Tremec speedometer adapter?

CSCHWER · #1 (**permalink**) 09-22-2007, 09:07 AM

I've put a diaper on my Smith's speedometer! The transmission is pumping fluid up the speedo cable. Does anyone know of a 1:1 or 1:1 reversing adapter that will fit in a TKO 600 and isolate the fluid from the cable? I would rather have it at the transmission rather than in-line with 2 cables.

Chet

Velox · #2 (**permalink**) 09-22-2007, 11:00 AM

Chet, I don't have an answer for your adapter question, but do recall a discussion on this on SCOF a while ago. The consensus was that the cable should not wick trans oil up to the speedo. The usual fault is a missing O-ring or a reverse wound speedo cable. There is supposed to be an O-ring inside the screw-on collar where it goes on the transmission, and that O-ring is needed to keep trans oil out of the cable assembly. Another problem is that some replacement cables are wound the wrong direction which can cause the wicking of oil. Compare the spiral of a new cable and the old cable. Most people with these leaks solved the problem by replacing or installing the O-ring, removing and wiping down the cable, and in some cases, replacing the cable with one that is wound correctly to not allow wicking up to the speedo. Do a search on SCOF and there are probably more threads on this, I'll try and check too, good luck, hope you get the leak fixed

CSCHWER · #3 (**permalink**) 09-22-2007, 04:05 PM

Don,
The screw on collar is on the speedometer on my cable(s). The Tremec uses a Ford cable that has two "O" rings on the push in fitting. I'm thinking maybe the Ford cable I'm using is for the LH not the RH side?
Chet

Velox · #4 (**permalink**) 09-22-2007, 04:38 PM

That may be the case Chet. I know some have had this problem and when the cable was removed and compared to other cables, some were wound right hand, some left hand. Whatever one you have, if you could find same length Ford cables at a parts store and compare the cables, hopefully you could find one that is wound opposite the one you have in now, and try that, see if it doesn't stop the wicking of the trans oil up the cable. Another idea is what you mentioned about an adapter which would isolate oil from the cable, and I found one here http://www.tristatemotorsports.com/D...ct.cfm?ID=8150 that you can review. I'll read up through the archives on SCOF and see if there are other listed solutions.

Lowell W · #5 (**permalink**) 09-22-2007, 06:47 PM

The adapter in the link above is similar to the one on your car now, except that this one looks to be more robust.

I've been thinking about this situation for a long time, since the "jumping speedo needle" phenomenon is also directly related to the cable making a 90° bend coming out of the tranny and another 90° bend under the dash to go into the speedo. If nobody else does it first and no other big Cobra projects rear their ugly heads by this winter, I think I may try to use one of these adapters to reverse the cable direction at the transmission. It would be great if someone ELSE would do it first though, and post details on CC!

Lowell

Velox · #6 (**permalink**) 09-22-2007, 08:17 PM

Well there is another solution which I considered at one point as I had prior speedo problems as well (ended up replacing the entire speedo) and that would be an electronic speedo - gaugeguys have one listed on their classic Smiths cobra gauges page http://www.gaugeguys.com/Smiths/Authentic/cobra.htm which would mean seal off the mechanical connection port on the Tremec - no more leaks! But with a new speedo, new cable, no more leaks and no jumping speedo needle

for now I'm gonna stay with my mechanical gauge. I did change to Smiths voltmeter and electronic oil pressure gauges for other reasons, and they are working great

Blas · #7 (**permalink**) 09-22-2007, 08:59 PM

Disconnect the speedo cable and 90 degree gear drive from the speedo and each other. Then cut about 3/16" off the end of the cable and carefully deburred the end. After reassembly the cable head will now screw all the way onto the gearbox and not wobble. Take the car out for a test and what do you know - a rock solid speedo needle. NO MORE WOBBLE...

Lowell W · #8 (**permalink**) 09-23-2007, 07:47 AM

Quote:

Disconnect the speedo cable and 90 degree gear drive from the speedo and each other. Then cut about 3/16" off the end of the cable and carefully deburred the end. After reassembly the cable head will now screw all the way onto the gearbox and not wobble. Take the car out for a test and what do you know - a rock solid speedo needle. NO MORE WOBBLE...

Great idea, Blas; I had it myself! I also tried lubing the cable (worked for awhile), rerouting the cable (ditto), putting a spacer between the connector and the adapter on the speedo (ditto) AND chopping a little off the end of the cable. They all worked for me for awhile, but the jumping needle returned. I know there's a slight kink in the cable, which is the major culprit, but I really think the additional 180° of bending of the cable, especially in two tight radius bends, is a major factor.

Lowell

CSCHWER · #9 (**permalink**) 09-23-2007, 11:00 AM

I'm trying a 60 inch NAPA # 615-1644 speedo cable right now. It is wound opposite the first one I tried. I'll run it for a while and see. It will probably be OK with the new grease in the cable. I'll try a couple hours of 70 MPH driving and see what happens. Right now the speedo needle is about as steady as the tach. This cable I'm running now seems to fit better. ie the length of the drive cable matches the housing better. When the speedo end is seated, the cable just sticks out enough to engage the gear on the tranny.

Chet

CSCHWER · #10 (**permalink**) 09-23-2007, 05:48 PM

And one other thing. Make sure the teeth on the speedo gear matches the tranny. My transmission came with a 21 tooth that had a wierd tooth shape and caused the speedo to jump.