727 Transmission Speedometer Sending Unit
 

I did a search in the MoparForum archives and didn't find any posts relating to this topic, so either I did an absolutely lousy job at searching or I'm the first knucklehead with this issue.

I noticed my interior speedometer gauge which is original to the car not working last trip out and then after pulling into the garage I took a look underneath the car. I noticed a small leak that appeared to be coming from the speedometer sending unit that does into the transmission.

I'm not sure if the unit is broken or just leaking and needs to be tightened and therefore not functioning. I believe the sending unit is original to the car, so perhaps I could just purchase a new sending unit and install it. If I went the latter route, where can I purchase a sending unit for a '69 727 and would that require removing the dash? And or what steps might be involved? Would other material purchases be required (domino effect) if I replace the speedometer sending unit?

Thanks in advance.

inri -

The older 727 "speedo sending unit" is just a set of gears. There's a guy on ebay that has a store that sells the gears for various combinations of rear end gear ratio, tire size, etc.

A google search for 727 speedometer gear should come up with the same guy or similar.

The leak may be due to the housing or seal.

Archer

Thanks Archer!

I'll see about finding this person and inquire about the steps involved in replacing this unit.

You need a big O ring and the small seal for the gear shaft Put some silicon gasket sealer on the O ring when re installing. THE gear seldom goes bad. It is usually changed to correct speedo reading/ gear change. IT is common for it to leak .
Your speedo not working ? Check the cable first ! it may have come loose from the speedo

Since my old speedometer cable got melted on a header I removed it and ordered a new one.
Yesterday I received my oem mopar speedometer cable and today I was going to install it... ...but upon trying to screw the speedometer cable nut onto the transmission speedometer gear housing (big bolt) I noticed that the first 3 or 4 threads on the housing were stripped down to the point that I could not get the speedometer nut on because it would constantly slide off. When I removed the old speedometer cable I did notice that it was loose from the housing but I didn't give it anymore thought because the cable was severely melted and couldn't be used. I forced the new cable pretty hard on the housing bolt to try to grab the 5th thread but I just couldn't get it on.

Seeing how I now need a new speedometer gear housing, when I remove this item will transmission fluid leak out? Is a special tool needed to remove this piece? And will this "domino" into me potentially needing another item?

I can't buy a break today!

[pact] may have a replacement

you may loose a 1/4 cup just have a drain pan under it. Depends also if you jack it from the rear or front. You may need to wiggle it or even use pliers to twist it out. IT'S a 15 minute repair

TvLynn,

I lost about a quart!! I had the car jacked up on the front side as I've been tackling ball joints and rubber brake hoses! LOL. But it came out real easy. The speedometer pinion looks to be in pretty good shape too as only two of the teeth (41 tooth) seem to be a bit different from the other teeth. They're still in good shape but a bit smaller than the rest.

Just waiting for the new speedometer adapter with seals and o ring to arrive!

All RIGHT!!!

I have a working speedometer now!!!

Can anyone tell me where I can add some transmission fluid in the 727? I lost about a quart of fluid when I removed the speedometer housing.

Should I place a funnel and pour a quart of fluid down the dipstick shaft?

Yes the dipstick is also the fill tube