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21 Turbo Un1 gearbox

Haz

Well-Known Member
I've always had a problem with 1st to 2nd on the box in this 21. If driving lazy it will catch the gear but there isn't the click-clunk that feels like a positive gear selection like the other gears.
If changing gear at high revs, regardless of boost level, 2nd is simply not there and just grates the gears.
The box has been sent off for repair. He says the internals are really good compared to others he's done in the past with the only possible fault being a tooth on 3rd was chipped and the chip may have interfered with the gear selection. Some other items replaced but not regards faulty 2nd.
Box back in the car and getting chance to test it properly, it's no different. I have noticed some gearstick wobble with hard acceleration-off-back on so am now assuming something has play and 2nd is just out of reach as I try to engage. Engine/box mounts are a bit feeble, box ones are missing the big O rings but they all seem to be doing their job. I plan to change them but I would have though it would be a known common fault if it could be the mount.
The 2 stick to box linkages are looking like the culprit, the one with plastic ball joint sockets seems ok but I can't really see the rubber ones causing this much of a fault?
Suggestions?
 
If the box internals have been given the all clear then the most likely things are the change rods or clutch clearance issues.
My car sometimes suffers from what I call a lazy clutch where your request for a rapid dis-engaugement & selection is hindered buy the speed which the hydraulics react,
Check the clutch fork for cracking & distortion plus movement which should be 11-12mm with no wear on the arm pivot points.
If possible change the hydraulic fluid and look for signs of leakage.
 
That's kinda what's happening Andy but I figured I'd have read about it if it was a common thing.
That makes sense red. I'd not considered the clutch as it's always 1st-2nd. Fork is fine, travel I've not measured but around that, maybe more. I'm sure I had the occasional clutch slip when down shifting to bring the boost up quicker, off the throttle and back on and it was gone, only happened once or twice though. Not really put it through its paces to notice it happen with every gear change.
Fluid is new but I'm not convinced the piston is sealing correctly but I've been told there's none new or another breed that shares the same part.
Modern upgrade with an adapter plate is the way to go I guess.
 
You have to watch it on the slaves as some have deeper/different inlet ports for a plastic pipe,as above listing for trw pj117 .These have a sleeve/compression ring type fitment where the Turbo ones are a rigid pipe .
 
As Lee says, I don't think they're correct Andy although easier to find.
If it is just the pipe fitting that's not an issue but I wasn't sure if there was any difference in piston travel?
 
Quadra boxes are different to 2wd. The UN7 is a lot more sensitive IMO, the synchro's dont like fast shifts much.
The UN1 is a lot more sympathetic, Haz you definitely shouldn't have what you describe. The only thing i can suggest though is sending it to Chris Cole for a rebuild, at £350 everything gets done and it comes out like a new box. It doesn't sound like hydraulics to me tbh. Try the pedal pump trick to see if it improves the situ. I doubt it will though.
 
Brill, it says on back order, how do I order a set? Thanks
The guy I've had it checked over by is Pete at GEARS, supposidly good with these and type 9's and the likes. As the problem hasn't changed I'm ignoring the box for now.
It just feels like when engine mounts are gone and it all jumps around, think i need some more miles of experimenting.
 
I'm only had chance for a little testing but I'm thinking it may be a box problem but without seeing how it operates internally I'm unsure.
It seems at lower revs I'm moving the gearstick slower, if I try to change quick the problem is there, so I'm moving faster than the box likes.
First back into neutral seems to be positive but pulling from neutral to second is where the fault happens.
The stick won't move any further into second and if held in position it just grinds the gears. Something isn't lining up properly, I think the syncro is but not the gear, or the selecter fork is worn.
 
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