Installing a ZF S-47 Any Ideas for the Speedometer??

[1Turbo10]

I am replacing the old T-19 with a S-47 I am rebuilding. Problem is the ZF has no place for a Speedometer input. I have an 87 2 wd CC Dually and I do not want to loose the speedo!! Any Ideas would be welcome.

 

[justinray]

Gps speedo?
Or change the rear end to one with the VSS

 

[1Turbo10]

Gps speedo is a thought,anyone make an Electronic one that would use magnets ane read driveshaft rotation??

 

[jaluhn83]

The ISSPRO programmable speedos work well off the 10.25 VSS, and IIIRC, they sell a pickup kit to mount on the driveline if you don't have a VSS.

 

[Black dawg]

I am replacing the old T-19 with a S-47 I am rebuilding. Problem is the ZF has no place for a Speedometer input. I have an 87 2 wd CC Dually and I do not want to loose the speedo!! Any Ideas would be welcome.

why not convert the trans to use a speedo while you have it apart?

 

[79jasper]

why not convert the trans to use a speedo while you have it apart?

I "think" the main shaft is different. Won't have the hole for that little locating ball. At least that's how the 1356's t-cases went. But I "think" all 47's should have it. By the time of the 52's, all trucks would be the vss driven in the rear end. Don't quote me though. Been awhile.

 

[1Turbo10]

Yes,main shaft and case will not allow a speedo Gear. I will check out the Ispro set up,Thanks.

 

[Shadetreemechanic]

You could use an s-42 case. Isn't the only advantage to the s-47 the lower first gear, or are there other upgrades worth having in an s-47?

 

[79jasper]

You could use an s-42 case. Isn't the only advantage to the s-47 the lower first gear, or are there other upgrades worth having in an s-47?

50ft/lb torque standability.

 

[The Warden]

50ft/lb torque standability.

Just for general knowledge, does anyone know what ZF changed to make the S5-47 capable of handling more torque safely? I wonder if any changes could be retrofitted into an S5-42?

 

[79jasper]

I don't think so. IIRC the synchronizers are the main change. Stronger material.