Gearbox Problem

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Fri 25 Apr 2003 13:33
Gearbox Problem - charlie_boy
I have bought an Astra 1.7TD GLS 1993 Reg (Isuzu engine). The problem is that when driving, gear changes 1,2,3,4 & 5 are pretty smooth for the age of the car, but come to reverse, you have to crunch the gear into place (sounds pretty awful, I know!). However, when the eninge is off and you cylce through the gears, reverse is easy to obtain. The clutch enages pretty low down to change the gears. Would a clutch change solve the problem or is it a big job. If so how much to rectify the problem.

All help appreciated.
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Fri 25 Apr 2003 14:14
Gearbox Problem - Dynamic Dave
How high is the clutch pedal at rest. The correct setting should be marginally lower than the brake pedal.
What might help is selecting 2nd before selecting reverse, or waiting a couple of seconds after engaging the clutch before trying to select reverse.
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Fri 25 Apr 2003 14:24
Gearbox Problem - charlie_boy
It is pretty low at rest. Does it sound like a clutch problem? If so how much.



Please don not say I need a new gearbox!!
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Fri 25 Apr 2003 14:33
Gearbox Problem - Dynamic Dave
If the pedal is too low; at best the cable needs adjusting, at worst the cable needs replacing as it's stretched too much. The cable can be adjusted by turning the nut at the gearbox end of the cable. IIRC, mentioned in the Haynes manual is a distance from clutch pedal to steering wheel for the correct adjustment settings.
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Fri 25 Apr 2003 14:39
Gearbox Problem - charlie_boy
Why are the other gears ok, but reverse is pretty damn hard. Would this solve my problem.

P.S. You don;t live near Manchester do you??????
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Fri 25 Apr 2003 15:00
Gearbox Problem - Jonathan {p}
I had this same problem on my recently departed saab 9-5. it required a new reverse gear as the brass ring around it had worn to the extent that it wasn't slipping into the gear as it should.

Saab gear part cost £175. Labour was £300.

They had to take the gearbox off to do it, so I had them check the clutch plate and master and slave sylinder at the same time.

Jonathan
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Fri 25 Apr 2003 16:26
Gearbox Problem - Dynamic Dave
Why are the other gears ok, but reverse is pretty damn
hard. Would this solve my problem.


The forward gears are helically cut.
auto.howstuffworks.com/gear3.htm

The reverse gear is straight cut, so the teeth don't always align first time - hence the crunching.
auto.howstuffworks.com/gear2.htm
P.S. You don;t live near Manchester do you??????


Nowhere near, sorry.
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Fri 25 Apr 2003 19:55
Gearbox Problem - Another John H
Crunching in reverse as described is due to clutch drag.

The forward gears don't crunch because of the synchromesh - it's designed to get the coggery running at the same speed when you change gear.
In this instance the same speed is zero.

There is no synchro on reverse - crunch.
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Fri 25 Apr 2003 20:18
Gearbox Problem - Railroad
The clutch pedal should be level with the brake pedal or fractionally higher. Adjustment is easy, and done by lengthening or shortening the cable on the top of the gearbox with a plastic nut.

To avoid crunching in reverse, first select a forward gear, then without taking your foot off the clutch select reverse.
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