TH400 speedo gear fix

[Joe Pagnotta CLC19114]

The speedo needle and odometer are no longer rolling on my 76 CDV, so I figured Id ask if there are any TH400 gurus out here...

Im suspecting the internal gear assembly in the trans is broken as the cables and connectors to the speedo head look OK. Can I remove/take apart the gear assembly w/o dumping tranny fluid or is this going to be a bloody mess? Per the FSM for this car, I know the tranny does NOT have to come out to do the repair (hooray for engineers who think about the small stuff!), but I just want a little more insight here...

Thanks in advance

Joe

[Lynn 10923]

You will need to have a pan handy when you pop the speedometer gear housing out. If the trans has the correct amount of fluid in it, you will dump about a quart.

Lynn

[Joe P]

[Bruce Reynolds # 18992]

Joe,

You say that the cables look okay, but, have you actually pulled out the inners to see if they are in one piece?

Have you removed the cable at the Transmission to see if that is the problem?

And, what, if anything, was the speedo needle doing prior to not working?   Was it flickering, or reading nice and steady?

And, if you are under the car, with the cable disconnected, and turning the cable by hand, that is, flicking it around, have someone inside the car to observe the needle or odometer.   If it is moving, then the problem is in the transmission.

Bruce,
The Tassie Devil(le),
60 CDV

[Joe P]

Bruce,

Thanks for the addl info... the needle was rock steady and never flickered. One minute it was working fine, I looked down a minute later and she was at Zero.  I havent gone underneath the car yet, just wanted to collect some info before doing a complete diagnosis.  I will check the inner cable per your advice...

I once had a similar (and truly funny) situation years ago on a 73 Nova.  The needle actually FELL OFF the spindle going over a fine New York City pothole!  Dismantled the entire cluster, reset and glued the needle back on and all was good...

jp

[Joe P]

Bruce (Tassie),

You were on the $ as the cable from the tranny to the cruise control module snapped, new part on order, super easy fix and no fluid dump hassles (eh, but I did change the oil while I was under there!)...

jp

[Bruce Reynolds # 18992]

Joe,

Good to see that the problem was solved without having to perform too much of an operation.

It is very rare for the "inside transmission" parts to break down.

Bruce,
The Tassie Devil(le),
60 CDV