Retarder Temperature Rising, but retarder set to Off

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Retarder Temperature Rising, but retarder set to Off

July 17, 2017, 02:05:31 pm

We just left Glacier Natl Park and I noticed the retarder temp on the VMSPC is rising to 280 degrees with the retarder on. I shut the retarder off (button off, joystick off) yet it got as high as 280 degrees. Various driving speeds would raise or lower the temp, mostly it would rise.

I stopped, performed the test on the transmission by pressing the up and down arrows and got a "79" code. The oil level was "OK"
The retarder temps took about 10-15 minutes sitting at idle to fall to 180 degrees. Afraid to leave city and get stuck.

Any ideas

PS. looking for Allison dealer in Kalispell Mt

Ed

Re: Retarder Temperature Rising, but retarder set to Off

Reply #1 – July 17, 2017, 02:26:05 pm

Ed,

Does the transmission temperature rise only when you are off the throttle?

Is engine coolant temperature steady at normal reading or does it also vary?

Re: Retarder Temperature Rising, but retarder set to Off

Reply #2 – July 17, 2017, 02:44:21 pm

Thanks for replying Brett

No, tranny temp rises to about the 220's up from 180. This is when driving on city streets. Light throttle
Engine coolant temp stays fairly constant.

Retarder temps only begin to lower when stopped at idle. Took about 10-15 minutes

Re: Retarder Temperature Rising, but retarder set to Off

Reply #3 – July 17, 2017, 02:50:29 pm

I had that happen and I needed a new radiator and transmission cooler. The radiator was really much worse off but it did now show the temp increase first. The transmission showed the rise and took a long time to come down. I would look at both of them and see if you can see which one it is.

Re: Retarder Temperature Rising, but retarder set to Off

Reply #4 – July 17, 2017, 02:54:28 pm

So, this happens even when on the throttle? For example, if driving at 20-30 MPH steady throttle the transmission temperature is still high?

Any loss of acceleration, feeling of dragging or other symptom of the retarder being on when it should not be?

Re: Retarder Temperature Rising, but retarder set to Off

Reply #5 – July 17, 2017, 02:55:13 pm

thanks john

Trying to find a shop here in Kalispell, Mt. No luck yet.

Re: Retarder Temperature Rising, but retarder set to Off

Reply #6 – July 17, 2017, 02:58:45 pm

Quote from: wolfe10 – July 17, 2017, 02:54:28 pm

So, this happens even when on the throttle? For example, if driving at 20-30 MPH steady throttle the transmission temperature is still high?

Any loss of acceleration, feeling of dragging or other symptom of the retarder being on when it should not be?

Yes, 3rd gear, 1300 - 1400 rpm.
No lugging, I even checked the jeep to make sure it was set up for towing correctly.

Also, I just drove maybe 300-400 feet in parking lot. I doubt if I even got into second gear. Retarder temp went from a resting 178 degrees to instantly rising to 194.

Re: Retarder Temperature Rising, but retarder set to Off

Reply #7 – July 17, 2017, 03:09:02 pm

Malfunctioning temperature sender/sensor?

Re: Retarder Temperature Rising, but retarder set to Off

Reply #8 – July 17, 2017, 03:22:46 pm

If no sensor or ground problem, it might be a stuck retarder actuator. I would want to get it looked at right away. Hopefully something external. How about a call to an Allison shop?

Pierce

Re: Retarder Temperature Rising, but retarder set to Off

Reply #9 – July 17, 2017, 03:26:14 pm

Ed,
Hope this can help till while you continue to search for a service center. Allison Troubleshooting Guide.
John M

http://ww2.justanswer.com/uploads/HE/HeavyEquipmentTech/2013-09-22_223029_allison_transmission_md3060_trouble-shooting.pdf

Re: Retarder Temperature Rising, but retarder set to Off

Reply #10 – July 17, 2017, 03:40:33 pm

A shop with a Pro-Link 9000 and a Allison World Transmission cartridge may help diagnose the problem. A truck shop may have one if no Allison dealer close by. http://aepsurplus.com/custom/auctionArchiveDetail.cfm?aID=1198

Fault code 79 is "sump temperature too high."

Pierce

Re: Retarder Temperature Rising, but retarder set to Off

Reply #11 – July 17, 2017, 03:47:29 pm

You might try calling Sam Clemmons at Western States Transmissions. They have an excellent Allison troubleshooting website.

Re: Retarder Temperature Rising, but retarder set to Off

Reply #12 – July 17, 2017, 03:54:20 pm

Quote from: Pierce & Gaylie Stewart – July 17, 2017, 03:22:46 pm

If no sensor or ground problem, it might be a stuck retarder actuator. I would want to get it looked at right away. Hopefully something external. How about a call to an Allison shop?

Pierce

I was wondering that also, but if it was stuck would the retarder be in the "on" position? I don't feel as if it is on.

Re: Retarder Temperature Rising, but retarder set to Off

Reply #13 – July 17, 2017, 04:48:43 pm

At this point, I'm guess (yes, guessing) that it's a bad connection to the sensor or a bad sensor. The retarder temp sensor is located just above the retarder solenoid. The tranny sump temp sensor may be in one of the transmissions lines or screwed into the sump. The Allison parts drawings don't show a sump temp sensor, only a retarder temp sensor. Other forums point to a sensor failure and also say the coach manufacture may have put the temp sensor location convenient to them.

Attachment below shows an Allison temp sensor. Yours may or may not look like this one.

Pierce

Re: Retarder Temperature Rising, but retarder set to Off

Reply #14 – July 17, 2017, 07:40:50 pm

Quote from: Lance Camper

Retarder temps only begin to lower when stopped at idle. Took about 10-15 minutes
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If I were trying to cool things down, I would put it in park and run it at least at 1/2 throttle if not full throttle.

Re: Retarder Temperature Rising, but retarder set to Off

Reply #15 – July 17, 2017, 09:17:59 pm

Quote from: Dave Larsen – July 17, 2017, 07:40:50 pm

If I were trying to cool things down, I would put it in park and run it at least at 1/2 throttle if not full throttle.

I would sure not recommend that. Perhaps 1,100 to 1,200 RPM, which would take very little throttle in neutral.

Can't see recommending "governed redline" which is exactly what even half throttle in neutral would produce!

Re: Retarder Temperature Rising, but retarder set to Off

Reply #16 – July 17, 2017, 09:48:19 pm

Closest Authorized Allison dealer is 2 hours away. We are settling in for the night in a small rv park in Kalispell Mt.

Mulling over should I drive to the dealer in Missoula with the VMSPC reporting retarder temps 240-260? Don't even attempt it? Would Couch Net tow me? Would they tow me that far?

Ed

Re: Retarder Temperature Rising, but retarder set to Off

Reply #17 – July 17, 2017, 10:29:30 pm

Code 79 is Sump Fluid Temperature Too High: The selected media item is not currently available.

Unless that is an old code the high temperature might be real. The dash gauge is independent of the internal sensor that flags codes.

Do you have an IR temperature gun to confirm the high temperatures?

It sure seems like the retarder is on (even-though controls are off). Since we have "output" retarders the retardation level corresponds with speed. Mine is not noticeable at slow speeds. You could test it by commanding the retarder on to see if you can feel it engaging - I'm sure you know how it should feel better than anyone else. But it sounds like it might get too hot to even test it. If it sits overnight, the cool down might just release any solenoid valve (or what ever controls it) to release. Someone at an Allison dealer might know how to disable the retarder so you can drive it in. You could also try disconnecting the power to the transmission computer for a few minutes to reset it. Just some wild guessing on my part.

Your transmission is a HD 3066R. Here's a troubleshooting manual I found online (it's only 396 pages):
The selected media item is not currently available.

Re: Retarder Temperature Rising, but retarder set to Off

Reply #18 – July 18, 2017, 10:01:15 am

Quote from: wolfe10 – July 17, 2017, 09:17:59 pm

I would sure not recommend that. Perhaps 1,100 to 1,200 RPM, which would take very little throttle in neutral.

Can't see recommending "governed redline" which is exactly what even half throttle in neutral would produce!

I would only run it at max rpms for a short period to see if the oil temp started dropping (which it should if something else isn't wrong) before settling back to around 1500 rpm which is slightly over 1/2 of governed rpm on the little screaming 3116. I wasn't referring to foot position and I realize that "1/2 throttle" could be confusing. I would want more coolant circulating and air moving through the radiator than what I can get at low idle.

Re: Retarder Temperature Rising, but retarder set to Off

Reply #19 – July 18, 2017, 11:48:29 am

Check codes for a code 33 with a sub code of 12 or 23, it indicates transmission temp sensor failure.

Re: Retarder Temperature Rising, but retarder set to Off

Reply #20 – July 18, 2017, 01:09:20 pm

Just to clarify because some of the helpful suggestions are confusing me. I am getting high temperature readings for the Retarder Oil Temperature (280 was yesterday's highest) on my VMSPC. Transmission Oil Temps are also than normal higher but around 220. Engine coolant seems to be fine.

I took her out this morning for a short drive. VMSPC show the temp to be 60 degrees, same as ambient temp. Normally when driving the Retarder Oil Temp will be around 179 degrees, then climbing whenever I apply the retarder. This morning I never turned on the retard button and the joystick was off also. When I would accelerate the temps just started to rise. As I pressed on the "accelerator" the temps would rise as high as 240 degrees.

Re: Retarder Temperature Rising, but retarder set to Off

Reply #21 – July 18, 2017, 04:37:04 pm

Just curious, on your drive this morning did you ever notice the retarder working or only the temp rising? Did you try turning it on to see if there was a difference? Hope you can get it sorted out soon.

Re: Retarder Temperature Rising, but retarder set to Off

Reply #22 – July 18, 2017, 05:38:33 pm

Quote from: Dave Larsen – July 18, 2017, 04:37:04 pm

Just curious, on your drive this morning did you ever notice the retarder working or only the temp rising? Did you try turning it on to see if there was a difference? Hope you can get it sorted out soon.

Thanks Dave, only the temp rising, I did not touch the button or joystick. The retarder did work when I turned it on after driving for a while and the temps were already over 200 degrees. So I shut it off.

Re: Retarder Temperature Rising, but retarder set to Off

Reply #23 – July 18, 2017, 05:55:09 pm

SO, bottom line is that someone needs to verify how to disable the retarder at the transmission.

That information would be of benefit if anyone else experiences an overheating transmission related to defective retarder activation.

Yes, I know-- we do not have 100% proof that that IS the root cause, but a good "work around" in any case.

Re: Retarder Temperature Rising, but retarder set to Off

Reply #24 – July 18, 2017, 06:16:17 pm

I take it that trans temp sensor still has not been checked to see if it's working or giving erroneous readings? Seems like that would be the first thing checked. Since the Allison only has one temperature sensor for the fluid pan, it's readings would be the one seen by the Allison ECU and a ProLink 9000 if plugged in. The Allison does have a retarder temp sensor. Wonder how it's reading?

Anyone call an Allison shop yet for advice?

Pierce

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