Shifting Into 5th gear grinds at high rpms

[tadaima]

I noticed that when shifting into 5th gear at high rpms abover 5K (redline at 7K), that it grinds a little.

Is something wrong? Change tranny oil? Sycros.

Just 5th though.

Thanks

 

[StiMan]

i can't tell u what wrong, but for about 3 of my mates and including myself who have had crunching from changin gears, have all been "remidied" by putting in Redline Lightweight Gear Oil.

cheers

 

[tadaima]

Yea Heard that works well for a lot of people, but with a Honda tranny "93 del sol", they take 10w30/10w40 oil. Maybe I should go synth 10w40?

 

[StiMan]

sorry

i have no idea what viscocity oil the redline lightweight oil is,

all i know is that it worked for me and about 3 other wrx's who complained of this problem

 

[Ma-fia]

My knowledge of how transmission works is fairly limited, but I have been reading a lot and this is what I can add to the topic.
Transmissions with automatic syncros's let the syncro's to match engine speed and geer speed.
Say, you're shifting from 4th at 5K rpm to 5th and rpms drop down to 3K rpm. If you simply jam it in the geer, you do not give the syncro time to match the speed, therefore higher syncro wear and later on grinding. It might be an indicator of a syncro not doing the job 100% right; if this keeps happening you might end up damaging the syncro and then the 5th geer over enough time; 5th is the smallest in the tranny and is most vulnerable if you push it.
I've heard a lot of good things about Redline, too. If you use Redline and "baby" your transmission a bit, you might be able to forget about the problem forever.
If you would like more details, I can post the whole "spiel" on why's and what's. This information has helped me to understand quite a few things.

 

[90hardbody]

Redline's MTL or MT-90 would match your viscosity requirements. They state clearly on the label which oils they can replace (5w30, 10w30 for MTL or 10w40 for MT-90).

I put MT-90 in my Nissan, and besides the instant improvement, the shifting continues to get better and better (about 2 months so far).

 

[tadaima]

ma-fia/Hardbody:

Thanks for reminding me about the syncro stuff...think I heard that on some other forums back that. True, it also maybe due to my crappy shifting, I usually dont add much or any gas when shifting to the next gear, maybe next time I should tap the throttle to keep the rpms near what I am shifting at.

I normally drive motorcycles and with a wet clutch I guess I dont have to worry about this, and I shift pretty fast with the clutch being in a hand instead of a foot.

I always learn to let go of the throttle quickly before shifting on a motorcycle or I end up bouncing off redline accidentaly.

...I'll also try redline see if that helps..

 

[MarkC]

I put Amsoil 75W90 in my Cherokee's 5-speed tranny, and it shifts perfectly.

 

[Kestas]

I was once a student engineer at Ford Manual Transmission Design for a summer. After learning how a manual transmission works, I developed a technique for shifting where I only put moderate force on the shift stick while engaging a gear. This allows the synchronizer to come up to speed and do its job of matching component speeds. It barely takes a moment for it to happen. It's the drivers who try to slam it into gear pretending that they're race drivers that have high repair bills.

 

[tadaima]

kestas: Well I guess that's the lesson learned by roughing anything up in the car. Figure with an AT tranny, stepping on the gas hard and trying to redline with it doesnt make the tranny any more reliable.

Yea the MT doesnt have any problems when I just drive normally, but I would think that the tranny should at least have the capabilities of allowing me to shift at higher rpms from 4 -> 5 without griding. The car has about 127K, so I guess who knows what the last owner did with it.

 

[mrchecker]

Some clutches have some sort of centrifugal assist mechanism, usually weights on the release fingers. If the clutch is near the end of its life (I assume this is a hydraulic or self adjusting cable clutch), pedal pressure is not enough to overcome the weights at high RPM. Just a thought in case different trans fluid doesn't cure it.

 

[Bob Woods]

Change the tranny lube, I have fixed a lot of tranny shift compliants by just putting in the OEM recommended oil.

 

[Ma-fia]

quote:

---

Originally posted by Kestas:
I was once a student engineer at Ford Manual Transmission Design for a summer. After learning how a manual transmission works, I developed a technique for shifting where I only put moderate force on the shift stick while engaging a gear.

---

This is exactly what I was referring to.
I am trying real hard to follow this, and most of the time it works, I can feel it going in with no force. I've learned about this technique about a month ago and I noticed a slight improvement in my shifting. What I do not understand yet -- is the 1st gear. There is a sharp turn, and road goes steep uphill (onto the bridge), so I can't keep bogging the car in the 2nd, and rev-matching doesn't really help to squeeze it in the 1st, tranny doesn't have any problems, but there's no feeling of it "sliding" into the gear. Usually I try to stop, but when I have someone on my rail, I can't wait for a whole minute for the gears to "calm down".
(BTW, it's an 02 Ford Focus).
I also think I need to drain the junk the car came with, and switch to OEM synthetic fluid, it would probably help.

 

[Gary Allan]

Did I miss something ..or has the vehicle NOT been mentioned here

Some vehicles develop this problem ....the V-tech Hondas for one. This IS a vehicle that many choose to shift into OD @5000+ rpm (visions of people reliving "Fast and Furious")

No one here has explored the characteristics of the trans.

If this was a 2.9 V6 Ford cracking heads ...would we be asking what coolant was used???? (for those who don't know ..2.9 Ford V6 heads cracked quite frequently - hence the short life of the engine until it evolved into the 4.0)

Sorry - my bad!!!! I finally saw ONE mention that this is a Honda trans (now note my F&F referrence above).

[ January 25, 2004, 01:56 PM: Message edited by: Gary Allan ]

 

[Whimsey]

Ma-fia,
If you're tranny requires a Mercon ATF then you might want to give Schaeffer's #204S Dexron III Supreme a shot. I used it in my Ford truck tranny which had Mercon from the factory and shifted poorly, like your's. Wow the difference is night and day. I have a 1996 Contour with the MTX-75 manual tranny and it also required Mercon. The shifting quality was also very poor. Ford came out with a special and $$$ synthetic fluid just for this tranny. It works really good but next time I'm going to use the Schaeffer's #204 in there also. People that went with synthetic such as Mobil 1 had problems and had to add a friction modifier. I think a true total synthetic ATF might be too slippery for the syncro's without using the Ford friction modifier. Don't have that problem with Schaeffer's # 204 with is a semi-synthetic.

Whimsey

 

[Kestas]

I've never tried rev-matching. I heard it's a technique where, when properly executed, you can shift gears without using the clutch.

There are some occasions where the gear won't engage. It could be happenstance that the tips of the synchronizers are aligned. You just let off the stick and reengage.

Going back to your original problem, grinding is typically a sign of worn synchronizer rings. They are made of brass. I hope you didn't put any non-approved, sulfur-bearing lubricant in the gearbox.

Typically, it's the first gear synchro that gets beat up the most. I developed a technique where I shift into first just before the car comes to a stop. It's easier to engage the first gear synchro with the car moving (ever so slightly) than at a dead stop.

 

[tadaima]

Wonder why it is this problem, so are you saying 5th gear is uselss when high revving?

Well I do notice too that its easy to get into first when coasting towards a stop.

Well i will try to change to MTL this weekend and see.

 

[Ma-fia]

Whimsey, MTX-75 is the tranny I've got in my Focus. I've heard a lot of good things about different types of fluids (Redline, smth. else), but everybody says that the OEM fluid works miracles with this transmission. And since I plan on keeping the car until either I or it dies, I think it's worth investing. After all, you don't change the tr.fluid every 3K. Do you remember how much you paid?

[ January 26, 2004, 09:27 AM: Message edited by: Ma-fia ]

 

[tadaima]

yea i dont change my tranny fluid every 3K, I would want to every 10K or year. If you do it yourself it's cheap.

Usually places charge $40-$60, depending on the place, once I got charged $16, because I was lingering around the garage and had to help one of the mechanics lift a new barrel into the oil pump.

I would of done it myself, but I couldnt get enough leverage to break the fillter bolt while being under a scissor jack.

 

[Bob Woods]

I was just at a used book store and the Honda manual stated that MTF is similar to 10w30/10w40 but that the MTF is reccomended.

http://www.fourthgenhatch.com/trannyfill.html


The safe choice is the Honda MTF but many
people (myself included) use Red Line MTF. 10W30 motor oil was spec'd for years but it was never a good choice to lubricate a syncromesh transmission.

[ January 26, 2004, 04:30 PM: Message edited by: Bob Woods ]