handydandy

i was wondering are there synchros on the R for the tsx?

i recently grinded into reverse at a standstill without pressing the clutch in at all.
ive heard that the R does not have synchros.

i know that when you grind, it messes up the synchros, but if it doesnt have it, what does it do?

psteng19

Why would you be shifting into reverse without the clutch, synchros or not?

handydandy

i did it on accident....but just wondering anyways.

waTSX

If the tranny still works OK, I wouldn't sweat it. Just don't do it again

ILoveMyHonda

No there are no syncros on the reverse gear.

Its a direct input shaft and counter gear in most cases.

It's also straight toothed gears, which is why you get the whinning sound when reversing.

Un-Kut

anybody know why i reversed at full acceleration and this burning smell came? everything was done properly too, full stop, clutch than gear in.... weird...

SicK TypeS

anyone grind when shifting into reverse when the car is rolling forward?

aaronng

Yes, that happens as long as your car is moving.

n8dog82

ok guys, I know this forum is known for being kind and helpfull and not flaming eachother.....but this thread is RETARDED. And not just one person, but three stupid questions from three different people.

1. Why would you ever need them? Of course there are no reverse syncros, or else you would be able to shift into gear at full speed. You only shift while stopped, hence not syncros needed.

2. of course it grinds if you go into reverse if you are still going forward, because there arent any synchros. are you that impatient that you cant wait till you stop? or do you want to do a kickass rockford?

3. why are you flooring it in reverse under what you call full acceleration?? That may be the dumbest comment of all.


ok, I am done now, sorry for the rant.

Brandon24pdx

you didn't hurt anything. transmissions arent that easy to damage, but they can make some pretty rotten noises if you do stuff like that. R isnt synronized, and is a straight cut or "spur" gear. (As opposed to 1-6 which are called "helical" gears and are all syncronized.)

Brandon24pdx

now that you're really not supposed to do...can damage the tranny and even says so in the book. Right foot on brake when shifting into reverse

ILoveMyHonda

One day, we had a customer that came into the shop complaining that, when he would reverse the gear would pop out.

So we tried it and of course, "could not duplicate problem"

So the cuztomer comes back in to pick up his car, gets a lil peeved at the service writer that I didnt reproduce the problem. So I say "show me".

SO the customer gets in starts the car, takes me to the lot in back, puts it into reverse, AND FLOORS IT!! after like 15-20 feet it pops out.

I turn to him, IT'S NOT DESIGNED TO DO THAT, DO YOU RACE THIS VEHICLE? After that I just let him take it up with our Shop manager. But man some people.

The funnier thing was he came in earlier that month and complained his clutch burned out prematurely. We fixed it under warranty, we knew something was up but couldn't prove it, but we got the answer that day. Sheesh

Sorry just thought I'd share.

aaronng

^^ LOL!!! And here I was about to try to hit vtec in reverse...

SoCaliTrojan

Imagine one shaft connected to your engine, and another shaft connected to your wheels (output shaft). When you put the car into gear, the layshaft connects the engine's shaft to the output shaft, thereby letting the engine drive the wheels. All the forward gears are spinning in one direction (because of the layshaft). In order to engage the reverse gear, an idler gear is used between the reverse gear and the gear on the layshaft (otherwise the reverse gear would spin in the same direction as the forward gears and will simply be another forward gear). That way the engine can keep going forward while the wheels go in reverse. The idler gear rotates in the same direction as the other gears, and the reverse gear spins in the opposite direction.

The forward gears are helical gears (ie: angled teeth). This allows them to engage gradually as well as run quietly. However, helical gears are harder to engage (remember, they have to engage gradually...so you'd have to be rolling in the right direction). For the reverse gear, spur gears are used (which has straight teeth). These are easy to engage.

As mentioned before, the reverse gear needs an idler gear to reverse the spin rotation between the layshaft and output gear. All 3 gears (idler gear, the gear on the layshaft, and the gear on the output shaft) are spur gears so that they can be engaged easily (like while you're stopped). When you shift to reverse, the idler gear moves up to mesh with both of the other gears at the same time. If you're still rolling forward, then one gear is still moving (in the wrong direction, no less), and the idler gear won't be able to mesh with the output shaft. Imagine a desktop fan blowing at slow speed (with the finger guard off). Next try putting a pencil in-between the fan blades by moving the pencil in the same direction as the fan blade's rotation. Next, try doing it while moving in the opposite direction. The pencil is the idler gear's teeth, and the fan blade is the reverse gear on the output shaft. It's much easier to do it if the gear isn't rotating in the wrong direction...wouldn't you say?

As an interesting side note, reverse gear makes that whining sound because of the spur gears...whenever the gear teeth engage, they are actually colliding with each other. Basically the whining sound is the string of sounds from the gear teeths clashing...which is one of the reasons why they prefer to use helical gears for the forward gears (it'd be annoying to listen to the whine at all times)

As for synchro's for the reverse gear...it's not needed. Synchro's are for when you want the gears and the collars on the shaft to match speeds before they engage the teeth. Since you need to be stopped (as mentioned earlier) in order to engage the idler gear, you don't need a synchro to match the reverse gear's speed (0 rpm) to the output shaft's speed (0 rpm). Imagine a stunt where-by you had to jump onto a bus traveling at 30 mph. You'll be in a car and will jump over to the bus. The car acts as a synchronizer to let you (the collar on the output shaft) gain enough speed to safely mesh/land onto the bus. Now imagine the same stunt at 0 mph (while you're stopped so that you can engage the reverse gear). Is the car really needed for you to gain enough speed to jump onto the bus? I don't know about you, but I think I can jump onto the bus just fine without the car (or else we'd all have an interesting time at bus stops). Thus, synchro's are useless for reverse gears, and will never be used anyway (why add an un-needed part?)

As for accelerating in reverse at high speeds...imagine all 3 spur gears clashing at such high speeds. I'm not surprised that the gear pops out at high speeds. The teeth on the layshaft's gear will be smacking the idler gear's teeth, which in turn would smack the reverse gear, which would then jerk the output shaft's collar's dog teeth out. Spur gears aren't meant for high speeds (helical gears are)....they are used so that we can actually engage the reverse gear at a full stop. Reverse is only to allow you to move your car in reverse...not to drive on the road backwards.

ChrismanTSX

nice explanation and analogies! i think the n00bies will get that! thanks!