+2.9 GST Motorsports
 

A much belated thank you to the folks at GST. This happed several months back, but it took a while for me to feel comfortable with the new differential (it still makes some noises at times, but it's just about gone...worlds better than it was before).

Anyhow, here's the story:
I took my 05 STi to GST for a 30k tune with synthetics and to upgrade parts. Everything was done perfectly (+1) except for the rear differential, which started making grinding noises on tight turns from a dead stop. It was something that happened during that tune but I'm not convinced that it was (all?) their bad (more on that later).

Worried, I scheduled another appearance with Greg and brought it over after work. A few techs and I went for a test drive and confirmed my suspicions that it was the rear diff. Upon getting back to the shop, they drained the fluid to see if anything was wrong with it (which there wasn't) and replaced it with synthetic, all for no charge (+1). They suggested that the best solution would be to take it to the dealership since it was still under warranty. This is where it gets a bit hairy.

I took my Suby to Livermore Subaru one morning shortly after and determined that since synthetic fluid was put into the differential, it voided the warranty for the differential and they could replace the rear diff for $2k+. They somehow determined that the synthetic fluid broke it even though all the tech did was listen to it. Not sure how you determine that by the sound alone. The tech must have had some amazing ears. This all took me by surprise and I told them to hold off on the service. I called GST and Greg and Mike both told me that they've never heard of this problem being caused by synthetics. Just to get a third party opinion, I called Redwood City Subaru, where I purchased the car and have a rather high opinion of (though with limited experience...they're too far from where I live). I just asked the tech there if they would recommend putting synthetics in the differential of an STi and they said they would not since they've seen several problems arise from it.

I called back Livermore and asked if there was any documentation regarding synthetics in the differential. They said yes and when I went to pick up the car, they showed me in the owner's manual the oil grades acceptable in the WRX and how the STi is different. However, the synthetic oil that GST used fell within the guidelines outlined in the owner's manual. To be fair, I have to subtract 0.1 since it seems that dealerships are in consensus regarding not putting synthetics in the differential, but I can't justify faulting GST anymore than that since if it's not documented...then...well, how the hell would GST know what the dealerships are thinking? They're not psychics.

I called Mike back and told him what was up. He offered to replace my rear differential for labor ONLY, which would be 10x cheaper than the $2k+ quote I got from the dealership. I set up a date and Mike honored his offer.

Both Livermore Subaru and GST Motorsports thought the other one was at fault, but the difference was that Livermore Subaru kicked me to the curb while GST Motorsports took me in under their wing. So...a HUGE +1 for Mike and the rest of GST.

Thanks again (and sorry for all the annoying phone calls) to Mike and Greg...and to the guys behind the scenes there. Because of you guys, I'm no longer afraid of making right turns or u-turns and hearing grinding noises.


PS. The guy at the front desk/sales at Livermore Subaru seemed to be a nice guy. If Livermore did indeed feed me BS, it didn't come from him. It was obvious he was just relaying information to me. He had a "we'll take care of you" demeanor when I first told him of my situation and when he told me they couldn't honor the warranty, he seemed apologetic. Just wanted to make sure I'm not shooting the messenger.

edit: Just in case I wasn't clear before, the dealership doesn't recommend synthetics in the differential for STis (unsure if it's year-specific). They said it's okay for WRXs.

[QUOTE=CluskillZ;2218566]
However, the synthetic oil that GST used fell within the guidelines outlined in the owner's manual.[/QUOTE]

What brand fluid? It might be good to point out so readers could possibly avoid using it.

Sucks to hear the dealership wouldnt honor your warranty even though you followed the specs in the owners manual (grounds for a lawsuit maybe?).

Did you buy your car used? Drove it hard? Those R180 rear diffs are pretty tough.

This is the first incident where I've heard about synthetic in the rear diff to cause problems.

GST does have awesome customer service.

Good read.

[QUOTE=03_Impreza_Al;2220394]
Those R180 rear diffs are pretty tough.

This is the first incident where I've heard about synthetic in the rear diff to cause problems.
[/QUOTE]

Ditto, I frequent the boards often (iclub, nasioc, iwsti) and havent heard any STi owners having drivetrain problems unless they are launching on DR's (broken axels) or just plain abusing it (endless donuts on tarmac or clutch dumps in reverse).

[QUOTE=subie OCD;2220275]What brand fluid? It might be good to point out so readers could possibly avoid using it.
[/QUOTE]

From an email from Greg: Redline 75-90 NS Gear Oil
I'm not sure if that's bad oil to use. Greg said that they always use that for the diff when using synthetic oil. With all the Subys that roll in and out of that place, if the oil really is the culprit, they should be getting a ton of complaints.....right? But that doesn't seem to be the case.

[QUOTE=03_Impreza_Al;2220394]
Did you buy your car used? Drove it hard? Those R180 rear diffs are pretty tough.

This is the first incident where I've heard about synthetic in the rear diff to cause problems.
[/QUOTE]

I bought it new from Carlsen Subaru (~20 miles on it). I broke it in per recommendations (no high revs, varied speeds on highways for ~1000 miles). I haven't taken it to the track or anything, no donuts, not really any severe launches. I have pushed it several times to near redline on straightaways, have done some "canyon-roading", and tend to drive a bit on the aggressive side. Not sure if that qualifies for abuse...but if THAT is abuse...then well, what's the point of owning the car?? =)

[QUOTE=subie OCD;2220434]Ditto, I frequent the boards often (iclub, nasioc, iwsti) and havent heard any STi owners having drivetrain problems
[/QUOTE]

Right, I did some searches online and couldn't really pull up anything substantial correlating synthetics to broken diffs. But Livermore and Carlsen Subaru seem to be in agreement that synthetics shouldn't be put in the rear diff. *shrug* There seems to be a disparity between the official Subaru word (well, my sample size is only two and one may be biased) and the Subaru enthusiasts/community.



Well anyway, I hope this post helps out some people. Bottom line is, I'm only out $200 and not $2000, thanks to Mike's generous offer. Thanks for the replies.

That Redline synthetic is very popular, hell I used it on my old WRX with no issues and was planning on using it on my STi.


Weird.

[QUOTE=CluskillZ;2221444]
I bought it new from Carlsen Subaru (~20 miles on it). I broke it in per recommendations (no high revs, varied speeds on highways for ~1000 miles). I haven't taken it to the track or anything, no donuts, not really any severe launches. I have pushed it several times to near redline on straightaways, have done some "canyon-roading", and tend to drive a bit on the aggressive side. Not sure if that qualifies for abuse...but if THAT is abuse...then well, what's the point of owning the car?? =)
[/QUOTE]

Sounds good to me. You should try driving a 5spd granny shifting everything :dance:

redline is garbage! i put it in my transmission and it never felt as good as oem fluid did. cant wait until i have the time to get oem fluid and replace it.

I've hard 3 different car serviced by GST on multiple occasion (30k and 60k) using their performance package, and I've NEVER EVER had ANY problems with my cars...

[QUOTE=WRXakaBooSTi;2221662]redline is garbage! i put it in my transmission and it never felt as good as oem fluid did. cant wait until i have the time to get oem fluid and replace it.[/QUOTE]

If you are talking about redline synthetic transmission fluid in the WRX 5-speed, then I would agree with you. The WRX 5-speed snycros dont like the synthetic stuff, however, redline in the rear diff has always been fine (except in the OP's case).

[QUOTE=subie OCD;2221759]If you are talking about redline synthetic transmission fluid in the WRX 5-speed, then I would agree with you. The WRX 5-speed snycros dont like the synthetic stuff, however, redline in the rear diff has always been fine (except in the OP's case).[/QUOTE]

yeah, i should have just stuck with the regular stuff. cant go wrong with oem... cheaper... guaranteed to work

It is true, no syn in our trans or diffs.