Add OD lockout switch to 18 Seneca

[Mark S]

I want to add the Overdrive lockout switch that Jayco opted not to have installed in my 2018 (M2) Seneca when new. I found an Allison transmission dealer near me that will make the connection as per Matt, the calibration engineer at Allison, but they are not allowed to add the switch inside the cab.

I reached out to Matt, but as someone here stated, he is no longer allowed to interact with the end user. I’m trying to figure out what type of switch to use and what gauge wire to run. The Allison tech will make the connections at the transmission if I run the wires. Seems kind of silly but I guess I understand.

Suggestions?

[Robbbyr]

Originally Posted by Mark S

I want to add the Overdrive lockout switch that Jayco opted not to have installed in my 2018 (M2) Seneca when new. I found an Allison transmission dealer near me that will make the connection as per Matt, the calibration engineer at Allison, but they are not allowed to add the switch inside the cab.

I reached out to Matt, but as someone here stated, he is no longer allowed to interact with the end user. I’m trying to figure out what type of switch to use and what gauge wire to run. The Allison tech will make the connections at the transmission if I run the wires. Seems kind of silly but I guess I understand.

Suggestions?

Mark - My 2014 has the factory-installed switch, I could go to my unit tomorrow and pop off the dash and get the Freightliner part number off of it. I am very experienced at getting into the dash!

But I think my switch works through the vehicle's multiplexed network and talks to transmission control module (TCM). But I'm sure the switch could be made to function even without using the network. And I suspect very light gauge wiring would suffice.

If I can do this to help let me know!

[SloPoke]

Originally Posted by Robbbyr

Mark - My 2014 has the factory-installed switch, I could go to my unit tomorrow and pop off the dash and get the Freightliner part number off of it. I am very experienced at getting into the dash!

But I think my switch works through the vehicle's multiplexed network and talks to transmission control module (TCM). But I'm sure the switch could be made to function even without using the network. And I suspect very light gauge wiring would suffice.

If I can do this to help let me know!

You can... but as Robbbbbbbbbbby sez,(pun intended) our switch is muliplexed. It should go thru the TCM to properly work and the switch is a standard Freightliner switch that plugs into one of the spare connectors behind the dash.

[Mark S]

Ok, guys, after reading this and speaking to Slow Poke I am going to visit my Freightliner dealer and see what they say. Thanks guys.

And Rob, thanks for the offer but Steve had photos available and texted them to me.

Thank you both.

[Bruceter]

This is interesting. Following closely. I have just made a deal on a new early 2018 Seneca but have not yet taken delivery. I too am looking to have a O/D lock switch installed.
I too have reached out to Matt @Allison and was told the same thing, he was told not to deal with the end user.
So from there I went to a Allison dealer/distributer in my area and asked about having the transmission shift mode changed to the performance mode and have the O/D switch installed. Was told doing the shift mode to performance is not a problem but they had never installed a O/D lock out switch. They asked if I could do more research through Jayco as to whether the main wire harness to the TCM already has the wires needed for the switch to operate. Well we all know how it went with Jayco, they told me to go to my dealer for that kind of information. So i skipped my Jayco dealer and went to Freightliner. The first person @ freightliner basically pointed the finger back to Allison. After a bit conversation he reached out to another fellow that said they could probably look into the harness question but I would have to book the unit in and have a mechanic take a wire diagram and compare it as to whats installed in the unit. So it would cost a few bucks just to fine out whether the wire are in the harness. So that’s about as far as I have gotten fo installation of O/D switch.

While I was at Allison I inquired about having a electronic push button shifter installed. That way a person would have the best of both worlds in being able to choose any gear up or down and being able to choose between shift modes all at the push of a button. Allison does not make a electronic shifter for the 2500 so they could not help me that at all.
But I did a little research and found that Arens and Orscheln both make electronic shifters for the Allison 2000 series transmission, as a matter of fact Arens makes all of the electronic shifters for Allison Transmissions. They just have the Allison name on them.
Unfortunately I have yet to locate any retail dealers that deal with either of these companies.

[Mark S]

I went to my local Fort Lauderdale Freightliner service department yesterday and I got speak to the transmission tech who will be doing the addition of the OD lockout switch. He seemed very competent.

The tech was unsure about what switch to use, but lucky for me, the previous night Steve (Slow Poke) sent me a photo of his switch and his VIN number. Sure enough, the tech took a screen shot of the VIN and said he will use the exact set up. Perfect! Thank you Slow Poke.

I bring the Seneca in a week from Tuesday for the work. I will keep you posted.

[Bruceter]

That sounds great for you Mark, please keep us posted on how it works out for you. We purchased the same unit as yours 2018 37TS

Bruce

[MD3]

I am also very interested in this....

I am still on the fence with an aftermarket engine tune to bring up the power levels. I like the idea of the OD switch for towing in the hills.


_

[Dave and Tina Reyburn]

Hi - Can someone tell me what this overdrive lockout switch does? Is it to prevent the transmission from shifting into overdrive?

[Mark S]

Originally Posted by Dave and Tina Reyburn

Hi - Can someone tell me what this overdrive lockout switch does? Is it to prevent the transmission from shifting into overdrive?

Yes, it locks out 6 th gear to make climbing steep grades more pleasant.

2018.5 and newer Seneca’s have the Allison 3000 transmission that has electronic selection of gears. Before 2018.5 has the Allison 2500 and does not have that option.

[RyRoRyan]

Originally Posted by Mark S

Yes, it locks out 6 th gear to make climbing steep grades more pleasant.

2018.5 and newer Seneca’s have the Allison 3000 transmission that has electronic selection of gears. Before 2018.5 has the Allison 2500 and does not have that option.

On the Allison 2500's both 5 and 6 are overdrive gears...the OD will actually keep it in 4th gear giving you a max speed of about 55MPH...just FYI.

[Mark S]

Update on my OD lockout switch:

After sitting in Freightliner’s storage lot for almost 3 weeks, and me calling about every third day, I called yesterday and told the service writer that I was picking up my Seneca today, done or not. Miraculously, they got it into the shop today. I did a drive by and sure enough, it was in the shop with the dash torn apart and they found that they needed another wiring harness in addition to the one they ordered. Hopefully, the part will be overnighted and arrive tomorrow.

Keep in mind that I in brought in an email from Matt Lazier, Allison calibration engineer, (from back when Matt was allowed to interact with end users), stating what needed to be done and SlowPoke’s VIN so they could source the parts.

Today the service writer told me this is “sort of an experiment” for them. This was supposed to be a “not a big deal to do” job.

I am not sure what to think right now. I was actually ok with the transmission reprogram as it was . I thought the OD lockout would be nice, but at this point I hope I made the right to bring decision my Seneca to my Freightliner dealer for this work.

To be continued.

[SloPoke]

Mark,
I'm gonna call you shortly... Tell me that they ran out of empty switch port connections???

and you need this because you have exceeded the 5 switches already??? I'm gonna curse Jayco if that was the underlying reason they cheaped out and did not include the switch in the first place.

Page 17 of the .pdf

[Robbbyr]

While I have been in my dash many times (including earlier today!) I have never taken the time to determine whether my factory-installed OD lockout switch is a SmartPlex networked "Smart" switch or whether it has a dedicated wiring harness leading to the transmission control module. Will be interesting to see how this works out!

[Mark S]

Originally Posted by Robbbyr

While I have been in my dash many times (including earlier today!) I have never taken the time to determine whether my factory-installed OD lockout switch is a SmartPlex networked "Smart" switch or whether it has a dedicated wiring harness leading to the transmission control module. Will be interesting to see how this works out!

I just got off the phone with Steve (Slow Poke) and we think he figured out that the possible reason Jayco eliminated the OD switch is that they saved on the switch expansion unit. Which is probably the part I am waiting on. It seems the switch goes through the entire control system.

Hopefully I will be back tomorrow telling you how wonderful the OD switch works and it was worth the aggravation and money.

[Robbbyr]

My 2014 must have come with the expansion module because when I put my fog lights in I had to identify and utilize one of the unused "Smart" switch connectors. There were three unused ones bundled together in the dash; one connects to my added fog light switch and there are still two unused I tucked back into where they came from.

I guess anything to save a penny these days!

[Bruceter]

So this is interesting, I had my early 2018 Seneca without O/D lock out switch in at my local Allison dealer on Tuesday. I had talked to them earlier about having the transmission reprogrammed to performance mode as well as possibly putting in the O/D switch. They wanted to plug in the unit and confirm which transmission program it had as well as some other info needed for the mode reprogramming and have a look at what was involved in possibly putting in the switch. As a matter of fact they even mentioned if I wanted to they could possibly install another switch to possibly shift between economy mode and performance mode. Which I don’t think is really needed.
Anyways they are going to proceed with getting the new performance program from Allison for me. As for the O/D switch their biggest concern was taking the dash apart and cutting a hole in it. I had mentioned to them that there was possibly a wire harness available from Freightliner but they said it would be just as easy to make one up themselves and probably cheaper than any thing from Freightliner.
So never got a price yet for the switch install because of their uncertainty as to how long to take the dash apart.

So anxious to see how you make out Mark!

Bruce

[Mark S]

Ok, it only took 3 1/2 weeks and $1,340 but I now have an Over Drive lockout switch on my 2018 M2 Seneca. Obviously it is a challenge to test the improvement in mountain climbing here in south Florida but while driving at 60 mph and hitting the button, the RPM goes from 1,600 to 2,600. I’m thinking that will make a difference climbing.

I’ll get to test it in the hills of Tennessee and North Carolina in two weeks.

I still contend that Jayco cheaped out by not having it installed from the Freightliner factory but at least now I have it.

[Robbbyr]

Originally Posted by Mark S

Ok, it only took 3 1/2 weeks and $1,340 but I now have an Over Drive lockout switch on my 2018 M2 Seneca. Obviously it is a challenge to test the improvement in mountain climbing here in south Florida but while driving at 60 mph and hitting the button, the RPM goes from 1,600 to 2,600. I’m thinking that will make a difference climbing.

I’ll get to test it in the hills of Tennessee and North Carolina in two weeks.

I still contend that Jayco cheaped out by not having it installed from the Freightliner factory but at least now I have it.

Yea!

[Mark S]

Originally Posted by Robbbyr

Yea!

Well not so fast. The transmission is what I was hoping for. But now as I turn off the engine I hear an air hissing noise from behind the dash and the front air tank drains to nothing in 10 minutes.

I’ll call them in the morning. It’s actually almost funny. Well, no it’s not. On the bright side I have an OD lockout.