Grinding synchros...

Richard · Post by **Richard** » Tue Oct 18, 2005 5:18 am

I've gotten into the habit of "double bumping" the throttle between gears when downshifting. I've got a good idea of what RPM's to bump to at certain speeds. I push the clutch, pull it out of gear, do the first bump to match the syncros, then I shift, then bump to match the RPM's, then release clutch. Usually its pretty smooth and relatively quick. Sometimes I overshoot the RPM's and get a little clutch grab when I let it out. My tranny only gives a crunch upshifting when I'm really on it and shift too fast.

Is this a bad thing to do? I ask because I learned stick on a Festiva that I beat the living dog shit out of. I'd pretty much pushed in the clutch, shifted, and let go of the clutch. No bumping, no matching, no care (or idea) of what I was doing to the drivetrain. Hey I was learning. And it was a Festiva. Did the same thing on my motorcycle. I figured I was doing something wrong when the tire locked up and the clutch started slipping later in it's life. I don't dare to downshift in the Foxbox. It too is a pile, like the Festiva, but I need it to be a reliable pile/winter car.

Any thoughts? I'd like to keep the trannies in the cars I own from now on. I have to admit I haven't smelled burning clutch since getting the scoob and using the "double bump" method.

vrg3 · Post by **vrg3** » Tue Oct 18, 2005 5:25 am

If I'm reading that correctly, it doesn't sound like you're doing anything for the synchros at all... You may want to read up on double-clutching, which is what (I think) you want to do.

entirelyturbo · Post by **entirelyturbo** » Tue Oct 18, 2005 6:46 am

Double-clutching is great on your transmission, but there really is no such thing as a free lunch.

I sincerely believe that my clutch release system came apart due to my previous double-clutching habits. Everytime you move the clutch pedal, you put some stress on the clips that are holding the throwout bearing to the clutch fork. By double-clutching, you're causing these stressful moments to happen about 3 times as often, and with more stress since you're doing it rather quickly. I had gotten my clutch replaced at 110k miles, and not long after that, I had begun to tinker on my car myself, which included adding Valvoline partial synthetic oil to my gearbox. It definitely didn't like that, and it would grind everytime I shifted into 4th. So I had to learn the art of double-clutching in order to engage 4th, until I later learned that I should stick to dino. By then I had learned to enjoy double-clutching, and appreciated its reduced wear on the transmission. Not 17k miles after I had just gotten the clutch, my throwout bearing came loose and was rattling very loudly whenever I pushed the clutch pedal in. I bravely did my first tranny drop and replaced the whole shebang in there, throwout bearing, fork, clips, etc., and stopped my double-clutching right there. I've gone another 20k since then with no problems.

If you have a SS, then you have a hydro clutch, whose release system is better-suited to something like double-clutching. But I'm stuck with a cable clutch, and I've learned to adjust my driving habits accordingly.

Thanks for the info though Vikash. So do you think it would be in the transmission's (in its entirety, from the front diff to the synchros) best interest to run a 50/50 mix of GL4 MT-90 and GL5 75W90NS like I was before? Would that balance out the sulfur additives content enough to keep everything happy?

vrg3 · Post by **vrg3** » Tue Oct 18, 2005 1:41 pm

subyluvr2212 wrote:Double-clutching is great on your transmission, but there really is no such thing as a free lunch.

Yeah, you have to balance things... Keep in mind though that it's a lot easier to replace clutch release components than synchronizers.

Also, many of us are likely to wear out the clutch friction material before the release system, even in the face of double-clutching.

So do you think it would be in the transmission's (in its entirety, from the front diff to the synchros) best interest to run a 50/50 mix of GL4 MT-90 and GL5 75W90NS like I was before? Would that balance out the sulfur additives content enough to keep everything happy?

I am wholly unqualified to answer that question. I have no idea how much EP protection is really necessary, how much safety cushion the GL-5 spec provides, how much EP protection GL-4 provides relative to GL-5, or how much that quantity of EP additive would affect the synchros.

Phil did find his shift quality improved dramatically when he replaced whatever his car had with Redline 75W90NS. My car shifts with Redline MT-90 shifts smoother than his though (not counting all the sloppiness in the linkage).

But Subaru transmissions seem to have a lot of individual personality.It's possible that the two oils are more or less equivalent with respect to synchro effectiveness... Like, maybe Redline did use yellow-metal-inert sulfur compounds for EP protection.

If I had had sufficient funds, I probably would have first tried running 75W90NS, and then switched to 50% MT-90 if shift quality still sucked, and then straight MT-90 if it still sucked.

I do think my front differential's a teeny bit louder than it used to be, but I may be just imagining it.

snowboarded · Post by **snowboarded** » Fri Nov 11, 2005 7:16 pm

I just swapped in the redline 75w 90NS and I notice worlds of difference. My 2nd and 3rd synchros will still grind if I am slamming it into gear at high RPMs but if I am driving spiritedly, there's no noise aside from the occasional gear engage sound. Also redline smells horrible, worse than other tranny fluids, fresh. I hate to have to smell it after its all burnt and old. Any reason for this or am I just imagining the smell being really bad?

legacy92ej22t · Post by **legacy92ej22t** » Sat Nov 12, 2005 4:59 am

No, gear oil is the worst!

AWD_addict · Post by **AWD_addict** » Sat Nov 12, 2005 5:50 am

My front diff oil smells like burned mashed potatoes and meatloaf. The rear diff smelled like rotten death until I changed it to match the front.
Gear oil is definetly the worst smell I've found on the car.

Post by **Legacy777** » Sat Nov 12, 2005 7:44 am

I freaking hate my tranny. 2nd gear grinds once things warms up. I don't know what the hell the deal is. I'm probably going to add some synchromesh and see if that helps at all.

Post by **Legacy777** » Mon Nov 21, 2005 5:02 am

Since I've tried several different fluids and still get grinding from first to second, I decided to try the tranny cocktail posted by uncle scotty on nasioc. I sucked out about 2qts of fluid on friday, and added a qt of redline light weight shock proof & a qt of syncromesh.

So far, seems pretty good, and hasn't ground between 1st & 2nd, however I need to drive more. It doesn't really feel any better......it just doesn't grind.

93forestpearl · Post by **93forestpearl** » Mon Nov 21, 2005 6:41 am

I happen to like mashed potatoes and meatloaf, but not the burned variety.

I don't know what to think of the 75w90ns. I had my tranny rebuilt four years ago and now it grinds again on the 1-2. I ran the Redline the whole time. It probably has more to do with driving in and out of driveways 80 hours week for two summers which totaled 50k.

On my next tranny I think I'll try the shockproof.

Post by **Legacy777** » Mon Nov 21, 2005 3:21 pm

Why not try it on the current one?

High PSI · Post by **High PSI** » Mon Dec 05, 2005 6:48 pm

Josh,

What exactly was that cocktail besides the synchromesh and the shock proof (haven't stumbled across his recommendation yet on NASIOC)? How's it working out after a couple of weeks of driving with it?

Post by **Legacy777** » Mon Dec 05, 2005 7:15 pm

1 qt synchromesh
1 qt lwsp
2 qts 80w-90 Castrol.

However I just used the swepco that was already in there.

Seems to have helped the grinding. The tranny isn't really any more smooth in shifting, but I haven't ground 2nd gear any more....so that's good to me.

Adam West · Post by **Adam West** » Tue Jun 13, 2006 5:36 am

He's the thread on Nabisco. Thanks Josh, I found it in like two seconds...

http://forums.nasioc.com/forums/showthr ... 2+cocktail

Here's some interesting bits of how-to I extracted from the thread...

Uncle Scotty's Cocktail for Subi Tranis:

1qt Redline lightweight shockproof
1qt Pennzoil Synchromesh
2qt Castrol HypoyC 80w-90

Uncle Scotty says...

" ...juust do it....and remember.....do NOT dump 4 qt in the tranny!!!!!!!!

That WILL overfill it---bad juju.

Add ~3.3 - 3.4...drive the car---check....repeat a couple times....make SURE it isn't too much before ya add more.

Add the lube SLOWLY into the dipstick tube or you WILL get more UNDER the car than IN the tranny

...and the rear diff can use GL-5 whatever.....I'd use a syn like M1

Example Costs:

LW Shockproof: 8.99
Castrol 80w90: 4.29 x 2
Penzoil Syncromesh: 6.09
RL 75w90 for the diff: 8.99

Grand total: 35.13 w/ tax

Do we use Red Line SuperLight ShockProof or just the LightWeight ShockProof? Lightweight

From what I gathered ...

Here is the Official Cocktail Pouring Order

1. 1qt. Lightweight Shockproof

2. 1qt. Pennzoil Schromesh

3. Finish with the remaining Castrol Hypoy C but only fill to the Full line on the dipstick. Do not dump in both remaining quarts. I believe total volume for the tranny is 3.4 - 3.6.

Adam West · Post by **Adam West** » Tue Jun 13, 2006 5:38 am

My question is this...Since these instructions are for a mainly WRX (tranny) audience... Does our tranny hold or more or less than the amount described?

snowboarded · Post by **snowboarded** » Tue Jun 13, 2006 1:39 pm

I put about 3.4 litres of redline in mine. And the level was good.

Post by **Legacy777** » Tue Jun 13, 2006 6:50 pm

Adam West wrote:My question is this...Since these instructions are for a mainly WRX (tranny) audience... Does our tranny hold or more or less than the amount described?

It's the same.

niksus · Post by **niksus** » Sun Jul 09, 2006 9:15 am

Hi, i have a 1989 wagon 0n 379,000kms. i had a sticky 2nd gear and a whining noise in the box. i flushed the oil out and with the right oil i added 25% MOREYS OIL STABILISER at a cost of $18 NZ. after 2 days it fixed the sticking gear change and reduced the whining by 80%.
i hope this helps. i live in NZ.[color=red][/color]

snowboarded · Post by **snowboarded** » Wed Aug 30, 2006 8:15 pm

So I finally put in the STi Group N tranny mount and wow!!! That is amazing. Shifting feels light years better, and I only grind if I am going in gear with a heavy right foot. +eleventy million for this mount!

John Drivesabox · Post by **John Drivesabox** » Sat Sep 23, 2006 11:00 pm

Got 2 orders of the cocktail from Amazon.com. They even have it all grouped together, add one to your cart and they automatically recommend everything else (very convenient).

I'll be adding serving 1 to my '91 SS tomorrow, giving the tranny 2 days to fully drain. Serving 2 will go in wifey's '93 SS once it comes back from paint. More to come.....

John Drivesabox · Post by **John Drivesabox** » Tue Sep 26, 2006 11:37 pm

Put the cocktaill in my '91, wasn't impressed at first but now after a few days...

Used to give me a slight grind going into second and third unless I was real cautious. NOW that is almost completely gone, I can shift through the first four one as easy as the next. Gear matching with a super heavy duty clutch is never easy without double clutching (or bumping, which is not something I'm a huge fan of anyways), but I can shift with relative ease, my heavy clutch is the only real obstacle in fast shifting now.

5th on the other hand is a different story, used to always give me a headache going in there, a real uncomfortable grind, but never hesitates to suck the shifter into gear regardless. That has not been alleviated, I can still ease it in or double clutch or a number of things but it's definitely not like 1st-4th.

Overall, it was worth the $50 shipped I paid per cocktail, can't wait to see what it does for wifey's '93 SS.

Where can I get one of those Group N tranny mounts? Location, link, price, that'd be sweet.

free5ty1e · Post by **free5ty1e** » Wed Sep 27, 2006 2:40 am

Word. Uncle Scotty's cocktail is the shizznittle-doo.

entirelyturbo · Post by **entirelyturbo** » Thu Oct 19, 2006 6:48 am

Okay. Review time.

While I was playing mechanic this past weekend, I changed the regular dino gear oil in my trans for GM Synchromesh. Get this: my dealership actually carries it. We frequently use it in Subarus. I actually figured if it's recommended by my own dealership, then I should at least give it a shot.

I wasn't grinding gears on the dino oil, but I would take a little time for 4th gear, for example, to engage if I was downshifting from say 70mph. 3rd gear was a little bad too. Again, not grinding, just a little resistant.

After a spirited drive this evening, I will report that I noticed a BIG difference.

That resistance is pretty much gone. I can downshift into 4th no problem, without any really significant holdup. 3rd felt just as good. I could even downshift into 3rd at about 60, and it still went in perfectly smoothly.

Of course, I'm gonna hold off before coming to any stunning revelations. After all, my trans didn't start grinding on the Valvoline partial synth gear oil until a few months later.

But so far, I'm impressed.

entirelyturbo · Post by **entirelyturbo** » Wed Feb 07, 2007 5:29 am

Review time again.

A couple weeks ago, I changed out the GM Synchromesh for Motul Gear 300 75W90, for two related reasons:

1) I wasn't comfortable running full GL4 oil in my tranny
2) This is actually kinda confidential information, but Subaru is NO LONGER allowing dealers to use GM Synchromesh to alleviate grinding

That said, I've driven nearly 1500 miles on the Motul oil, and am very happy with it. I even think it's an improvement over the Synchromesh. I've never found it this easy to shift into 2nd, even when I'm driving hard. Plus I have the peace of mind of using the correct GL5 oil.

So, Motul gear oil = thumbs up. Give this stuff a try next time you change your gear oil, and DO NOT use the GM Synchromesh.

Post by **Legacy777** » Fri Feb 09, 2007 7:18 pm

That's good to hear.....Michael, did you run uncle scotty's mix at all?

How did it compare to that?

I have an intermittant leak on the one axle o-ring seal.....so I may have to replace the fluid. If I do, I may try the motul.

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Grinding synchros...