foild

hey guys... whenever i downshift into 2nd, i allways have a tuff time pulling it into gear... sometimes, however, it doesn't seem to give me any trouble.. It also does the same thing from 4th -> 3rd, but not as much.. This is something i can live with, but im wondering if there is a quick fix?


thanks,

Cam

Madrx7racer

i have that prob when I downshift into 2nd.......i think my foot is faster than my hand.......happens at higher RPMS whenI revmatch and put it into 2nd and it makes a nasty sound.

staticguitar313

iTrader: (2)

i have alot of trouble with various shifts, mostly its upshifting into 3rd, and its driving me ******* insane

TitosToy

i grind when i upshift to 3rd when revving past 4500rpms and shifting quickly. but i can live with it. as for a quick fix - uh.......i think i can speak for everyone when i say this... I WSHED!!!!! the only way to fix it is to rebuild the transmision with new syncros.

IaMtHeRuThLeSs1

Is everyone rev matching? I hope so.

Make sure that your clutch fluid is filled also, when mine was low it hit synchros pretty easy (clutch slave was leaking, replaced it last weekend)

It may be a good idea to drain your tranny fluid also, you may have a lot of metal in there from hitting your synchros.

Aaron Cake

iTrader: (1)

2nd gear syncro problems are notoriously common. Also, many cars will grind going into 5th. Just the nature of the beast. Fix it by rebuilding the tranny.

For the record, my first transmission had the 2nd gear grind. My next one didn't, but did grind going into 5th. My 1st gen also had the grind, but only going into 5th.

Madrx7racer

i notice the5th gear grind when I am coasting downhill in neutral and I put it into 5th when i lose momentum......

Turbonut

iTrader: (1)

As Aaron has stated.......Just the nature of the beast. On my S5TII, I purchased new, the dealership replaced the syncros at 85,000 miles under an extended warranty. I had the syncros replaced again at 155,000 miles when the engine was installed. They weren't exceptionally bad, but would grind if rpm's were higher than normal, so I had it rebuilt.

foild

i try to revmatch, but something inside of my head tells me its producing strain on the engine.. someone slap me and let me know how to do it properly.

plus, i never have problems getting into 5th

its sometimes 1 - 2 , sometimes 3 - 2, and thats about it.. 1-2 happens when it is cold, or i am accelerating quite fast in a race or something, an di shift when i hit 6800 - 7000 rpm

i was thinking draining the tranny fluid, an filling with some redline mt-90 or whatever its called... would this be worth the money as apposed to filling with regular tranny fluid? - i am having my cluch replaced this weeke,d which is leaving me with next to no money, but i might as well refill the tranny when replacing the clutch...

ajsuper7

on my 87 s4 i sometimes would get a grind going into 2nd at wot. as for missing/grinding 3rd i looked at a computer generated diagram of the 2nd gen tranny that was interactive and showed how the gearbox works when you shift, it takes a little longer for 3rd to mechanicly engage than 1st to 2nd or 3rd to 4th so you have to give it a little bit longer before you let the clutch out going from 2nd to 3rd

trochoid

iTrader: (6)

Upgrading to a premium tranny fluid may help buffer the shock load on the gears and syncros, and make the shifts appear smoother, and may prolong the inevitable rebuild. Rev matching and double clutching helps also.

In my opinion, the 7's tranny just isn't made to hold up well to high rpm speed shifts. Once the wear/grinding starts, you work around it until you either renew or reolace the tranny.

foild

so using redline tranny fluid shows no noticable improvement over adding premium tranny fluid?

Needa13b

When shifting with bad synchros, the most important part is to DOUBLE-CLUTCH! Revmatching is worthless unless you release the clutch pedal while in neutral. What happens is, say for example, when you are cruising in town in 4th gear, doin 30 mph. You want to go into 2nd really quick, you need to push clutch pedal, take gear out of 4th and into N. Here you NEED to release the clutch pedal, the clutch(engaged) will grab onto your input shaft, now you have control over how fast your input shaft is spinning. By reving to 3500 rpm while in neutral you are spinning your input shaft to match the countershaft speed that is driven by your coasting wheels. Once you match your RMPs to your Wheel Speed,(conversion formula below) push your clutch pedal in and take from N to 2nd. If you did it right, you will feel like there was absolutely no resistance at all. Once in 2nd and you release the clutch pedal there will be no jerking because everything is spinning as it should be, and you can accelerate smoothly.

--Basically you are doing the synchro's job for him, because he's been beaten to death by people abusing him, and he quit, now it's your job wether you like it or not.

After practicing you should just feel or hear where your engine needs to be at. When i first started I drove in 2nd (my problem synchro), starting at 2000rpm and drove up to 5-6000rpm noting how fast the engine was at each of the important speeds i wanted, 30mph, 45mph, 55mph.

In 2nd Gear- ('86 N/A)
30mph ~ 3500 rpm
35mph ~ 4000 rpm
40mph ~ 4500 rpm
45mph ~ 5000 rpm
50mph ~ 5500 rpm
55mph ~ 6000 rpm
60mph ~ 6500 rpm

Generally 30mph-45mph are right on, the more extreme the less precise my numbers are, but this way is a good way to remember them. Just add 5k to how fast you are going.

Needa13b

The gear difference between 1st and 2nd is huge compared to the other gears. If you start from a dead stop. Redline 1st gear, and then try to go right into 2nd with out a properly working synchro, you are gonna hear a terrible noise. 1st gear for me at redline gets me going about 45-50mph. So when I shift from 1st to 2nd, I have to take it out of 1st, then release clutch pedal in N, wait till RPMs drop around 5000, then clutch pedal in, shifter into 2nd. This one needs to be quick as the RPMs are dropping fairly rapidly.

foild

seems like you would lose so much time shifting to N, then reving, then going into gear when you are racing...

i always though you just match revs while shifting from 3 - 2, i didn't know you had to go to N and rev, then push lcutch pedal in and switch to 2nd..

wow i learned something today at work

Stanello

iTrader: (1)

I have a tough time getting into 2nd if its cold, and it almost never wants to go from 5 to 4. Yes I rev match.

jgrewe

iTrader: (1)

Needa13b just gave a nice clinic on downshifting. Thats what its all about. And in racing situations its the best way to make these trannys last. Under heavy braking you have one foot working the clutch, one foot working the brake, and your other foot working the gas. Wait thats three... Oh yea heel and toe braking! Practice that on the street and you won't need synchros(to much). It becomes second natureand it seperates racers from ricers.

Busted-7

My 7 tought me to heal toe because it wouldn't idle and would die otherwise. THe best way to learn a technique is out of necessity.

jgrewe

iTrader: (1)

That is so true!!! Next time I do any instructing I wonder if I should have my students mess up their idle settings!?!?

Needa13b

This is so true. You don't know what a good thing you have until your synchros go bad. Then you adapt and become a better driver for it. Blessing in disguise? RX-7 Gods are smiling.

torean

ok...so i take it that everyone here has a bad transmission?.....im actually planning to rebuild mine this summer....time permitting...school and all..but i would really like to "practice" on a test subject first before i totally distroy my almost dead tranny.....who knows..if i can master the art i may offer my services here......anyone wanna donate a spare?

beefhole

iTrader: (29)

I grind at least once a week going into 3rd , and 5th kinda grinds but that's because it's a much higher ratio and the throw is longer, so I gotta take my time going to 5th (especially when shifting from 2nd to 5th doing 60+ MPH )

buttsjim

I've always been of the opinion that the absence of reciprocating mass in the rotary engine requires driver patience on upshifts--or else you beat the syncros. A piston engine starts to slow immediately when you push in the clutch, so that you often have to give it a little throttle to match revs for the next gear. The rotary, on the other hand, just wants to keep on spinning, so that the driver needs to wait a moment for the revs to drop enough to match revs for the next gear. I expect an overlooked advantage of using a lightweight flywheel is that its reduced momentum allows the rotary's revs to drop more quickly between gears, thus smoothing shifts.

Just my opinion.

TitosToy

When shifting with bad synchros, the most important part is to DOUBLE-CLUTCH!




that's a good and probably the best way to shift with bad syncros. but alot of speed demons here (like myself) feels double clutching takes long so what i do is as the revs go up and i wanna change gears (up or downshifting) hold the clutch down and let the gears catch on its own. imo it's a lil faster than doulbe clutching cuz it saves time from pressing and depressing the clutch, and you can still rev match. but all trannies are different pending on abuse of drivers. try it.

Tito

TitosToy

i agree because the piston's lower-end torque it produces slows the revving in no throttle as with the rotary it can produce the same amount of torque but at a higher end. i know a lighter flywheel revs faster but wouldn't it make it spin more longer due to less rotational mass?

Tito