I acquired a v8 conversion 1984 XJS from my father that was never quite finished. I am slowly getting it finished and turning it into a fun daily driver. The speedometer does not work. I pulled it out some from the dash enough to discover that it is an electronic one that does not use an actual cable from the transmission to the speedometer. I crawled under the car and discovered that on the tailhousing of the Chevy Turbo350 transmission that there is nothing screwed onto the fitting where a cable or transducer should be at. There are 2 wires close by not connected to anything. There is transmission fluid seating out of the hole. There are no magnetic type sensors on the rear of the driveshaft either.

Can you tell me which transducer I will need to make my speedometer work properly? Is it a simple OEM Jaguar transducer or do I need some sort of special one made for the conversion?

Thank you for your help!

 

Google "Jaguar DAC4569"



That's the transducer that would be appropriate for an '84.

The speedometer circuit doesn't know what engine you have so it should work OK....unless there have been other changes we don't know about. The threads on the existing fitting on the transmission "should" match up to the transducer as that's something that, as far as I recall, was not Jaguar-unique.

Cheers
DD

 

I agree with Doug, although the original transmission was a Jaguar version of the TH400, I don't know if the threads were different between the 350 and 400.

 

Ok, thanks for the help. Do you know if there is any sort of speedometer gear inside of the tail housing that needs to be changed for the conversion? Seems like I remember reading something like that but I'm not sure???

 

The TH400 has a drive gear which can be had in different versions depending on rear axle ratio and tire rolling diameter. I'm assuming the TH350 is similar. They are color codes to corresond to the particular ratio. Here's a video on the TH400 gears. You can check YouTube for TH350 videos.

 

Part 9 in the diagram is the output shaft gear, there would be another in the transducer assembly. The speedo and cruise is expecting to see 8,000 pulses per mile.
https://parts.jaguarlandroverclassic.../brand/jaguar/

 

Photo of the speedo gear:


The coloured plastic gears are what you need. They just pull out of the transducer hole. Each colour is a different ratio. The cast ally part should be in your gearbox and the plastic gear runs in that. The steel gear ring you see in the photo is mounted on the gearbox output shaft and should be in your box already. If not it is a tailshaft off job to put on on. As Jagboi said, 8000 ppm is what the transducer must use. There are aftermarket ones, but using a Jaguar one is easiest, obviously. You will find a plug on it that fits into the loom plug you have found in the area. One wire carries a constant 12v, the other the signal to the speedo.