete answer to this question.

Some additional information if this may help with proceedings, the transmission can grind when shifting into first when at a stop (however this is often remedied with shifting into second before shifting into first), it occasionally grinds on the 3rd to 4th up shift (especially if you are or have been travelling at higher speeds, eg travelling on freeways although it does do it occasionally with low speed, in town driving), and very rarely on the 4th to 5th up shift during passing maneuvers. Recently, when the transmission is cold it will make a very loud rattling noise when moving off from a stop in first, and when idling at a stop in neutral. Once the transmission has warmed up a bit after a small amount of driving this more recent noise is no where to be heard. 

Any help on this matter would be greatly appreciated!

Edited by ayykimber

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There is no way to tell what is going on inside the trans without tearing it down. Who did the "rebuild". Sounds like they didn't know their Subaru transmissions well.

 

The only gear oils that work are Subaru HPGO, or Mogul Gear 300. Everything else grinds.

 

Common failure points on the Bugeye trans are center differential, transfer housing bearings, and of course all the teeth ripping off third gear.

 

GD

Edited by GeneralDisorder
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There is no way to tell what is going on inside the trans without tearing it down. Who did the "rebuild". Sounds like they didn't know their Subaru transmissions well.

 

The only gear oils that work are Subaru HPGO, or Mogul Gear 300. Everything else grinds.

 

Common failure points on the Bugeye trans are center differential, transfer housing bearings, and of course all the teeth ripping off third gear.

 

GD

 

It honestly wouldn't surprise me if whoever rebuilt it didn't know what they were doing in the first place. I do know that the center diff was replaced when it was rebuilt. I'm also not running enough power to shear any gears, I'm currently running a SOHC EJ251, very optimistically making at most 150hp, most likely somewhere closer to 120 or so, and the hardest it has to work is on the occasional passing maneuver or on the very occasional gentle off roading I do. I'll change the fluid and go from there. 

 

Thank you for your help! Ill post updates until the problems have been resolved.

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my 06's 5spd ate 2nd gear. I was told the case flexes too much and 3rd or sometimes 2nd gets destroyed.

 

one of the reasons I waited so long to get it back from the shop was, there was ,evidently, some part that must be specified at a point during assembly (a shim? washer?...?) that was sent that was the wrong size. maybe whoever rebuilt your trans didn't get a good measurement on that shim?

 

 

many people report clashing with full synthetic gear lube. NON-synth GL-5 seems the best. There is a walmart synth blend that is cheap and has had some good reviews. At present I have Amsoil Severe Gear in the trans - dunno what it will be like for a full year, but it is a little notchy, but less than the Subaru oil.

 

Best I've had in there was Redline Lightweight Shockproof.

 

Motul has a lot of support, maybe I'll try that in the future. but, really leaning back to the Redline.

 

Temps in Texas may mean our 'best' fluid wouldn't work well in a Kansas winter though!

 

have you pulled your drain plug? maybe the magnet will show you something? (but, it sits next to the diff and some bulkheads/webbing in the trans probably keeps 'chunks' of gear teeth from getting to it)

 

 

 

GD is the expert here, just relating my 5spd horror story - $2100 for a rebuild. under 70K miles, no power mods.

Edited by 1 Lucky Texan

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my 06's 5spd ate 2nd gear. I was told the case flexes too much and 3rd or sometimes 2nd gets destroyed.

 

one of the reasons I waited so long to get it back from the shop was, there was ,evidently, some part that must be specified at a point during assembly (a shim? washer?...?) that was sent that was the wrong size. maybe whoever rebuilt your trans didn't get a good measurement on that shim?

 

 

many people report clashing with full synthetic gear lube. NON-synth GL-5 seems the best. There is a walmart synth blend that is cheap and has had some good reviews. At present I have Amsoil Severe Gear in the trans - dunno what it will be like for a full year, but it is a little notchy, but less than the Subaru oil.

 

Best I've had in there was Redline Lightweight Shockproof.

 

Motul has a lot of support, maybe I'll try that in the future. but, really leaning back to the Redline.

 

Temps in Texas may mean our 'best' fluid wouldn't work well in a Kansas winter though!

 

have you pulled your drain plug? maybe the magnet will show you something? (but, it sits next to the diff and some bulkheads/webbing in the trans probably keeps 'chunks' of gear teeth from getting to it)

 

 

 

GD is the expert here, just relating my 5spd horror story - $2100 for a rebuild. under 70K miles, no power mods.

 

When they did the rebuild the guy from the shop claimed that there were some shavings on the magnet, but on further inspection there wasn't any significant damage to anything, which considering what I am hearing about this shop nowadays makes me reconsider my choice and what he said. However, considering the car itself is sitting around 175K miles (and those haven't been easy miles either considering the car's history, which is another story for another time) and the transmission probably isn't far off of that number as well, the shop just cleaned it up a bit, replaced the clutch, throw-out bearing, and the center diff and called it good. On the subject of lube if I were to go with temp ranges it would be almost impossible to find anything that'll work as it gets to be well over 100 degrees Fahrenheit in the Summers and into the negatives in the Winters, I was looking into OEM lubes like GD suggested since I've generally had better luck with OEM stuff. I will keep your story in mind however should a rebuild be necessary.

 

Thanks!

Edited by ayykimber
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Just pickup some Subaru HPGO from the parts counter. It works very, very well for the price. You will need 4 quarts. 

 

I haven't had any luck with Amsoil or Redline (and I'm an Amsoil dealer - mostly for their engine oil though) in the Subaru manuals. Redline wasn't the worst thing I've used but nothing cures grinding like the Subaru HPGO (formerly Extra-S). Motul Gear 300 is in a class of it's own. It's like liquid silk in these transmissions. But it's $25 per liter.... The STi guys are the only ones that buy it. 

 

I replace center differentials at a rate of probably 4:1 against transmission overhauls. Not just WRX's either. It's all of them even the low power NA engines. 

 

You won't be making enough power to harm the gear teeth on the trans with that engine. But it is a failure point and depending on how it was treated before you got it, they could be weakened. There are stories of people breaking 2nd or 3rd on test drives back in 02/03.

 

GD

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^^^ now I think of it, I had the EXtra-S, flelt notchy/scrape-y in the summer.

 

guess they have something different now - HPGO ?

 

probably worth a look.

 

the tech that did my rebuild felt everything, including the synchros looked fine. said it's just 'bad luck' .....?

 

I dunno what to think, but, this is likely my last manual - I just love the car, can't really afford another 5spd disaster....but, I guess it either happens or not.....

 

 

stupid glass transmission......

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Just pickup some Subaru HPGO from the parts counter. It works very, very well for the price. You will need 4 quarts. 

 

I haven't had any luck with Amsoil or Redline (and I'm an Amsoil dealer - mostly for their engine oil though) in the Subaru manuals. Redline wasn't the worst thing I've used but nothing cures grinding like the Subaru HPGO (formerly Extra-S). Motul Gear 300 is in a class of it's own. It's like liquid silk in these transmissions. But it's $25 per liter.... The STi guys are the only ones that buy it. 

 

I replace center differentials at a rate of probably 4:1 against transmission overhauls. Not just WRX's either. It's all of them even the low power NA engines. 

 

You won't be making enough power to harm the gear teeth on the trans with that engine. But it is a failure point and depending on how it was treated before you got it, they could be weakened. There are stories of people breaking 2nd or 3rd on test drives back in 02/03.

 

GD

 

Thanks so much for the advice, Ill look into some new gear lube and go from there. Hopefully this will cure my problems, and Ill post in this thread what I find for future reference.

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Extra-S and HPGO are two different lubes.  The general consensus on NASIOC seems to be that HPGO is not quite as good as Extra-S was (Can still find Extra-S in Canada, apparently).

 

My WRX currently has Extra-S in it, but I'm closing in on the 30k interval to change it.  My 5 gallon bucket might have enough left for another fluid change, but I'm saving that for my '93 WRX transmission and will be using Motul 300 75w-90 in the '02 WRX. 

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I haven't noticed much difference in the HPGO vs the Extra-S. Both work pretty good. Neither works as well as Motul.

 

GD

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Hey all, 

 

I finally got around to changing out my gear lube, and I have been driving it around for about a month now. 

 

I ended up going with Motul Gear 300 75W90 like GD recommended, and it cured all the crunchiness in the gear box. It is now smooth as butter, and it quieted it down immensely. If you can justify the extra cost It is absolutely worth the extra money!

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