Gearbox help

[Praz Oner]

I'm in need of some help, so last weekend i swapped over my gearbox since the old one was crunching, i was told the gearbox i installed was mint, after installing a new clutch and putting it back together with new fluid and correct grade of oil it wouldn't select first unless i shifted into second or third then it will go in no problem. Straight away i thought it would be the gear selector linkage or something along those lines but they seem to be working fine, the bushes look fine also. I found that the gear selector bracket was abit sloppy so i swapped it over from my old gearbox. But that still didn't fix it. I do have a sloppy gear leaver from the previous owner modifying it abit but it always went into gear on the old gearbox... Any ideas?

 

[4piknup]

Any clutch drag?

 

[Praz Oner]

Nope no clutch drag, clutch fluid levels all good, flywheel has been machined. Neutral somehow ended up being first gear for a couple times so that was weird.. All the other gears are fine.

 

[evo-gsr]

Synchros are fucked.

 

[BMGTZ]

how long did the box sit around? Im thinking the synchro for first is sticky or seized. It MIGHT improve with a bit of driving. BUT don't dress in drag or you may get caught out if she blows up.

you can also try running some diesel engine oil in the box while all four wheels are off the ground. Run through first up to say 5000 and the take you foot off to allow it to lose speed. the second same...do this twenty or so times.

each time gently select first with the wheels spinning.IF it crunches alot...the box seller needs to answer some question

 

[Praz Oner]

Damn was hoping it wasn't the gearbox, it has been sitting around for a while so yes i think your right and yes will give that a try. Just hope it frees up.

 

[BMGTZ]

it has worked for me in the past. DO NOT DRIVE IT with the diesel oil in the box.

 

[Praz Oner]

Did it ever happen again to you or just the once? any troubles after running diesel oil in your gearbox?

 

[evo-gsr]

You only run it as described to free the synchro up..then dump it and refill with correct oil mate.

 

[Praz Oner]

Sweet thanks all for the help, hopefully this works!

 

[BMGTZ]

No..it was fine after the synchro was moving...the diesel oil has lots of detergent in it so will get rid of a bit of sludge. No trouble after

 

[EVO-00X]

Try raising the rpm with the accelerator to 1500-2000rpm, foot on clutch, then try gently shifting it into 1st to see if it slides in better in the meantime.
If it does then yeah, the first synchro needs replacing and you will need to raise the rpm a little bit everytime you want to go into 1st gear.
It could be several things really. Even a slight notch in the shift rail or end of the rail that doesnt want to slide properly can do it, loose or damaged keys and springs in 1st/2nd hub and slider, synchros etc.
Try Brian's method of cleaning the guts out and see if it works.

 

[Praz Oner]

Cheers for that mate, will try that tomorrow, took it for a good drive today almost every time i shift into second then first it engages. Maybe i could swap the first synchro out of my old gearbox and put it in this one.

 

[Praz Oner]

Quick question has anyone tried mb-l8 for a gearbox additive??