Transmission Temp range

[jacwjames]

When I start the rig it idles at 800 rpm, I don't usually change it. 

[Guest Ray Davis]

51 minutes ago, jacwjames said:

When I start the rig it idles at 800 rpm, I don't usually change it. 

I have an idle speed adj sw on my dash.   I don't know if all Monacos have that or if I'm special.  LOL

It's a rocker momentary type sw and I keep mine down as low as it will go which is about 650 RPM.

800 RPM may be part of the problem

[Ivan K]

My ISM is set to 700 idle, in the ECM. Jumps to 850 with SET button press, only in neutral and park. Release the brake and its down to 700. 

[jacwjames]

I'll see what mine backs down to.  I know it will go higher but not sure what the bottom end is set at. 

[Chuck B 2004 Windsor]

3 hours ago, Dr4Film said:

Chuck B,

This one I have to disagree with you as I trust it in my engine 100% as it performed exactly like the service manager said it. He worked at the truck repair facility where I was towed into in Terrance BC with a small hole in the bottom of my radiator. I have used it twice now with 100% success.

It hasn't caused any effect to the engine in the last 7 years of use but has worked wonders for the radiator.

It even worked for another member here that had a small leak in his dash heat exchanger which is a bear to replace.

Sometime back I think there was a problem with what Cummins calls a wet sleeve cylinder.  I could be wrong.

[Gary 05 AMB DST]

Ironite, does it work on aluminum?

Gary05 AMB DST

[Guest Ray Davis]

1 hour ago, Ivan K said:

My ISM is set to 700 idle, in the ECM. Jumps to 850 with SET button press, only in neutral and park. Release the brake and its down to 700. 

I can use the cruise to jack the idle up too. Hit the set button and the speed really jumps. It will raise the RPM real hi, I use it to build air faster.  The idle sw I mentioned is a sw labeled idle, it won't go very hi, not sure how hi.   I have never thought to ask if others have this same idle switch.

[96 EVO]

3 hours ago, jacwjames said:

When I start the rig it idles at 800 rpm, I don't usually change it. 

Try lowering it to 700 or 725.

Like Ivan mentioned earlier in this thread, a lot of tranny heat is generated during low speed / idling in gear, by the torque converter slipping. The higher the idle speed, the more slipping.

May help, especially with backing into your parking spot.

23 minutes ago, Ray Davis said:

I can use the cruise to jack the idle up too. Hit the set button and the speed really jumps. It will raise the RPM real hi, I use it to build air faster.  The idle sw I mentioned is a sw labeled idle, it won't go very hi, not sure how hi.   I have never thought to ask if others have this same idle switch.

Ray, I have no switch. It's all done with the cruise control buttons while the trans is in neutral.

Edited February 19, 2022 by 96 EVO

[jacwjames]

I know that in my manual there is a warning about not having the rig in reverse for extended periods of time.  I have to back into my garage, most of the time I can do it the first time but if it takes multiple attempts the tranny temp climbs pretty fast. 

[Chuck B 2004 Windsor]

Allison considers their transmission in a motor home Light Duty Use.  Allison also recommends that when shifting from drive to reverse and reverse to drive, by going through neutral.  Drive, neutral, reverse;  from reverse to neutral to drive.  I doubt that many on this group does that.  

[96 EVO]

I've always stopped in neutral for a second while changing directions. Do it in my SUV as well.

[jacwjames]

So I took the rig for a drive, first with the fan off. 

Got the rig to temp and parked in a flat parking lot to check oil level, I added ~3 quarts, I lost about 1 quart pulling and changing one hose off the transmission and then I figured the volume of the new hoses and cooling radiator was about 2 quarts.  Level checked OK

I then turned the fan on and the temp dropped from 147F to ~140F within minutes.  I then drove home with the temp staying at 134F.  Ambient temp outside is ~40F so it's pretty cool so I have to take that into consideration.

The real test was backing the rig into my garage, slightly uphill grade, backing in at an angle so it's fairly slow.  Temps stayed right at 135F and didn't climb, I even pulled forward and backed up slowly a couple times.  Temp stay ~135.   I checked the temp of the Inlet (100F) to the cooling radiator and the outlet (92F) so the system is definitely pulling heat out of the transmission fluid, you can fell it.   I don't have a thermostat control on the tank yet, I was going to use 150F, I'll have to play with it some and see if that is a good temp to kick the fan on, may be too high. 

So adding the cooling stack looks like it will work, not sure if it would be enough by itself or not, I could easily swap hoses and test it but for now I'm satisfied.  May take it on a longer trip into the mountains not too far from me and pull some hard grades.  I need to make sure the rig is at 100% before my wife takes in a trip to the Louisville dog show nest month.

[Ivan K]

Sounds like a good progress, personally, I would go with higher thermostatic setting for the fan, like 180 or so. Normally it would be about the same temp as the engine coolant.

[jacwjames]

9 minutes ago, Ivan K said:

Sounds like a good progress, personally, I would go with higher thermostatic setting for the fan, like 180 or so. Normally it would be about the same temp as the engine coolant.

I'll have to play with it, it's hard to say how it do with a higher ambient temp.  I'll install the 150F and see how that cycles. 

But it's a lot better then watching temp climb to +225F while backing into my garage like it had done before. 

[jacwjames]

22 hours ago, jacwjames said:

When I start the rig it idles at 800 rpm, I don't usually change it. 

So I checked my idle speed today, when I started the rig it was at 800 rpm,

Using the idle control on the dash I was able lower it to 600 rpm. 

[Ivan K]

I am just curious if it stays at lowered idle when you release the park brake and then put it in gear. Mine goes to preset 700 idle as soon as park is released, from where ever I set it manually and I think it makes sense.

[jacwjames]

Yes, it stayed at a lower RPM as I drove, I'll have to check if it reset after I parked. 

I normally don't fool with the idle speed so this is new territory for me.

[Dr4Film]

40 minutes ago, jacwjames said:

So I checked my idle speed today, when I started the rig it was at 800 rpm,

Using the idle control on the dash I was able lower it to 600 rpm. 

Mine is set for about 640-650 rpm. I adjusted it such that when on a medium incline it will hold the coach in one place without having to hold the brake pedal.

[jacwjames]

So I took the rig out on a longer drive and got it on the Interstate with speeds ~75 mph.   The engine was at 180F before I got on the interstate, transmission was ~165F.  The transmission temp climbed to about 178F, this was after about 30 miles and pulling some good grades.  Took it back to the house, at one point the temp got to 181F but that was the max.  I stopped and checked the temps on IN/OUT of the cooler I installed, IN was 135F and OUT was ~124F.  The fan never did run, I had mounted a 150F thermostat on it, this was a surface mount type so it was only seeing ~120F next to the IN port.  So the cooling stack itself is providing ~10F of cooling, maybe more while driving down the road and wind wiping up around it.  The hoses also will provide some cooling affect. 

Got home and as I started backing into the garage the temp was 178F, it did not move, I even pulled forward and backup a couple times.  In the past I would  have been over 215F with the current ambient temps.  Last time I backed into the garage it climbed to +225F, this time it didn't move. 

So I am going to look at getting a better thermostatic control.  May try to find a port fitting. 

The fitting that comes with the fan is a 7/8"-14 o-ring female x -12an male  Does anyone have a source for a fitting or thermostatic controller that would work in the 7/8" oring end???

 

[Ivan K]

You could look into Earl's or Russel Performance catalogs online to pick a part number to search for.

[jacwjames]

I contacted Derale, they do sell fan control on the smaller fans but not on the ones with the 12AN connections, ODD!

I did find a female/male JIC with a 1/8" port for a sensor and I found a sensor the comes on at 140F and off at 125F.  I can also buy a lower temp surface mount switch.

But what I am considering is setting up data logging on my Silverleaf and see what happens on my next trip.  I think if I log both transmission temp and voltage I might be able to see what's going on and if I need to have a different fan switch, the one I have is a surface mount 150F on switch. 

Does anyone use the Data Logging function of Silverleaf VMSpc

 

[Ivan K]

I use screw-in temp senders and digital gauges that are adjustable to trigger a fan (or whatever) at exactly any temp you want. All depends how complicated you want to make it. I also install the senders at the oil pan side, that's where I want to see the temps.

[jacwjames]

59 minutes ago, Ivan K said:

I use screw-in temp senders and digital gauges that are adjustable to trigger a fan (or whatever) at exactly any temp you want. All depends how complicated you want to make it. I also install the senders at the oil pan side, that's where I want to see the temps.

Thanks Ivan, ideally that's probably what I should do, maybe at some point I'll go that route.

For now I'm going to try and set up data logging and see how the rig performs.

My wife has a dog show in Louisville next month, which will give the coach a good workout.  If temps stay good on that trip I'll leave it like it is. 

 

[jacwjames]

So I played with the data logging feature this AM, I used a mouse to be able to better set it up but unless I attach a multiport USB connector can't use the mouse and monitor the engine at the same time since my tablet only has one micro attachment port. I do have a splitter that I will try later.
I was able to get it to recognize and record multiple inputs, they will record every 60 seconds. 

Engine temp
Voltage
transmission temp
Boost

It will record and I can then save them to a note pad file to look at. The transmission temp is the one I am interested in but the others will provide info as to what the engine is doing and possibly if the fan is running both by watching temps and the voltage.  Pulling a long grade I should see higher boost and temps.  If stuck in traffic and have higher temps I should see voltage fluctuate(hopefully).   I could also look at including oil pressure which would be lower stuck in traffic, higher pulling a grade. 

I have decided to replace the fan switch with a 140F switch, ON at 140F and OFF at 120. The temps I saw the other day were good with a temp of 181F but if the temps rise to ~200F the cooling unit should see at least 20F higher at with the lower switch temp it should cut on.

If switch doesn't work as well as I hope I'll change to a port type switch but for now I'll keep it simple. 

[jacwjames]

This is an old post but I thought I'd report the performance of adding my transmission cooler. 

Finally got a chance to take the rig on a longer drive, drove from E TN to Pa yesterday, ~480 miles.  I drove I81 north, which does go through some hilly terrain with decent grades.   My transmission temps stayed at ~165-174F on the  interstate, never saw it climb above 180 on any of the grades.  Previously I would have seen transmission temps above 190 and sometimes up to 200F on the grades. 

When I got off the interstate I got stuck in some stop and go traffic and temps never exceeded 185.  In the past I would have been much higher, probably 220F.  The highest I'd ever seen is when I got stuck in traffic in Tuscon and temps were +230F. 

The data logging worked pretty good, I was able to pull  up the log and see what temps were throughout the trip.  I logged oil temp, volts, transmission temp, and boost.  I was hoping to see if I could tell if the transmission cooler fan was coming on but I did not see any thing to indicate this.  At one time the transmission temp dropped to ~155 out of the blue when I had been running ~175F but not sure if the fan came on or not.  I may try to install an indicator light on the dash. 

So the addition of the cooler has made a significant improvement in temps.   This also pretty much confirms the transmission cooler internal to the CG&J transmission is not sufficient to do the job.