grinding into reverse

[samzhot240]

So ive had my car on the road for three years and for three years ive had to deal with it grinding into reverse. The throw on the pedal has been played the master and slave cylinder replaced and the clutch and pressure plate taken out and looked at. if anyone out there has any advice no matter how strange it may sound please pass it along i'm quite desperate to save reverse. thanks, sam

[doradox]

So ive had my car on the road for three years and for three years ive had to deal with it grinding into reverse. The throw on the pedal has been played the master and slave cylinder replaced and the clutch and pressure plate taken out and looked at. if anyone out there has any advice no matter how strange it may sound please pass it along i'm quite desperate to save reverse. thanks, sam

Usually one would start with the basics. Be a little more specific about what you've done with regard to the pedal free play. Make sure the clutch master and slave have the correct bore sizes . Make sure the system is properly bled. When the clutch was out how exactly was it "looked at" to determine that it was ok to re-install? Was the pilot bearing checked?

Steve

[samzhot240]

we tried to adjust the amount of throw on the pedal by moving the hole fro the pin that connects to the master cylinder because it didn't feel like it was completely engaging but it really did nothing except make it even more difficult to put into the other four gears. the system has been bled several times and i'm quite sure that the master and slave cylinders are no longer the problem. My father looked at the clutch to check if it was warped and had it looked at by a local technician, He also tried to gauge as best he could to see if the pressure plate was ok and from what he could tell (he is quite mechanically inclined) it all seemed to be fine.

[doradox]

Do you have a service manual? What is the clutch pedal free play. Did you check the pilot bearing?

Steve

[samzhot240]

the free play is like 3/8in and the throw out bearing has been replaced and the flywheel and clutch were checked for trueness with a dial indicator.

[doradox]

Pilot bearing? Has this problem existed the entire time you have owned the car? Was some work done and then this problem appeared or did it just happen one day?

Steve

[Carl Beck]

How many miles are on this transmission?

If your clutch works fine in all forward gears - it is most likely not your clutch.

Reverse is not synchronized - - when the transmission are well within factory spec - this is not a problem, because you have to come to a full stop, before engaging reverse.

As these transmissions acquire 100,000+ miles the bearings/shafts and synchronizers wear - and it takes reverse gear a bit longer to stop spinning.... this is not all that uncommon.

Could be your transmission is simply in need of a rebuilt.....

FWIW,

Carl B.

[Walter Moore]

My 4 speed transmission did that every time that I put the car in reverse. I ended up replacing it (for other reasons) with a 5 speed, and the new one does not grind going into reverse. I didn't even touch the clutch when I changed the transmission, so my experience agrees with Carl's advice.

[doradox]

A slight clutch drag will cause grinding going into reverse but the synchronizers will overcome the drag and forward gears won't be a problem. That's what synchos do. Slow down or speed up the input shaft so gears can be shifted without grinding. Something has to cause the input shaft to be turning in order for reverse to grind. A worn out transmission can't do that. Transmissions don't turn themselves. A dragging pilot bearing will do it or a dragging clutch. If he's whipping it into reverse too quickly before the input shaft can stop then that's driver error not the fault of the transmission.

Walter, I assume you cleaned the input shaft when you installed the transmission. You may have been dragging the pilot bearing or the disc couldn't move on the splines and stayed in contact slightly with the flywheel when the pressure plate released with the old trans. Cleaned up, those things would be less likely to happen.

Sam, try these things:

Try shifting into a forward gear before quickly shifting into reverse.

As Carl said be at a full stop.

Wait a moment with the clutch pedal depressed before whipping it into reverse.

If it still grinds your clutch is dragging.

[jorde]

I have a very similar problem with mine. I know its not correcting the problem but it stops mine from grinding. Step on clutch, shift into first then go into reverse. don't move the car though, just work the shifter through 1st gear first before going into reverse. it stopped my grinding completely. like i said it doesn't correct the problem but it stops that awful grinding.

[JonnyRock]

I have a very similar problem with mine. I know its not correcting the problem but it stops mine from grinding. Step on clutch, shift into first then go into reverse. don't move the car though, just work the shifter through 1st gear first before going into reverse. it stopped my grinding completely. like i said it doesn't correct the problem but it stops that awful grinding.

This is what everyone should be doing with just about every manual tranny.

Your tranny does not have a reverse synchro. Therefore you should shift the lever into first before engaging reverse. This matches the speed of the transmission to the speed the engine is spinning.

You should really throw it into first and not a different gear though because reverse and first are the most closely matched ratios. You don't have to move the car forward in gear, but you can. Just going through the motion will shift the fork and allow the first gear synchro to do it's job. You shouldn't need to 'quickly' shift into reverse either. Normal speed will do.

If you're regularly grinding reverse because you don't let the transmission match speed, you're destroying your tranny.

Edited April 14, 2009 by JonnyRock

[doradox]

I have a very similar problem with mine. I know its not correcting the problem but it stops mine from grinding. Step on clutch, shift into first then go into reverse. don't move the car though, just work the shifter through 1st gear first before going into reverse. it stopped my grinding completely. like i said it doesn't correct the problem but it stops that awful grinding.

Shifting into a forward gear before quickly shifting into reverse is a common trick to stop grinding. It was used much more back in the day when we had transmissions that weren't synchronized in first gear in addition to reverse. You'd push in the clutch, hit second, then into first. I still often do it out of habit.

Steve