LS1 Gearbox Problems

[s_ikari2015]

So in the last couple of days I've had issues with my 6spd gearbox in my LS1 Monaro. First it was making noises like a slipping clutch. It would happen when it was cold and just started, in Neutral and when in gear with the clutch out. It would pretty much go quiet when I depressed the clutch.

Now it's having serious issues getting into 1st and reverse. I couldn't get it into reverse at all last night, ended up turning the car off and fiddling with the gear lever until it slotted in. I then started it in reverse.

This morning gear changes were hard and horrible, even had problems getting into 3rd. Ended up taking off in 2nd all the way to work as I didn't trust 1st.

I've read that there are common noise issues with these boxes, and that it's likely a gearbox bearing is causing the problem here. The clutch it fine, no pedal fall, no slipping at all. The problem is literally the gearbox. Selecting gears is difficult, sometimes not possible.

So, two questions.
1. What is the likely issue? (Synchros, a particular gear is gone, bearings?)
2. Are there any better gearboxes out there that are a quick swap for the std?

The car has done 120k.

[s_ikari2015]

*BUMP*
Dissappointed nobody has any suggestions.

[s_ikari2015]

Bump again...

really after something here people. It's driving me silly. It occasionally grinds and clunks trying to put it into 3rd, and when trying to put it into reverse sometimes it won't even go right of 5th/6th.

[lenLS1]

I have a similar problem. What did you do too get it fixed?

[Bargain Bucket]

I would check the spigot bearing in the flywheel. They seize/break up. Many a gearbox has been incorrectly diagnosed as faulty when it's just this simple part that has failed.

[BlackVXGTS]

The Holden service manual's suggestions are to make sure the transmission fluid level is OK, and if so, drain and replace the fluid. Myself and a number of other LSx owners now use Penrite Manual Gear Oil 70 instead of an auto trans fluid (but that's your choice). If that doesn't solve your problem, the next step in the manual's diagnostic charts for six out of the seven symptoms requires the removal of the gearbox.

[oscar03]

i have an rx7 had a similar problem that i solved really easily... turned out the hydrolic clutch was low on fluid and wouldn't dis-engage the clutch properly making it har to change gear. not sure if this is whats wrong with yours but its easy to check.
reverse was the first to start giving me troubles as well.
and yeah i know it was pretty bad on my part as far as maintenance goes.

[vncruzr]

have you been under the car and checked all linkages?