I found this thread through searching, but I couldn't reply to it to ask my question:

https://honda-tech.com/zero...79320

I have S4C transmission and on the street it shifts fine. On track, though, I get a grind from 2nd to 3rd after a few laps after the transmission and oil have heated up.

The transmission has new Royal Purple Syncromesh in it, and I'm wondering if I have a mechanical problem or fluid problem.

Has anyone else experienced a similar problem or a problem with RP fluid?

 

I had the same issue with my last transmission (M2B4). I would only get a grind from 2nd to 3rd at above 7500 rpms in certain right-hand sweepers. I ran fresh Honda MTF. I just figured the synchro was possibly starting to go.

 

im having the same problem in my gsr, i run the same tranny fluid, im sure the fluid isnt the cause, ive been wondering the same, it only happened coming out of buttonhook or whatever on buttonwillow, its a 180 degree right

 

You sure its the oil?

EF/CRX chassis doesn't leave a lot of room for the exhaust and puts it right next to the shift linkage. It's not uncommon for the exhaust to move against the linkage during hard cornering. We had a guy at Willow last year who simply could not find 4th gear with he got to turn 8. But ever other time and in every other place it worked fine...

 

That is a possibility I hadn't thought of. I have already trimmed the counterbalance on the shift linkage, but it still makes slight contact with the resonator. That could be exaggerated by an uphill acceleration in second. I've planned on trimming it a little further next time I have the car in the air.

I was, however, getting to the point that I would clutch in and pause to let the revs come down before I tried to engage 3rd, and it would still grind. I think I'll try the Honda MTF, but I'll have to wait a while as the Honda dealership in my town hasn't gotten the reformulated MTF, yet. (Guess they don't sell or service too many manuals)

 

I had this same exact problem, downshifting to 2nd from 3rd mid-Oak Tree at VIR. Redline gear oil solved the problem 100%. Previously I had been using the reformulated Honda MTF (which sucks *****, IMO). Your synchros are probably getting worn, but better fluid might help them last a little longer.

 

Honda MTF is great fluid for the street, but can overheat easily on the track and be useless

I hate Royal Purple with a passion in any case.

Try Redline MTL

 

ditch the crappy non OEM fluid, pull the tranny, lube the input shaft sleeve and clean the splines on the friction material/input shaft.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by B18CXr &raquo;</TD></TR><TR><TD CLASS="quote">ditch the crappy non OEM fluid, pull the tranny, lube the input shaft sleeve and clean the splines on the friction material/input shaft.

</TD></TR></TABLE>

good call- a sticky clutch disc will definitely gives you tons of shifting problems. Use Honda hi-temp uera grease

 

RP website says to use it's engine oil in Honda gearboxes.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by WWDTrackRacer &raquo;</TD></TR><TR><TD CLASS="quote">RP website says to use it's engine oil in Honda gearboxes.</TD></TR></TABLE>
This didn't sound right to me, so I made an application request via Redline's web site. Here's the response:

John,

Thank you for contacting Red Line Oil, in your Acura transaxle in a dedicated road race car I would recommend the MT-90, the shiftability might be a little stiffer at lower temperatures, due to the higher viscosity than the MTL which would be our typical recommendation in the Acura transaxle.
In the Kaaz limited slip for track use in the Acura transaxle I would recommend the MT-90. A clutch type limited slip on the street can require some additional friction modifier to control chatter though in race use chatter wouldn't be an issue plus the friction modifier can impact shiftability making the the fluid becomes too slippery for the synchros.

I have attached the MTL tech report that talks about slippery gear lubes and having the proper coefficient of friction for optimum synchro operation.

Redline

Here's a link to the tech paper they sited: http://www.redlineoil.com/whitePaper/13.pdf

 

i got a similar response a couple years ago.. used MT-90 for a season then that tranny died (can't blame it on the oil though, since it was raced before i got it) .. bought a brand new one and used honda fluid last year .. changed the oil every 2-3 races .. put in a stock shifter lever and extended the shift **** about a foot .. stiffening the motor mounts also helps

Thank you for contacting Red Line Oil, in your Integra transaxle I would recommend the MT-90 strictly for road racing. I wouldn't recommend using the 75W90 or adding any friction modifier to the MT-90 as it will reduce the friction and the performance of the synchros. You might experience some chatter when making a slow/tight turn in the pits, the shiftability on the track being the more important issue.

 

Hmm...that's especially interesting, as I'm using the 75W90.

 

OEM MTF sucks the big one for race cars.

KAAZ is all my transmission gets

 

Thanks for the responses, guys. I also contacted Redline by phone, and Greg also recommended MT-90. Looks like that is the direction I'll be going.

 

where are you ordering from, i wouldnt mind testing it out too. i was interested in trying the motul though

 

I'll be getting it from a local race shop.

 

Slammed, I assume you have a clutch type LSD?

Not quite sure what the OP has for a tranny, S4C.

Anyhow, on my stock ITR tranny, I used Motul 300 and ran with Redline at Streets. On my third session, the car started to develop a high RPM grind on third gear at the middle of the straight on the back end. That REALLY pissed me off because I NEVER had that problem when I was running the new Honda MTF. Dropping from third to second gear was not smooth at all as well.

I switched back to Honda MTF and all is well again.

I was going to try Redline MT90 but I've been scared to try something new since the tranny has been working great since I put in the Honda MTF although I haven't been to an HPDE to test out the tranny. I've only done a few high RPM runs with the new fluid.

Any suggestions? Stinky, what Redline gear oil are you referring to?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by snowboardgeek1 &raquo;</TD></TR><TR><TD CLASS="quote">Slammed, I assume you have a clutch type LSD?

Not quite sure what the OP has for a tranny, S4C.

Anyhow, on my stock ITR tranny, I used Motul 300 and ran with Redline at Streets. On my third session, the car started to develop a high RPM grind on third gear at the middle of the straight on the back end. That REALLY pissed me off because I NEVER had that problem when I was running the new Honda MTF. Dropping from third to second gear was not smooth at all as well.

I switched back to Honda MTF and all is well again.

I was going to try Redline MT90 but I've been scared to try something new since the tranny has been working great since I put in the Honda MTF although I haven't been to an HPDE to test out the tranny. I've only done a few high RPM runs with the new fluid.

Any suggestions? Stinky, what Redline gear oil are you referring to?</TD></TR></TABLE>Weird, I was finding a 3gear wall in my K tranny using the new honda MTF on the same location as you, coming out of the bowl at SOW CW. i was gonna try something new, redline maybe, but now your experience got me thinking twice about whath to run now.

 

RP synchromax is the absolute worst fluid I've ever tried, I'll be going back to oem fluid soon.

 

Interesting. We ran CCW that day I developed the grind. I'm hoping that the grind is based on the fluid I was using at the time. If not, then its time for a new tranny.

 

two things happene when racing
1, you shift faster
2, your gearbox oil temp is higher

we have found we can delay the onset of syncro failure when racing by using the motul ff oil , which is also excellent with plate type diffs

the real solution is a gearbox oil cooler

much of the heat in the gearbox appears to be transmitted from the engine

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by BigAl &raquo;</TD></TR><TR><TD CLASS="quote">two things happene when racing
1, you shift faster
2, your gearbox oil temp is higher

we have found we can delay the onset of syncro failure when racing by using the motul ff oil , which is also excellent with plate type diffs

the real solution is a gearbox oil cooler

much of the heat in the gearbox appears to be transmitted from the engine </TD></TR></TABLE>
About the 2 things, I concur...for one of them. Apparantly the tranny oil temp gets higher, and I've been told the Honda MTF, even the newer version, is too thin, so it gets worse when it gets hotter on the track.

However, I do not shift any faster or harder...I'm nice to my tranny! And I only experience the 3rd gear wall when I'm a few laps into it...guess I gotta try something else. Redline MT90 is what I had in mind next, but IIRC some mention having problems w/ MT90 in this thread.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by snowboardgeek1 &raquo;</TD></TR><TR><TD CLASS="quote">Stinky, what Redline gear oil are you referring to?</TD></TR></TABLE>

I'm using Redline 75W90 gear oil, only stuff I could find at the time (meaning: I didn't call Redline and ask for their suggestion). I've had it in there for 3-4 events without any issues, so I'm happy with it. The fact that THEY say not to use it worries me a little though.

 

Anybody here ever use Amsoil in their tranny for a track outing? I've heard at least one positive review for it.