We've been experiencing what I think is abnormally high synchro wear. This is one of two transmissions where I've seen a lot of wear on the 3rd and/or 4th gear synchros. On this particular transmission, we had probably 20 passes on the original set of OEM Honda synchros, 20 passes or so with a new set of OEM Honda synchros, and then around 20 more passes with a new set of GearSpeed carbon synchros.

Each time, the clearances came out below service limit even though they clearance at .030"+ when installed. With the limited number of passes we've had on the trans, I think there's either something wrong or nobody talks about the level of maintenance needed on the synchros.

Motor is your typical SFWD trim motor with a GT4294R, run mostly at 26psi last year with a handful of passes at 32psi. The car trapped just a little over 140 to 145mph with an ET of 10.5-ish. Driver is a granny shifter. Redline/shift point is 10,250.

The mainshaft clearance was set within spec. I don't remember what it was, but I can re-measure if needed.

The questions are:
Should we be seeing this much wear? Is it normal?

PICTURES:

4th Gear - key highlight here is the wear on the synchro cone. The striations are from the pads on the carbon synchro ring. The striations are grooves worn into the synchro cone.


Same 4th gear, different angle.


Clearance was .006" on 4th gear and .0014" on 3rd gear; clearances both started at .030"+ (serv. limit is .020"). The springs are a little worn, but nothing major.
Synchro rings/springs were new when installed. Gears were used slightly and wear on the gears were fine the last time the transmission was overhauled (20 to 25 passes ago).


Picture of the 4th gear synchro ring. Third gear synchro looks pretty much the same. I'll try to put up a picture of a new ring for comparison.

 

That sycnrho is beat. Is the gear cone grooved or can it be cleaned up? If its grooved at all its done.

On tramissions I build specifically for drag I set the mainshaft clearance versus checking to make sure its within the OEM tolerance.

Synchro trannys for drag with high power do require a lot more maintanence than a dual purpose trans (whether its drag or track), though I've not seen wear that bad in person.

What fluid was used in the trans? Temps logged? If so what were they? What clutch and how much clamping force does the pressure plate have? Flow control?

 

The actual dog teeth themselves can be cleaned up, so that is not really an issue here. What is the issue is the "quick" wear on the synchro ring which, tbh, is not really abnormal so to speak.

It doesn't really matter if you granny shift or not (unless you are really talking about keeping your foot on the clutch for like a second, which I doubt), you are still shifting at a high rpm (10k rpm?) with high power (600-700+?), so the synchro rings still have their work cut out for them.

Coupled with the harder material the gears are made from (compared to oem), of course the rings will wear quicker compared to with an oem gearset, regardless of how much power you are making or what rpm you are shifting at. This is why we always recommend those who are using our gears to check for wear/tear on a regular basis so as to keep them in the best condition.

This "high maintenance" is something we are aware of, and we are working on some stronger/more durable synchro rings to be used specifically with the synchro gear sets. Beyond that though, there really isn't much else to do aside from using a weaker material for the gears which will help increase synchro ring life but at the expense of the gear teeth being not as strong/durable. We designed these gears to withstand 900whp+ because 90% of our customers are running more than this. Maintenance is an unfortunate necessity

As Aquafina also asked above, what fluid are you using, and did you log your tranny temps?

Any questions, please feel free to PM/Email me

 

Wow. I've never seen the pads on the ring look like that.

I'm also curious as to what fluid the trans sees. Not to familiar with temps in the trans, but if anyone can say what they typically see, please speak. lol

 

Thanks for the input all.

No logs on the tranny temps, but we're not hot lapping it either.

Clutch: Tilton twin cerametallic with flow control. I don't know what orifice size we're using right now tho.

We're using Honda MTF-II.

The fluid was like glitter. And, there were chunks of the braking material littered sparsely here and there.

The grooving is deep enough to catch a nail. The gears are probably usable with a set of OEM Honda synchros, but not with a set of carbon synchros because of the wear pattern.

 

Thats part of the issue.

 

That's really the only thing we can do for a synchronized tranny at this point because we're definitely not turning the power down.

 

1) Low/Moderate Power. Street Use
Requirements - Low Viscosity Transmission Fluid
Choices - Honda MTF, GM Synchromesh, Torco MTF

2) Low/Moderate Power. Street, Road/Race
Requirements - Low Viscosity Transmission Fluid, Limited Shock/Wear Protection & Stability, Meet GL4 Requirements
Choices - GM Synchromesh (Not Rated), Torco MTF

3) High Power, High RPM, Race Use
Requirements - Low Viscosity Transmission Fluid, Advanced Shock/Wear Protection & Stability, Meet GL5 Requirements
Choices - Torco RTF (is actually rated to GL6)

You are using a Level 1 fluid on a Level 3 tranny

There are other fluids available (except for Level 3. There is nothing else available), but the ones above are the ones I recommend.

 

sorry to thread jack but, the GM Synchromesh is the same as the Pennzoil Synchromesh right?

and how does the royal purple stack up against GM, and Pennzoil's synchromesh? it's easier to get a hold of from where i'm from.. i do monthly autox's and i have a jdm gsr trans with oem lsd i'll be putting in

 

Supposedly it is, and at half the cost

I've no experience with the Royal Purple, or what it consists of. Maybe Mista Bone could answer this one?

 

RP Synchromesh is 1/2 their motor oil and 1/2 Pennzoil Synchromesh.

Pennzoil SM is 5w30 oil, semi-synthetic.

I have customers about to test straight 30w motor oil on road racing trannys, myself I'd like to play with the Torco if I had a DD 5 speed.

From what I've dealt with, Redline Shockproof tranny fluid or Torco's fluid.

Myself I won't even run the pisswater Honda MTF-II in a OEM tranny!

 

so Pennzoil synchromesh > RoyalPurple SM... right? being a 5w30 semi-synthetic it'll be fine on my jdm gsr + oem lsd for occasional road racing? correct?

 

I must concur with Bone...

I run Redline lightweight shockproof with GREAT results (Straightcut Saenz set) ... SHifts llike butter... Making almost 700 whp.... OEM syncros too.... NO ISSUES... AT all.


Its a real pain in the *** to clean up though... LOL

 

I have three customer cars (Civic/CRX) running SCCA ITA using Pennzoil Synchromesh without issues.

 

i run Amsoil synchromesh i get for about $8 a bottle, no problems here but i'm not at high power or anything

just thought i'd throw another fluid in for consideration

 

Just curious...do drag guys even get the trans fluid up to temp..ever? This question is in regards to a single-purpose car.

 

Bottom line is that in that car with that gearset (ESPECIALLY IF ITS A PURPOSE BUILT DRAG CAR)... Straight Honda MTF is a no no. after initially going through (checkup/maintainance) my straightcut box, ill go drive the car for a minute with some cheap 10/30 in it, but then almost immediately dump it and switch to thew Redline lightweight shopckproof bearsnot.

You can HEAR the box get quieter. Immiediately after the switch, you dont have to be a genius to figure the rest out. Mine is an OEM synced set as well, shifts like BUTTER, even when cold using the redline stuff, and I havent seen any detrimental effects from its use regarding the bearings. I put ALOT of pulls on it and usually dont pull it apart untill I hear/feel something wrong

It plays nicely with the suncros and I have never seen an issue where any of the cones on the gears have looked like that... Ive broken teeth off from power, but never worn a gear or a syncro like that

 

Ever seen gear oil detonate?

Thicker oil is less likely to have it happen.

 

I asked a simple question. Nothing in your response is related to it.

Do drag cars get their trans fluid (and this probably applies to engine oil too) up to temp? Regardless of what you use, if you're making runs on cold fluid, I can imagine why anyone would have problems. I doubt a 1/4 mile run is going to get it operating temp, and even then the first run will be on completely cold fluid.

 

And???? I was making a statyement... SO what.. Seems maybe you should read into what I wrote... There IS indeed relative info in it. DIRECTLY mentioning temp. COld shifting specifically, and 0 issues with using lightwieght shockproof fluid...

HOWEVER I didnt mean to qoute you (even though your above accusation is incorrect.


KTHx