Allison 3060 output speed sensor

Covers engines and transmissions
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astrnmrtom
Posts: 167
Joined: Thu Oct 31, 2019 8:49 pm

Allison 3060 output speed sensor

Post by astrnmrtom »

Right after hitting the road to full time I noticed my speedometer was reading 10 mph too slow. Not only that, but the Intellidrive computer would read the correct speed until about 60mph where it would read zero. This was compared to my GPS speed. When I first start off from a stop the speedo takes a while to register, then slowly pulses back and forth a little until stabilizing 10mph too slow. The transmission occasionally shift harshly but is otherwise fine with no error codes. I've read this may be caused by a failing output speed sensor on the transmission. The problem is, I'm on the road a ways from any major city with an Allison dealer. I've looked at online auto parts stores and of course there's no listing for a Safari Motorhome when doing a parts search. Interestingly enough, there are a couple matches that look the same, but I have no way of telling. Knowing the Allison 3060 was used in countless vehicles from medium trucks, to buses and motorhomes, I can't help but believe this is a common part that shouldn't be hard to find if I only knew what to search for. One option I have is to pull it out and take it to a NAPA and see if they can match it.

Does anyone know a cross reference to the part? Or a common vehicle it was used in?

Thanks,
Tom and Pris Masterson, w/ Buddy the 18 year old Siamese cat.
1998 Serengeti 3706
300hp Cat 3126, Allison 3060
900 Watts of Solar
17cf, Fisher & Paykel residential Refrigerator
Dragging four telescopes around the US seeking dark skies.
TDJohn
Posts: 552
Joined: Sun Oct 27, 2019 11:34 pm

Re: Allison 3060 output speed sensor

Post by TDJohn »

Tom,

The only things I can suggest is crawling underneath and getting the Allison model and series number down, and giving Allison a call. I could be wrong, but as far as I can recall, Allison has its own input and output shaft sensors and being that the CAT ECM communicates with the Allison, that is likely were the intellidrive gets it speed info, same for the speedometer. I know, that on the non computerized engines, like my coach has, the speedometer gets its signal from the alternator, and the Allison has its own sensors to control the shifting parameters.

Also, many of the parts for Safaris cross with Ford medium duty trucks and buses, and some Chevy Kodiak buses too, but I don't know how much of help this will be.

Congrats and all the best on your full time adventures. :mrgreen:
John
'95 Serengeti, Cummins C8.3-300
Allison 6spd.
astrnmrtom
Posts: 167
Joined: Thu Oct 31, 2019 8:49 pm

Re: Allison 3060 output speed sensor - solved!

Post by astrnmrtom »

Just thought I'd post an update on my speedometer issue. I did some more troubleshooting and evaluation of my symptoms compared to what is common due to a faulty speed sensor. Other than the speed error, everything else was fine. No Allison error codes, cruise control worked, my Intellidrive showed consistent transmission RPMs, and the odometer/trip meter was working fine. This led me to suspecting the speedometer itself. Last week I pulled it out and opened it up looking for anything that appeared out of the ordinary. All the internal. connections looked good so I gave it a couple drops of light oil and reassembled it but didn't re-glue the bezel. Still no change - 10mph too slow. I noticed it seemed to go through it's normal routine of doing a full sweep when the key was turned on but at the end of the sweep it returned to a spot below 0 on the dial. On a whim, I left the key on, removed the bezel and clear cover, gently pulled the needle off its shaft, and replaced it so that it pointed to 0. Sure enough, it now registers the correct speed. I still have no idea what happened but it works now. It's as if it somehow lost it's zero point. I should have clued in on the issue earlier because the needle always started off below zero after the error showed up.
Tom and Pris Masterson, w/ Buddy the 18 year old Siamese cat.
1998 Serengeti 3706
300hp Cat 3126, Allison 3060
900 Watts of Solar
17cf, Fisher & Paykel residential Refrigerator
Dragging four telescopes around the US seeking dark skies.
Holoholo
Posts: 11
Joined: Mon Oct 28, 2019 4:52 pm

Re: Allison 3060 output speed sensor

Post by Holoholo »

Thanks much for the information. I have the same problem since we bought the RV 2 years ago. Wife noticed as we took our first trip and she followed in Jeep and I was keeping up with traffic, but she kept dropping back. Called and yelled at me for speeding. Ended up driving on a road that had a speed sensor by the school and I was 10-12 over shown gauge. Was NOT a nice conversation while driving for second time in RV.

Troy Townsend
2000 Safari Zanzibar
2018 Jeep Wrangler
Troy Townsend
2000 Safari Zanzibar (since 2018)
3126B
TOAD- 2018 Jeep Wrangler
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