rhydgte Posted April 23, 2009 Share Posted April 23, 2009 My fathers 300TDi Auto has developed a fault in the auto box it now only selects 1st and reverse. This just 'happened' and has been perfect until now.. It has covered 75k. It has always had regular oil changes etc.. Any ideas?? Quote Link to comment Share on other sites More sharing options...
Dave W Posted April 23, 2009 Share Posted April 23, 2009 Is this when the gearbox is "warm" or when it is cold ? Sticking regulator or split O ring on the regulator/governor will cause this but normally it only does it for the start of the journey and then, as it warms up, it starts working again. My old Range rover wouldn't change up from first for a couple of miles... was a bit embarassing as we're 500 yards from a 40 limit ! That was a split O ring. Quote Link to comment Share on other sites More sharing options...
rhydgte Posted April 24, 2009 Author Share Posted April 24, 2009 Is this when the gearbox is "warm" or when it is cold ?Sticking regulator or split O ring on the regulator/governor will cause this but normally it only does it for the start of the journey and then, as it warms up, it starts working again. My old Range rover wouldn't change up from first for a couple of miles... was a bit embarassing as we're 500 yards from a 40 limit ! That was a split O ring. Seems to be when cold, gears 're-appear' after about 5 - 10 miles.. How easy a problem is this to sort out?? Quote Link to comment Share on other sites More sharing options...
Dave W Posted April 24, 2009 Share Posted April 24, 2009 It will mean taking the transfer box off but it can be done with the auto box in situ. The governor assembly is located at the end of the gearbox. If you get the serial number of the box you can get a replacement governor assembly and O rings fairly cheaply... IIRC it's about £40 or so but it's been a few years since I last bought one. You might get away with just cleaning the existing one in which case just check/replace the O rings. You don't even need to drop the oil out of the ZF as everything you need to get to is outside the gearbox itself, it's just covered by the extension/adaptor housing that adapts the ZF to fit the transfer box. You remove the extension housing and the output shaft adaptor and you'll see the parking pawl and ring. The governor is bolted to the back of the parking ring, you can slide the whole assembly off the output shaft, replace the governor and O rings and put it all back together. The governor is essentially just a weight that controls oil flow using centrifugal force, if it sticks or the O rings that seal the oil into the 2 "chambers" around the output shaft are split it messes up this speed detection, especially when the oil in the gearbox is cold. Getting the transfer box off and back on again is the biggest part of the job. If cleaning/replacing the governor doesn't help and there's no obvious damage to the O rings, if the problem persists you'll need to think about a recon box. Often a sticking governor is caused by sediment (bits of brake material) building up in the box and, if that is the case, it's probably a short term fix. It's not unusual for this sticking to occur after a gearbox oil and filter change as it "disturbs" all the sediment and washes it around the gearbox is relatively low mileage (the ZF in Pam's 90 has done around 180,000 miles now without being touched other than an enforced oil change due to a split oil cooler pipe. Quote Link to comment Share on other sites More sharing options...
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