Trans retarder

Topic: Trans retarder (Read 1518 times) previous topic - next topic

Trans retarder

October 10, 2016, 03:42:46 pm

For folks with VPMS, I notice the trans temp displayed on the VPMS doesn't cool down as quickly as the dash gauge. I'm wondering if it being read from 2 different sensors.

Re: Trans retarder

Reply #1 – October 10, 2016, 03:44:49 pm

Bruce,

At least according to Allison there is no "here is where the transmission temperature sender should be located. Can be in sump, line from torque converter or on either side of the transmission cooler. Different readings from each.

Re: Trans retarder

Reply #2 – October 10, 2016, 07:58:59 pm

Bruce, VMSpc can display both the transmission temperature and the retarder temperature as reported on the data bus. The retarder temp will go up quickly and then take some time to cool off. It is pretty typical (on ipy coach) to see the transmission temp run 5-10 degrees warmer than the coolant and the retarder temp to be about the same as transmission temp or jus a couple degrees warmer (about 185°). Retarder temps can quickly go to 225 or more when the retarder is activated and then several minutes to cool off.

Re: Trans retarder

Reply #3 – October 10, 2016, 08:36:29 pm

My 97 cannot easily show both trans temps. Later years can

Re: Trans retarder

Reply #4 – October 10, 2016, 09:08:27 pm

Thanks Brett, I'm clearly reading a different sensor on the VPMS.

Roger I'm reading "trans temp" I'll have to look I don't recall a retarder temp in the guages menu. I am running version 2.5-10.

Re: Trans retarder

Reply #5 – October 11, 2016, 02:52:12 pm

VMS is reading Allison computer which has access to internal sensors. Dash tranny gauge is probably reading the temp of fluid returning from tranny cooler after the heat has been removed. The dash gauge sender is probably on the elbow of the large hoses connected to the tranny cooler. Relocating this sender to the other large hose going to the cooler will allow the dash gauge to show much higher temps.

Re: Trans retarder

Reply #6 – October 11, 2016, 04:40:56 pm

When I explored getting both transmission temp and the retarder temp (which I would like to have), I found a PID number in the VMSpc documentation. However, trying the PID suggested, alas, no results.

Roger, you know our coach/engine: 1999 Cummins M11. Are others of our year getting transmission retarder temps, as well as the straight transmission temp?

Thanks!

Re: Trans retarder

Reply #7 – October 11, 2016, 06:00:12 pm

Someone reported getting into the wire bundling and dug out a retarder temp output or availability with the help of the VPMS guys.

That's as much as I know. If you figure it out please report how?

As a foretravel manager long ago I as the factory did would not hook up a quick moving anything gauge.

Every owner would call and ask what's wrong. Trust me on this.

Re: Trans retarder

Reply #8 – October 11, 2016, 09:39:22 pm

Quote from: Caflashbob – October 11, 2016, 06:00:12 pm

As a foretravel manager long ago I as the factory did would not hook up a quick moving anything gauge.

Every owner would call and ask what's wrong. Trust me on this.

Including the speedometer and tachometer, which probably was the #1 complaint. But spikes in retarder temps are expected but what is the upper threshold values before you start backing off its use. I realize that it's not so much the outgoing temps but the return temps of the fluids.

Re: Trans retarder

Reply #9 – October 11, 2016, 10:08:14 pm

Duh I think I just answered my own? Assuming a 15 lb radiator cap I am guessing 250 F. Before you start to get localized boiling in the tranny cooler section of the radiator unless the retarders get a pre cooler.

Re: Trans retarder

Reply #10 – October 11, 2016, 10:11:12 pm

My tested level is the 250 where the trans buzzer comes on. Load shedding is 300 as far as I remember.

250 is fairly low versus what the trans oil will take. Hence the 300 before the unit sheds load.

My garbage truck fleet owners regularly ran 250 or over trans temps every day. 160 trucks.

My old non transsynd info was 300 for an hour to burn trans oil and turn it orange and smell burned.

I back off at 235 on engine temps. Hard to get the motor past that IMO. 265 is boil over

Re: Trans retarder

Reply #11 – October 14, 2016, 10:23:40 am

It seems to me that the only useful temp would be the fluid after it exits the cooler. What's happening inside the trans might be interesting, but what's the point....kind of like having a wristpin temperature reading. Knowing the fluid temp allows you to react accordingly and adjust speed, gear, service brakes etc.

Re: Trans retarder

Reply #12 – October 14, 2016, 10:48:31 am

Quote from: Chuck Pearson – October 14, 2016, 10:23:40 am

It seems to me that the only useful temp would be the fluid after it exits the cooler. What's happening inside the trans might be interesting, but what's the point....kind of like having a wristpin temperature reading. Knowing the fluid temp allows you to react accordingly and adjust speed, gear, service brakes etc.

Wouldn't it be better to read the temp going out of the trans in order to know the max temp the fluid is? Then take necessary steps to lower if too high.

Re: Trans retarder

Reply #13 – October 14, 2016, 11:07:18 am

Quote from: craneman – October 14, 2016, 10:48:31 am

Wouldn't it be better to read the temp going out of the trans in order to know the max temp the fluid is? Then take necessary steps to lower if too high.

I see your point, but feel like if the cooling system is able to handle the load that it really doesn't matter what the max temp was prior to cooling. Essentially, the data are reflecting the performance of the total system when you read the output from the cooler.

Re: Trans retarder

Reply #14 – October 14, 2016, 12:25:56 pm

If transmission over temp is what is to be avoided, whatever that temp may be, then the fluid temp as it leaves the transmission should be monitored if the internal temp can't be.
Ours hit the 250/275 mark several times on a recent trip with long steep downgrades. Never let it stay that high over a minute or two though.
No alarms. ......

Re: Trans retarder

Reply #15 – October 14, 2016, 12:40:31 pm

Quote from: LookingWest – October 11, 2016, 04:40:56 pm

When I explored getting both transmission temp and the retarder temp (which I would like to have), I found a PID number in the VMSpc documentation. However, trying the PID suggested, alas, no results.

Roger, you know our coach/engine: 1999 Cummins M11. Are others of our year getting transmission retarder temps, as well as the straight transmission temp?

Thanks!

My understanding is that the data bus has about 250 data channels. Retarder temp is reported on PID (channel) 120 as I recall. In VMSpc you can use the PID sniffer function to see which channels are actually reporting data. If PID 120, for example, is not shown then there is no data available. The 1999 may not have a retarder temp sensor and therefore nothing is reported.

Somewhere in that time frame (99-01) FT began using the ISM11. The original (1994) Cummins M11 became the electronic CELECT and then the CELECT Plus with electronic fuel system injectors. The M11 CELECT Plus became the ISM when Cummins applied its Interact System (hence the "IS" in ISM) to the M11 CELECT Plus in 1998. The Allison transmissions added more electronics as well. So sometimes figuring out just what you can get takes some snooping around.

The specs for the 1999 U320 say M11 CELECT Plus . The 2000 U320 is the ISM11. The transmission spec is the same for 1999-2001.

Re: Trans retarder

Reply #16 – October 14, 2016, 01:13:11 pm

Quote from: LookingWest – October 11, 2016, 04:40:56 pm

When I explored getting both transmission temp and the retarder temp (which I would like to have), I found a PID number in the VMSpc documentation. However, trying the PID suggested, alas, no results.

Roger, you know our coach/engine: 1999 Cummins M11. Are others of our year getting transmission retarder temps, as well as the straight transmission temp?

I don't know exactly where the transmission temperature sensors are located on our 1995 U320, and I don't know why it is configured as it is, but I don't think things have been modified from the way it was originally built. That being said, our dash gauge appears to read the retarder output temperature, since it rises very quickly with retarder application (and the warning light comes on when it gets high--probably around 250F). However, the VMSpc appears to read the transmission sump temperature, and it rises very slowly with retarder application. I'm really thankful that both temperatures are displayed!

Re: Trans retarder

Reply #17 – October 14, 2016, 02:59:30 pm

Maybe not relevant, but on our 99' U270, the VMSPC definitely reports the retarder temperature with the Allison MD3060R. I don't remember the PID number but there are quite a few threads which have some detail on setting up a VMSPC gauge for retarder temperature. I rely on that when using it heavily.
Don

Quote from: Roger & Susan in Home2 – October 14, 2016, 12:40:31 pm

My understanding is that the data bus has about 250 data channels. Retarder temp is reported on PID (channel) 120 as I recall. In VMSpc you can use the PID sniffer function to see which channels are actually reporting data. If PID 120, for example, is not shown then there is no data available. The 1999 may not have a retarder temp sensor and therefore nothing is reported.

Re: Trans retarder

Reply #18 – October 14, 2016, 03:53:19 pm

On my 96 the sensor is on the elbow on the output of the trans fluid,it gets the hottest temps.and yes does cool down fast.

Re: Trans retarder

Reply #19 – October 14, 2016, 03:57:31 pm

Don, if you are getting both then that is great. There are PIDs for Retarder Status and Retarder % engaged as well and they don't work on my coach. There are many specific details about each coach that are hard to access at a distance. I have been adding a remote access to my kits so when this comes up I can be there in person (sort of) to lend a hand. It has come in very handy on three systems so far. And as different as FT are from one year and model to the next they are different in the same year as well I even have one of my kits on an American Eagle. That was really challenging. So I have to make best guesses some times and then help the end user work through what is possible. There is a standard gauge for coolant level. I haven't found a FT yet where that works.

I have a pretty small (1) sample set nearby to try things out on so I rely on reports from the field. Your input is helpful. Thanks.

Re: Trans retarder

Reply #20 – October 14, 2016, 08:10:21 pm

I too have the Retarder and Tranny temps (both) and I think Dave K put the retarder one on my screen for me when in Q 2 yrs ago. I too would not be without it. He also put the % throttle position as well and although it does not really have to be there I like to see what I am at even though I get --load/Boost/turbo/temp etc as a moving graph as well as separate gauges.
JohnH

Re: Trans retarder

Reply #21 – October 16, 2016, 02:19:38 am

As John and Don have reported, at least on 99 Allison 3060 and later, retarder temp PID is active and reported, although you have to sniff it and add it. On ours, the reported temp was much lower than actual, and I needed to add a correction factor to make the reading similar to the trans temperature when the retarder was off. I'll look at our VMSpc tomorrow and report what the factor I used.

I never looked for the % retarder engaged PID, so don't know if it works for our year, but that would be useful also.

Re: Trans retarder

Reply #22 – October 16, 2016, 10:46:58 pm

Just checked my VMSpc, and since the latest VMSpc update (and my going to WIN 10), it seems that the correction factor of 1 (none) is working fine, so my previous correction factor isn't needed any more.

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