SM 420 or Dana 18 Speedometer...anyone have ideas converting dash to use either? (1 Viewer)

[slickrock]

I have the option of using my SM420 tranny or Dana 18 Tcase (out of older jeeps and other?) for a speedometer. I will have to make a custom gauge cluster to accept some OEM cable/speedometer.

Anyone have any suggestions or ideas for what might work well to make a one-off cluster using OEM Speedo cable/gauge from any vehicle that used the SM420 or Dana 18? I looked into electronic gauges but very expensive. I'm more inclined to something I can find at a pick a part. If anyone has seen anything that might look good/ work well, pass it along.

 

[cruiserjunkie]

Can't you get a custom Speedo cable made? Toyota one end Chevy the other

 

[slickrock]

I saw something online about a gps speedo or electronic speedo that uses a sensor placed on the disk brake caliper...anyone know about this?

As for a custom, yes I can have one made but I am trying to cut down on the mix and match parts and one unit that I can custom make sounds more appealing.

 

[Poser]

Dan,



The Dana 18 was last installed into a Jeep vehicle in 1971.

The SM420 was done in 1967.

You want to cut down on mix and match parts in a heavily modified 1974 40 series?

However, you want to try and install a speedometer head unit and cable from a CJ or a Chevy/GMC truck?

Have you looked at just how different those items are compared to a Land Cruiser instrument cluster?




The least expensive component in a speedometer system is the cable.


Figure out your length, remove the speedometer drive from your Dana 18 and bring that and your Toyota cable with you to a speedometer shop in the Fresno area and have a cable made while you wait.

Google speedometer repair; it is amazing the places that come up around that area.






.

 

[hudyhue]

Damn forget a out it... Speed is overrated ( in a 40 anyway!)

 

[msapers]

I run an SM420 in my 76. My stock speedo works fine. It was like that when I bought it but I'd be happy to check on how it was done. I'll take a few photos of the setup in the morning if you like.

 

[Poser]

I run an SM420 in my 76. My stock speedo works fine. It was like that when I bought it but I'd be happy to check on how it was done. I'll take a few photos of the setup in the morning if you like.

The SM420 does not drive the speedometer...That section of the transmission housing is removed when the transfer case adapter is bolted up.


Your transfer case has the speedometer drive in it.

 

[G_Stratton]

I am running an SM420 connected to a Dana18. The stock speedo cable came in about 10 inches to short after everything was installed. I changed everything out for new gauges and used the electroning pickup, removing the cable altogether.

 

[slickrock]

Dan,

The Dana 18 was last installed into a Jeep vehicle in 1971.

The SM420 was done in 1967.

You want to cut down on mix and match parts in a heavily modified 1974 40 series?

However, you want to try and install a speedometer head unit and cable from a CJ or a Chevy/GMC truck?

Have you looked at just how different those items are compared to a Land Cruiser instrument cluster?

.

Steve,

I have looked into GPS speedometers (very cool and speedometer is reasonable price but add in the receiver and it gets into the 300 range unless I can find one that would work with my marine GPS antenna I have). This would be the easiest option. But, I have a Garmin GPS III and a GPS V that I may be able to fabricate some type of recessed gauge cluster mount that would replace my mechanical speedometer. I need to make a few pictures of both the cluster and GPS and see if someone with Photoshop can make a few different pictures of the GPS molded into the cluster before I start chopping.

Electronic units are a bit cheaper and I may be able to find a sender that works off the 40's flywheel or one with a magnetic pickup with sensors on the drive shaft or and I am a bit unclear on this sender, a unit that attaches to the back of my front disk brakes.

Mechanical units are a more reasonable with price and I am waiting to hear back from a few online sources to see if I can track down a sender that bolts into the SM420 that will work with type X speedometer.

Final option is the one I started the post about, finding a stock speedometer out of an older 60s rig that I can take apart and reinstall in my stock gauge cluster. This would take some creative fabrication but I may get lucky in a junk yard and find an old truck that has both the speedometer that can be modified to fit into my stock gauge cluster that already has the right length cable and sender from the tranny. The length is pretty short for the cable and an older truck should have one that would be long enough.

Only problem about the last one, which you bring up, is finding a truck in a pick and pull (very large auto yards in my side of the country) that had an SM420 and has a speedometer that can be modified for my stock uni . I need help in narrowing down what I am looking for with a few suggestions so when I go into the yard, I will be looking for specific trucks / years instead of crawling under everything that looks like it is 50 years old. It would also help if i narrowed my search because I can look up the inventory online instead of driving the hour away and physically search the yard. I also had my spine fused and rods and bolts put into it so the crawling around on a rocky ground with a 2 ton truck over me needs to be as short as possible or I the pain will make it a short trip without any luck finding what I need.

Some research: Installing a Universal Magnetic Pickup Speedometer

Stewart/Warner speedo/senders DeluxeTM Instruments - Stewart Warner

Dan,

The Dana 18 was last installed into a Jeep vehicle in 1971.

The SM420 was done in 1967.

You want to cut down on mix and match parts in a heavily modified 1974 40 series?

However, you want to try and install a speedometer head unit and cable from a CJ or a Chevy/GMC truck?

Have you looked at just how different those items are compared to a Land Cruiser instrument cluster?




The least expensive component in a speedometer system is the cable.


Figure out your length, remove the speedometer drive from your Dana 18 and bring that and your Toyota cable with you to a speedometer shop in the Fresno area and have a cable made while you wait.

Google speedometer repair; it is amazing the places that come up around that area.


.

I forgot to include this option and the easiest. I'm over thinking it but I was planning on redoing the whole cluster with new gauges so I was looking towards something different. I'll make some calls today and post if this is an option locally. If not, I'll get suggestions for shops here to call or email.

Another Mudder also has a Dana 18 and he used the Autometer ATM-1693 and has a speedo gear and cable that bolts right into the Dana 18. He is sending me the part number now. http://www.summitracing.com/parts/ATM-1693/ .

 

[msapers]

The SM420 does not drive the speedometer...That section of the transmission housing is removed when the transfer case adapter is bolted up.


Your transfer case has the speedometer drive in it.

Hmm. I did not know that. That's why I come here, I never stop picking up little tidbits of knowledge. Thank you sir!

 

[slickrock]

Hmm. I did not know that. That's why I come here, I never stop picking up little tidbits of knowledge. Thank you sir!

The 2X4 version does (from my limited experience web surfing) But Poser may prove me wrong. He's good at that.

 

[Poser]

The 2X4 version does (from my limited experience web surfing) But Poser may prove me wrong. He's good at that.

Dan,

How do you have the Dana 18 installed behind this transmission?

 

[jimkyser]

If the Dana model 18 has a stock rear output housing, there is a standard 7/8-18 thread with .104" square drive speedo drive right there. A standard GM speedo cable or any of the many electronic senders that work for a GM application will work there. I have the AutoMeter 5291 Hall Effect sender hooked up to the one in my Willys to drive an AutoMeter 3 1/8" Designer Black Electronic Speedo

It's shown just up and to the right of the rear output flange in this picture from Novak Adapters. (grayish piece going left to right)

 

[slickrock]

Dan,

How do you have the Dana 18 installed behind this transmission?

There is an adapter that the old timer I bought the tranny and case from thinks was an early advance adapters unit. From when I rebuilt them before install, I don't remember seeing any markings on it. I'll see if I can get a good pic from my iPhone. If there are no markings, I'd bet you'd recognize it.

Dan



Edit: AA adapter

What says o h omniscient Poser?

Sent from my iPad communicator

 

[slickrock]

If the Dana model 18 has a stock rear output housing, there is a standard 7/8-18 thread with .104" square drive speedo drive right there. A standard GM speedo cable or any of the many electronic senders that work for a GM application will work there. I have the AutoMeter 5291 Hall Effect sender hooked up to the one in my Willys to drive an AutoMeter 3 1/8" Designer Black Electronic Speedo

It's shown just up and to the right of the rear output flange in this picture from Novak Adapters. (grayish piece going left to right)

Another muddier g_stratton has the same combo. He PMed me a summit part this afternoon. New Vintage USA 99001-04 - New Vintage USA Speedometer Senders

I'm going head first and will redo my entire gauge cluster with autometer gauges so this is the correct route as you suggest.

Sent from my iPad communicator

 

[Poser]

The SM420 does not drive the speedometer...That section of the transmission housing is removed when the transfer case adapter is bolted up.


Your transfer case has the speedometer drive in it.

Hmm. I did not know that. That's why I come here, I never stop picking up little tidbits of knowledge. Thank you sir!

The 2X4 version does (from my limited experience web surfing) But Poser may prove me wrong. He's good at that.

Dan-


The SM420 when used in conjunction with a transfer case adapter loses the speedometer drive provision that came from the factory.


The SM420 used in a factory 4WD application is identical to a factory 2WD application.


A divorced transfer case was used behind the SM420 in any 'factory' 4x4 application.

.

 

[slickrock]

Dan-

The SM420 when used in conjunction with a transfer case adapter loses the speedometer drive provision that came from the factory.

The SM420 used in a factory 4WD application is identical to a factory 2WD application.

A divorced transfer case was used behind the SM420 in any 'factory' 4x4 application.

.

Once again, you givith the knowledge.

Sent from my iPad communicator