I’m still working on the finishing touches of the 84 XJS I acquired from my father who installed a 350 Chevy with a TH350 transmission. My speedometer wasn’t working and I discovered that there was no transducer on the transmission. I purchased one but when I go to install it I find that it fits into the “bullet” ok, the cable slips in fine and all but when I tighten up the large outer screw portion it bottoms out up against the transmission before it is able to tighten up the transducer. So the transducer is installed but with a substantial amount of play. You can wiggle it around quite a bit.

Is that normal? Is there a recommended way to fix that? Its a DAC 4569 stock transducer on a Chevy TH350 tail housing.

Thanks for any advice!
Anthony Finch

 

Not normal, must be fixed. I would pull the inner plastic gear and see if the square end of the driv cable is going home properly. If it is, remove the casting the transducer goes onto and assemble the thing off car and see where the play is. It might just need a spacer. I also just mention that on early HE XJSs the speedo was entitrely cable driven, so are you sure you have an electronic speedo head? . On early electronic cars the gearbox had a right-angled drive attachement on it, this converted the previous cable drive gearboxes - which could not take the transducer directly - to take electronic drive, so this might also be your problem if you have one of these versions.

 

Hey thanks Greg for the valuable information. The engine and transmission conversion were done before I got a hold of the car so I do not know what type of speedometer adapter for the transducer was originally on the car. The transmission that was put into it uses the bullet shaped speedometer gear holder vs the larger round holder that I think would allow the transducer to connect to properly. My tail housing will not allow for interchanging of those two types but you did make me think that if I was to get ahold of one of the right angle adapters that then I could probably be able to attach the transducer correctly to that. So thanks for giving me that idea. Anyway, in the meantime yesterday I simply added a couple of small washers inside of the large screw down nut of the transducer to take up the slack and it has allowed the transducer to be attached firmly to the transmission. The only shortcoming I see is that the transducer's actual cable doesn't penetrate into the plastic drive gear quite as far..about 1/8" of an inch shorter. Mine for sure is an electronic speedometer as I have had the dashboard apart to check on it.

 

Try it and see, sounds like the washer packing should do it.

 

The transducer did snug down firmly using two small washers...problem is that the speedometer is still not functioning. So, on problem solved but I need to move on to looking as to why the speedometer doesn't work. I think I'll start with a new ground connected directly to the speedometer ground on the printed circuit board as some have suggested. We'll see.

 

Check that you have 12 volts, ignition on, to the green wire that goes to the two wire loom plug in the harness that the transducer plug connects with. If so, that side of things should be OK. Also check that the other wire has continuity to the instrument binnacle multiplug. This wire sends the signal.
This is correct for my car as a binnacle identifier:

 

That pdf is useful. Thanks!
Jon