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Speedo inop

 My  Dixson speedo failed to run the last trip. Cruise works perfect. Tack works most of the time .
 Checked for ground opens and snugged them, but same result .
  The speedo has , in the past read way high,like 85 at 60 and varied a bit over time .  Now it reads zip as does the odo.  I dont mind the speed data missing as I use my phone/waze for speed, but the miles missing  will force me to buy fuel  more often then needed. 

 Any leads?  Thanks as always. MM
 Yes, it has power and ground .

Re: Speedo inop

Reply #1
Interesting, as mine did the same thing coming home from AZ , didn't stop working just about 15 miles an HR fast at idle it would show 15 mph. As I got close to home it started to work.go figure 🙄
Andy & Eileen
MONTROSE COLORADO
1992 U300  40' 6V92 TA
2016 4 Runner
1998 Jeep Grand cherokee

1998 Jeep Grand Cherokee) Build # 4135 Skp# 122921

Re: Speedo inop

Reply #2
Use a commercial electrical cleaner from auto store or if you see any corrosion on the connectors/wires, use vinegar and table salt combination to make the wires look like new. This is for both ends of the wires.

Ours does the same thing but I've been too lazy to do anything about it. Mileage from the DDEC and the speedo are getting further apart.

Pierce
Pierce and Gaylie Stewart
'93 U300/36 WTBI
Detroit 6V-92TA Jake
1140 watts on the roof
SBFD (ret)

Re: Speedo inop

Reply #3
Mike, my '81 used the alternator for the tach and had a electrical gear driven sending unit in the Allison. Is yours set up the same way?
1999 40 ft. U-320 wtfe build 5563 Chuck & Lynda's "Rollin' Inn"  2030 watts solar
prev. mh's 71 GMC 5 yrs. 73 Pace Setter 1 yr. 78 Vogue 5 yrs 81 FTX 40ft all electric 18 yrs. 1996 Monaco Signature 3 yrs.
2014 Grand Cherokee Overland
Dream as if you will live forever. Live as if you will die today.  James Dean

Re: Speedo inop

Reply #4
My trans has 2 drive boxes on it. Assume that one drives the speedo and one drives cruise.  No idea if that is fact  .
 I have no idea where the rpm signal comes from .


found this ;GPS Speedometer, 3-3/8"/86mm,120 MPH,LED light,black/chrome,001-SP-BC/GPS | eBay

Re: Speedo inop

Reply #5
Belay this post. Didn't notice that the OP has a different speedo than I.
jor

A new speedometer is not expensive. I bought one in 2016 for $109 from Lauderdale Speedometer. Jay will set the odometer to match your actual miles. You just have to calibrate it after installation. Instructions are included with the speedo. (lauterdale)
jor
93 225
95 300
97 270
99 320

Re: Speedo inop

Reply #6
Check out a GPS sender.  I put one in my '92 and it works fantastic.  I have a VDO speedometer.  This is assuming its your drive unit on your tranny that's the problem.  The cruise comes off same drive, straight out and speedo comes of the "tee".  Lauderdale Speedometer is a good source for info.  Ask for Jay.

jk
Jack and Cathy
1992 U280 Unihome 36' Build #4034
Cummins 8.3 /  Allison MT647/ PacBrake
Apopka, FL / Barre Center, NY

Re: Speedo inop

Reply #7
Thanks Jack.  I'll pull the 90 degree drive and take a peek .
  The grease fitting is a little dry.  I dont have the itty bitty 90 degree greaser thing yet. 

 Wait. Are you saying that the GPS replaces the drive and uses the same speedo?

Re: Speedo inop

Reply #8
Thanks Jack.  I'll pull the 90 degree drive and take a peek .
  The grease fitting is a little dry.  I dont have the itty bitty 90 degree greaser thing yet. 

 Wait. Are you saying that the GPS replaces the drive and uses the same speedo?

That's an affirmative. 

jk
Jack and Cathy
1992 U280 Unihome 36' Build #4034
Cummins 8.3 /  Allison MT647/ PacBrake
Apopka, FL / Barre Center, NY

Re: Speedo inop

Reply #9
Here are some pics the drive unit on transmission.  The "silver" colored fitting is for the speedo.  The cruise input comes off the end under the big cap.  Others are my VDO speedo.

jk

Jack and Cathy
1992 U280 Unihome 36' Build #4034
Cummins 8.3 /  Allison MT647/ PacBrake
Apopka, FL / Barre Center, NY

Re: Speedo inop

Reply #10
My VDO speedometer failed intermittently. Bought a new one. Problem fixed.
1997 U270 34FT Build 5140 Cummins 8.3 Allison 3060R
Solar 1920Watts, 14KWH lithium. Orion BMS.

Re: Speedo inop

Reply #11
I had issues with my VDO speedometer a few years ago. The needle was bouncing all over the place. I ordered a replacement. When I started the replacement job I noticed the cable on the speedo end was loose. I tightened it, problem solved. Now I have an extra, just in case.
1993 U300 40ft GV SE
Build # 4344

Re: Speedo inop

Reply #12
No cable on my Dixon. When I greased the sender , water dripped out the end    .
 I ordered the eBay GPS speedo for 70$