Grinding gears
#1
Registered User
Thread Starter
Grinding gears
Been grinding gears lately.
mostly at the track, both Road Atlanta and Daytona. 4th and 5th mostly.
changed trans fluid last year, Royal purple 75-90. It’s what I had on hand. That fixed the 3rd gear grind I was having when I first got the car.
clutch system is all new, from the master cylinder all the way to the disc. Bled before Daytona and RA with ATE super 200.
should I swap the fluid for Honda fluid?
or set my clutch piston to ensure full disengagement?
seems fine driving around town. Only time I have issues is when I’m shifting/reving hard on track.
mostly at the track, both Road Atlanta and Daytona. 4th and 5th mostly.
changed trans fluid last year, Royal purple 75-90. It’s what I had on hand. That fixed the 3rd gear grind I was having when I first got the car.
clutch system is all new, from the master cylinder all the way to the disc. Bled before Daytona and RA with ATE super 200.
should I swap the fluid for Honda fluid?
or set my clutch piston to ensure full disengagement?
seems fine driving around town. Only time I have issues is when I’m shifting/reving hard on track.
#2
Been grinding gears lately.
mostly at the track, both Road Atlanta and Daytona. 4th and 5th mostly.
changed trans fluid last year, Royal purple 75-90. It’s what I had on hand. That fixed the 3rd gear grind I was having when I first got the car.
clutch system is all new, from the master cylinder all the way to the disc. Bled before Daytona and RA with ATE super 200.
should I swap the fluid for Honda fluid?
or set my clutch piston to ensure full disengagement?
seems fine driving around town. Only time I have issues is when I’m shifting/reving hard on track.
mostly at the track, both Road Atlanta and Daytona. 4th and 5th mostly.
changed trans fluid last year, Royal purple 75-90. It’s what I had on hand. That fixed the 3rd gear grind I was having when I first got the car.
clutch system is all new, from the master cylinder all the way to the disc. Bled before Daytona and RA with ATE super 200.
should I swap the fluid for Honda fluid?
or set my clutch piston to ensure full disengagement?
seems fine driving around town. Only time I have issues is when I’m shifting/reving hard on track.
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Chuck S (07-09-2024)
#3
Registered User
Definitely check the clutch pedal free-play, if you didn't do that when the new master was installed.
#5
Registered User
Thread Starter
#6
Correct freeplay is 1/4", and all of it is inside mc. There should be zero play between rod and back of piston it presses against.
#7
Join Date: Nov 2007
Location: Illnoise. WAY downtown, jerky.
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The only correct freeplay setting is 6mm (1/4").
More than that will move you toward grinding from incomplete disengagement.
Less than that will move you toward a slipping clutch from incomplete engagement.
75W90 is just the weight of the fluid. Its a little thick...but the fluid weight itself shouldn't cause a grind (within reasonable allowances).
However, if you are using 75W90 GL5 hypoid gear oil not meant for synchro's...that's bad, and will absolutely cause issues. Typically GL5 hypoid gear fluids are too slippery for synchros, and a lot will also damage brass synchros due to their EP additives for hypoid gear use.
You need a GL4 manual transmission fluid, or a GL5 specificially designed for use with synchronizers.
Honda MTF is the best overall fluid for street use. For track use, its also fine if you are OK with frequent fluid changes. The current Honda MTF (MTF2) is about a 70W75ish or 75W80ish fluid. Its a little on the thin side if you're banging the car out at a track for 15-20+ min sessions.
Or....Royal Purple Synchromax, Redline MTL, Amsoil MTF...all examples of usable aftermarket transmission fluids that should last longer and provide more high temp protection for track use, as compared to Honda MTF2. All of them are thicker than MTF2. But they're designed for synchronizers.
Last edited by B serious; 07-08-2024 at 11:14 AM.
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Dibsen (07-09-2024)
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#8
Registered User
Thread Starter
This was what I had on hand. 3rd gear was grinding when I bought the car so I wanted to change asap. This fixed the grind immediately.
Says it’s also good for trans, GL4 or 5
im going to adjust the free play, it’s certainly more that 1/4inch. Maybe 1”. That ought to fix it. If not, then I’ll try swapping to Honda MTF.
thanks for the feedback
#9
RTFM It's not good for the gearbox. The car needs Manual Transmission Fluid (MTF) and there are many acceptable products including Honda's own MTF, Royal Purple, etc. Threads abound.
Acceptable, temporary substitute for MTF is 10W-30 motor oil, not GL5 gear oil.
Royal Purple makes lots of lubricants. If you want Royal Purple MTF use this not hypoid gear oil (differential oil).
Currently in my gear box although I can't detect any difference from Honda MTF. Seems ANY MTF makes the box shift smoother immediately after the oil change.
Additives and viscosity matters. List of MTFs.
-- Chuck
Acceptable, temporary substitute for MTF is 10W-30 motor oil, not GL5 gear oil.
If Honda MTF is not available, you
may use an SAE 10W-30 or 10W-40
viscosity motor oil with the API
Certification seal that says ‘‘FOR
GASOLINE ENGINES’’ as a
temporary replacement. However,
motor oil does not contain the proper
additives, and continued use can
cause stiffer shifting. Replace as
soon as it is convenient.
may use an SAE 10W-30 or 10W-40
viscosity motor oil with the API
Certification seal that says ‘‘FOR
GASOLINE ENGINES’’ as a
temporary replacement. However,
motor oil does not contain the proper
additives, and continued use can
cause stiffer shifting. Replace as
soon as it is convenient.
Currently in my gear box although I can't detect any difference from Honda MTF. Seems ANY MTF makes the box shift smoother immediately after the oil change.
Additives and viscosity matters. List of MTFs.
-- Chuck
Last edited by Chuck S; 07-09-2024 at 06:32 AM. Reason: Added link to MTFs
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Save the Manual Wagons! (07-09-2024)
#10
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This was what I had on hand. 3rd gear was grinding when I bought the car so I wanted to change asap. This fixed the grind immediately.
Says it’s also good for trans, GL4 or 5
im going to adjust the free play, it’s certainly more that 1/4inch. Maybe 1”. That ought to fix it. If not, then I’ll try swapping to Honda MTF.
thanks for the feedback
Says it’s also good for trans, GL4 or 5
im going to adjust the free play, it’s certainly more that 1/4inch. Maybe 1”. That ought to fix it. If not, then I’ll try swapping to Honda MTF.
thanks for the feedback
The fluid you're using is non corrosive to synchros, but probably doesn't have the friction modifiers that a synchromesh fluid has. Royal Purple Synchromax is what you want, if you'd like to stick with RP.
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Save the Manual Wagons! (07-09-2024)