hi all i REALLY hope u guys can help im allocated my cf and since iv had it its had is gearbox recon’d 4 times in a little over 6 mths and its gone again heres my dilemma .
When its driving it slips outof high range and will not drop back in. you can here the splitter drop when you try to lift the clutch this is the reason for the recons how ever the fault keeps returning it wont have any problems in low range but high is a nightmare any1 else had to deal with this if so any suggestions. we have another truck with the same problem but its not so bad but i just no im going to be asked to drive that one while i dont have mine.
It could be something as simple as a faulty switch or relay. It isn’t uncommon for a mechanic to go for the most complicated possibility first and overlook the basics. I’ve seen plenty of electronics, electrical and auto-electrical engineers go tearing stuff apart to try and find out why it doesn’t work but have forgotten to check the fuse in the plug first which ultimately turned out to be the problem.
Unfortunately there’s a few external things it could be but without access to the vehicle its stabbing in the dark. Modern trucks do seem to have quite a lot of electrical gremlins nowadays compared to days of old as wiring looms get more complicated and routed through ever smaller gaps. Just let them deal with it.
It isnt electrical i dont think its a physical problem of it slipping between the boxes leaving you in netural but if you try to put it back into gear it “slips” back in the middle 9/10 now seems to be worse wen loaded just waiting for someone to unload me to see if it will make the 35 miles home
nosmaster:
hi all i REALLY hope u guys can help im allocated my cf and since iv had it its had is gearbox recon’d 4 times in a little over 6 mths and its gone again heres my dilemma .
When its driving it slips outof high range and will not drop back in. you can here the splitter drop when you try to lift the clutch this is the reason for the recons how ever the fault keeps returning it wont have any problems in low range but high is a nightmare any1 else had to deal with this if so any suggestions. we have another truck with the same problem but its not so bad but i just no im going to be asked to drive that one while i dont have mine.
First question is .You mention range and split ,that makes it a 16 speed ZF box ,which is confusing as ,from what I remember you should have a 8 speed no split ,range only…I may well be wrong ,but if you can clarify if you have 1 or 2 buttons on the gearlever ,then I can take it from there
my bad thats bad wording i was stressed on the side of the road its a 8 speed “zf box” i believe it keeps slipping between the hi and low wen pulling but it got to the point where it would slip instantly and then when you pull back to neutral you here the range lift back into high ,rinse and repeat gave up in the end and got recovered when it was in the air i had a look underside and it looks like its blown its oil everywere and its dripping from the bell housing. Had a recon 8 weeks (ish) ago
If it is blowing oil everywhere then it may just be a seal behind the piston pot…When it is in high air may be leaking and pressuring the inside of the box…
Other problems may be that with it jumping out of high the synchros may be shot
If it is actually going from high and in to low itself ,then that would be an electrical fault,as when there is no power it will default to low
None of it is difficult to check,with it being an old box the breather may also be blocked which may also cause the box to pressurise ,so you may have 2 issues
For the range ,the only the range needs removed,not the whole box,The job is a piece of ■■■■
Is it the dealer or a independent hat does your work…No need to mention names
Were only a small 4 truck show so a small indipendant its been done 3 times before i think this is number 4 last time it came back with no reverse sensor someone put the shaft in the wrong way round so it didnt fit
It is impossible to fit the forks incorrectly,you wouldn’t get it together ,The difficult bit now is ,for a small operation do you persevere with your current repairer with the gearbox ,or take it to someone else…And obviously strike a deal ref compensation,even if they take the box out.
If it is constantly jumping out of high and leaving you with no drive ,until you press the clutch ,your synchros are shot
A way I try to make it simple (even burger king should understand it ) think of it as an 8 speed bike…You have 4 gears on the wheel .that is the main 4 gears in your box ,and the range is the 2 gears on the pedals and that is it apart from the range is electrically pneumatically operated
Got word back today the range was leaking so i guess you were right about it pressurising anx blowing oil there waiting on a part should have it back early next week
I.ve got the seals in my toolbox ,could have had I done in a couple of hours …most difficult part getting the old oil seal round the range shaft out…Hopefully that is all it is ,but you fill find out pretty quickly …Id suggest they also change the breather,and the oil seal that blew the oil over the box
