300tdi Speedometer / Transducer

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19_Hue_95

19_Hue_95

Active Member
Posts
100
Location
Midlands
A few weeks ago the speedo cable failed so it was replaced ('97 300tdi defender). But with the new replacement it seems to bounce quite wildly up to 40'ish then works fine.

Since then I've got a clicking sound behind the dash of our '97 300tdi Defender. It seems speed related and I think it's the speedometer needle bouncing in the dial - I've also do a lot of rough corrugated tracks abroad recently so could just be something loose in the dash.

I've been told that it might be the transducer (?), never even heard of one of those - can anybody point me in the right direction of what it is, where its located, how easy it is to change etc.


































































I had the speedometer cable replaced a few weeks ago
 
The square bit of cable might not be inserted into the speedo head far enough which might be why it’s jumping and clicking
 
The speedometer on a 300tdi is cable driven.
In the transfer box, behind the handbrake drum there is a plastic wheel, engaged with a cog that spins a pin which has a square hole in the middle.
The square cable that it spins fits into a square hole at the back of the speedo.

The cable spins and the speedo displays a speed.
On the newer Defenders (TD5 etc) the speedo is all electric and instead of a square cable there is a transducer that sits in the square holed pin (same place, behind the handbrake drum) and produces a voltage which is fed to the speedo.

The square cable can be easily dislodged and not sit in the square holes correctly causing it to jump and click and send the needle bouncing around.
Take it back to the person who fitted the new speedo cable - it's not right.
 
Sorry to butt in, does the bit that the square end of the speedo cable sit in on the transducer come out? Our cable has broken right on the end of the square peg that goes into the transducer, and now we can't get the square peg that should be attached to the end of the speedo cable out. It looks like there is some sort of threaded thingy around it, does that come out, so we can get the square peg out without taking the whole box off? So little room between that and the handbrake drum, very frustrating.
 
Take the rear propshaft off (9/16" spanners), loosen the handbrake shoes nut on the back plate of the handbrake drum), remove the countersunk screw and pull off the handbrake drum.
Remove the 4 bolts that hold the drum onto the output shaft of the T'Box and rest it, (out the way) on the chassis rail.
It takes less that 15 mins to get it off and isn't a hard to do job.

Now you can clearly see/get at the speedo drive.

If you spend another 10 mins cleaning up the handrake drum and checking all is well with the shoes etc, when you reasemble to hand brake will be a lot better ....
 
here's what it looks like ... (mines a cable not a transducer)

speedo-drive-1.jpg

speedo-drive-2.jpg
 
Thanks, we just got to that bit, and are now trying to get the speedo drive gear out so that we can get the end of the speedo cable out of it. Yours looks a lot cleaner than ours though, and our bolts were knackered, so some more replacement parts!! Post woman thinks we are building a landie by post, and she is probably right. More shiny bits to look at once it's done. You have been a brilliant help. Wish you could have done it for us, but once again hubby has scraped knuckles and black hands.
 
Did you take it all apart just to help us, or were you doing some other job at the same time? Bless you if you just did it for us to see what we were dealing with.
 
I'm putting in a new/refurbed one with a different ratio.
Mine looks cleaner cos it's all new.

The 'round drive unit is clamped in with that fork-clamp. It has a lip on the top. Using a flat bladed screw driver with the fork removed, you should be able to ease it out.
There is a rubber O ring seal about 5mm down, you may need loads of penetrating fluid to help grease it's passage ...
 
I am more interested in doing it with hubby now I know there are all sorts of innuendo I can use when he is doing it!! A bit like when you bleed the breaks eh!!
 
Speedo drive gear is out, and the end of the cable is still stuck in it. So new one on it's way. Shame as the drive gear itself is in good nick. Thanks for your help, thanks also to sierrafery for his tutorial on how to get it out. Much appreciated. Well done for saving another landrover from certain death by fire.
 
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