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outwestbound
05-27-2018, 05:11 PM
Greetings.

Have a T1N in the form of a 2006 Itaska Navion 23J class c motorhome, which is a Sprinter 3500, 2.7L, I5 with a 722.6 automatic transmission. The chassis manufacture date is November 2005.

Purchased an iCarsoft MB II reader and am looking at the actual values on the transmission tempature.

Does anyone know where exactly the temp sensor is? Is it the temp of fluid in the TC, transmission, outgoing line to the radiator, or maybe the return line?

Thanks,

John

Bobnoxious
05-27-2018, 05:28 PM
From 06 service manual

lindenengineering
05-27-2018, 05:57 PM
In the circuit board away from prying hands.
Dennis

outwestbound
05-27-2018, 06:26 PM
From 06 service manual

Thanks for responding and please forgive my ignorance. Here's my issue:

I installed a Derale 13870 remote oil tranny cooler with a Derale in-line thermostat that is suppose to kick the cooler fan on at 180 degrees F. The in-line T stat is on the cooler intake valve and the cooler is placed into the transmission's return line from the radiator, per instructions. The cooler (cooler hose runs) is about 50" from the transmission, behind the transmission, so the rubber lines to read back to the cooler end up being longer than OEM. The cooler is a 67,000 BTU/hour unit with a t state controlled fan.

I tested the cooler yesterday for the first time and the cooler fan did not kick on when the code reader tranny temp hit 180 degrees F, which is 82 C. I bought a laser temp measuring tool to try to figure out the differences in oil temps at different locations. At this point, I'm not sure if the cooler is wired incorrectly, or the heat at the cooler T stat location just isn't hitting 180F.

This is why I'm wondering about the sensor. I'm going out tomorrow to get more readings so see if there is some consistency in the scan code reader (sensor) temp and the temp I'm getting wit the laser right at the transmission's outgoing line to the radiator. I assume they will be close.

I need to recheck, but there appears to be about 20 degrees F less in temp at the cooler location, than there is coming out of the transmission. I suppose this is normal, given the fluid passes through the radiator and lines before getting to the T state at the cooler.

It seems like the transmission would need to hit about 200F (per the sensor indication) in order to get the T state at the cooler to 180F. Does this seem rational; that the oil would Have to get that hot before the cooler even engaged at all? I gather that 175ish is within oil design, but I don't know about 200. I'm just wondering if I need to try to get the fan to kick on sooner, or whether it's dong exactly what it's designed to do. Everything was installed to Derale spec. I'll call Derale also, but the T state isn't adjustable, so "I guess" the only way to get it to kick on sooner would be to relocate it, which means back to the transmission shop.

Any thoughts appreciated.

Bobnoxious
05-27-2018, 09:38 PM
My pleasure. Regret I cannot be of more assistance but, frankly, I am a Sprinter apprentice and considering the complexities of Sprinters, I'll be one for a long, long time.

Curious, why do feel the need to add a tranny cooler? Are there indications the tranny is overheating? I have been on this forum everyday for over three-years and cannot recall anyone adding a tranny cooler. IMHO, the existing cooler, if it has one, (?) appears to be more than sufficient. Perhaps, more knowledgeable members can chime in? Good luck.

outwestbound
05-27-2018, 09:59 PM
My pleasure. Regret I cannot be of more assistance but, frankly, I am a Sprinter apprentice and considering the complexities of Sprinters, I'll be one for a long, long time.

Curious, why do feel the need to add a tranny cooler? Are there indications the tranny is overheating? I have been on this forum everyday for over three-years and cannot recall anyone adding a tranny cooler. IMHO, the existing cooler, if it has one, (?) appears to be more than sufficient. Perhaps, more knowledgeable members can chime in? Good luck.

Good question. My vehicle's transmission is overloaded, which results in a high transmission failure rate, due to the torque converter overheating. This is what I've learned.

Winnebago delivers these motorhomes to customers with like 1,100 pounds or so of cargo capacity, which includes the passengers, LP gas and water. MB upgraded the transmissions with the next model in 2008, but these 2006 and 2007 Winnebago motorhomes have notoriously weak transmissions, from everything I've read. Even the service manual recommends a cooler if near the GVWR. My GVWR is 10,200 and I'll be at 10,200, whereas many, or most motorhome users, are over due to the inadequate payload capacity of the vehicles as delivered.

I'm shipping mine to South America for a year and beating the crap out of it, so I'm hoping for the best.

Patrick of M
05-27-2018, 11:05 PM
Maybe you can rig a manual overide for the trans cooler. That way you can try cooling in advance of big hills etc and various other situations. I had a problem with a Eurovan where it couldn’t keep up with cooling, the high speed dual fan kicked in too late. I added additional wiring and a dash switch, when I saw a big climb coming I turned on the fans before it got hot, this smoothed out the temp fluctuations a lot. A little more hands on than most like, but driving a van is boring, it doesn’t take much to monitor some extra stuff.

calbiker
05-28-2018, 12:18 AM
Is the additional cooler inserted at the right side (passenger side) of the transmission? I believe that would be after the radiator.

The tranny temp sensor should be measuring the fluid in the pan.

I just got back from a trip where I recorded temperatures at various locations. To my surprise, the hottest location that I measured is the tranny pan (Tra_Pan). Next hottest is the tranny Al pipe going to the radiator (Tra_Out), then the tranny Al pipe coming from the radiator (Tra_In), then the temp sensor mounted on top of the coolant thermostat (Eng_Thermo), then the coolant big rubber hose going to the radiator (H2O_Out) and last the coolant big rubber hose going to the engine (H2O_In). The x-axis is time in minutes traveled.

The largest temperature differential between Tra_Pan and Tra_Out is 20F (To Pinnacles 200 min mark). I find the To KirkCreek plot interesting as I'm traveling over the coastal mountain range (Nacimiento-Fergusson Rd.) The tranny might be getting hotter when descending than ascending. About the 233 min mark I was on level HW1 (Big Sur) and temperatures rapid declined.

Tranny temps are almost always hotter than engine coolant. While the radiator does a great job cooling engine coolant, tranny fluid is cooled minimally.

I'm not convinced the T1N 3500 torque converter failure (in heavy MHs) is related to excessive temperature. It could be metal fatigue. They're all failing around 100 k.

I may have a simple solution cooling the tranny that I'm working on.

outwestbound
05-28-2018, 12:18 AM
Maybe you can rig a manual overide for the trans cooler. That way you can try cooling in advance of big hills etc and various other situations. I had a problem with a Eurovan where it couldn’t keep up with cooling, the high speed dual fan kicked in too late. I added additional wiring and a dash switch, when I saw a big climb coming I turned on the fans before it got hot, this smoothed out the temp fluctuations a lot. A little more hands on than most like, but driving a van is boring, it doesn’t take much to monitor some extra stuff.

Thanks. I was thinking that too. I discussed this originally with Derale, and they said not to do it because they had some people use the switch incorrectly, resulting in the fan being permanently off. Instead at Derale's advice, I installed a simple light on the dash, which illuminates when the fan comes on. This just lets me monitor it.

I'd have to think about this, but I think I can put a switch on my dash that bypasses the in-line T stat, but leaves the t state in place (so 2 hot wires going to the fan). If this worked, leaving the dash switch off (accidentally for some reason) would not stop the t stat from turning the fan on, because both the t stat and remote dash switch would each be carrying a hot signal to the cooler fan. The fan would turn on with "either" switch turned on. I think this will work.

Thanks for the input. This may be very important in South America, which is like driving 20,000 miles through the mountains of Colorado, except the mountains are higher down there.

outwestbound
05-28-2018, 12:45 AM
Is the additional cooler inserted at the right side (passenger side) of the transmission? I believe that would be after the radiator.

The tranny temp sensor should be measuring the fluid in the pan.

I just got back from a trip where I recorded temperatures at various locations. To my surprise, the hottest location that I measured is the tranny pan (Tra_Pan). Next hottest is the tranny Al pipe going to the radiator (Tra_Out), then the tranny Al pipe coming from the radiator (Tra_In), then the temp sensor mounted on top of the coolant thermostat (Eng_Thermo), then the coolant big rubber hose going to the radiator (H2O_Out) and last the coolant big rubber hose going to the engine (H2O_In). The x-axis is time in minutes traveled.

The largest temperature differential between Tra_Pan and Tra_Out is 20F (To Pinnacles 200 min mark). I find the To KirkCreek plot interesting as I'm traveling over the coastal mountain range (Nacimiento-Fergusson Rd.) The tranny might be getting hotter when descending than ascending. About the 233 min mark I was on level HW1 (Big Sur) and temperatures rapid declined.

Tranny temps are almost always hotter than engine coolant. While the radiator does a great job cooling engine coolant, tranny fluid is cooled minimally.

I'm not convinced the T1N 3500 torque converter failure (in heavy MHs) is related to excessive temperature. It could be metal fatigue. They're all failing around 100 k.

I may have a simple solution cooling the tranny that I'm working on.

Hi Calbiker. Yes, the transmission shop tied directly into the steel lines on the passenger side. We tied into the steel so that we could keep the rubber lines as short as possible, because my remote cooler is behind and on the driver's side of the vehicle, about 45"-55" diagonally from the transmission. It's mounted with a great deal of open air around it, plus I installed a little DIY dryer vent scoop to push cool air in front of the cooler.

Not sure why the transmissions are failing, but I'm assuming cooler fluid is better than hotter fluid. Because I have enough of it, I just threw money at the problem in the form of the Derale 13870, which I think is the biggest they sell. I had plenty of room to install it; so why not? It's a 40 row, stacked plate with an 800 CFM fan. It it dosn't work, who knows.

Your data is interesting. Even without my cooler fan, I did notice that the transmission temp is consistently below the engine temp, but I don't think on my first trail that I raised the tranny temp enough to activate the fan. Ultimately, I'd like to get the delta from transmission line out to transmission line in to a large enough number to hopefully keep the vehicle on the road.

I'll be interested if you figure out an improved method. I'll collect some more data tomorrow.

Thanks for your input.

Patrick of M
05-28-2018, 12:50 AM
Thanks. I was thinking that too. I discussed this originally with Derale, and they said not to do it because they had some people use the switch incorrectly, resulting in the fan being permanently off. Instead at Derale's advice, I installed a simple light on the dash, which illuminates when the fan comes on. This just lets me monitor it.

I'd have to think about this, but I think I can put a switch on my dash that bypasses the in-line T stat, but leaves the t state in place (so 2 hot wires going to the fan). If this worked, leaving the dash switch off (accidentally for some reason) would not stop the t stat from turning the fan on, because both the t stat and remote dash switch would each be carrying a hot signal to the cooler fan. The fan would turn on with "either" switch turned on. I think this will work.

Thanks for the input. This may be very important in South America, which is like driving 20,000 miles through the mountains of Colorado, except the mountains are higher down there.

Yeah that’s basically what I did, I used a switch to control some relays so that I could power the fans when their temp sensor had not turned them on yet, but I left the auto system intact so the fans could get turned on automatically as well. My system had the one default of sometimes I left it on, and then the engine temp would go a little low, but not really a problem. Conceivably a timer switch would help with that. All of this was for a gas Eurovan that would get hot in traffic and up big hills, even with a brand new thermostat. Rigged that up on the road in Mexico when I couldn’t stand watching the temp fluctuate so much. BTW many aux trans coolers are plumbed in with a bypass circuit, thermostat controlled, so that trans oil is not overcooled, you probably won’t want that but in cold places that is sometimes required.

outwestbound
05-28-2018, 01:06 AM
BTW many aux trans coolers are plumbed in with a bypass circuit, thermostat controlled, so that trans oil is not overcooled, you probably won’t want that but in cold places that is sometimes required.

I thought about the bypass, which I decided I don't need. It's just so much more to go wrong. I may well encounter some 15-30 degree Fahrenheit weather down there, but that will be the unusual case for sure. In cold weather, I figured I'd kill the cooler fan, plug the little ram air vent and maybe put a fire resisted cloth around the cooler. For that matter, I could cover the pan also. I think the radiator would keep the fluid warm enough, especially if I let it warm up for 15 minutes before driving it.

owner
05-28-2018, 10:07 AM
The internal temp sensor is inside the conductor plate and measures pan fluid temp.

Have you considered using one of these deep pans?
https://www.yourcovers.com/transmission_nag1.php

Not only will it help dissipate more heat from the fluid in the pan, but it also adds over 25% more fluid to the system. Lots of sprinter RV users putting the deep-centre version on their van,s scroll to the bottom https://www.yourcovers.com/transpan_11124.php

outwestbound
05-28-2018, 11:21 AM
The internal temp sensor is inside the conductor plate and measures pan fluid temp.

Have you considered using one of these deep pans?
https://www.yourcovers.com/transmission_nag1.php

Not only will it help dissipate more heat from the fluid in the pan, but it also adds over 25% more fluid to the system. Lots of sprinter RV users putting the deep-centre version on their van,s scroll to the bottom https://www.yourcovers.com/transpan_11124.php

Thanks for the reply.

Yes, I considered the deeper pan (which offers an easy way to install a temp gauge also), but decided the reduced clearance was too great a risk, given that I'm heading to South America.

The remote cooler adds 26 oz plus the 3/8" lines, so I figure I've added 1.15 liters to the total volume. One thing I didn't do, but would have maybe done if I'd have used a smaller cooler, is run my lines to and from the cooler in steel. Having steel lines would dissipate heat even more, based only on what I've read. The shop where I did the "plumbing" for the cooler could have easily done steel instead of the 3/8" rubber, but steel would have been another $600 in labor or thereabouts I think he said.

My goal was to keep it simple due to risk of equipment failure, so I avoided extra lines and fittings for auxiliary filters, bypass lines, tempature gauges, etc.

If I can figure out the temp difference between the iCarsoft's actual transmission temp per the sensor in the pan and sprinter's dash gauge for engine temp, and assuming this relationship is linear, I can keep an eye on the transmission using the engine gauge. Also, I'll leave the dash light that I installed in place, so a light will illuminate when the Derale in-line t-stat kicks the cooler's fan on. Together with a manual switch to turn the cooler fan on, I think this will all work out.

Mountain climbing down there will be brutal. Climbing 8-10,000 feet in a day wouldn't be unusual. Slow, winding, switching roads are also typical on ascents. We'll see.

outwestbound
05-28-2018, 05:18 PM
I had a bad ground connection, so the test yesterday wasn't valid. Fixed the ground and went out again this morning.

In Florida, it was difficult to get the transmission hot enough to kick on the fan. In general (without the cooler fan running, but with fluid still circulating through the radiator and the remote cooler), the transmission ran 10 degrees F cooler than the engine (assuming the dash engine guage is accurate).

The in-line T stat kicked turned the remote cooler fan on 3 times.

At a reading of 87 degrees C on the iCarsoft scanner (189 F)(which I now understand to be the pan temp), it kicked on and in two minutes, the temp dropped to 71C or 160F.
At 87C or 189F, it kicked on again and the temp dropped to 72C or 162F.
At 89C (192F), it kicked on again and the temp dropped to 73C or 163F.

In each case, the fan only took 1.5-2 minutes to reach the reported low temp.

I don't think this was much of a test, because I barely hit enough temp to get the fan on over these flat Florida roads, then it dropped the temps like a rock. I had to drive it much faster than I normally would, to get the engine temp up. When I get into some decent hills or mountains, I suspect that will be the test; namely, whether the cooler will keep the transmission from running up over 200 and hotter. The way the temps dropped like a stone during this initial test, I'm hopeful.

calbiker
05-28-2018, 06:21 PM
Here's another temp plot. These temperatures are from actual Sprinter sensors. The tranny fluid temp takes over 30 min of driving time (on level freeway) before it gets to coolant temp. Perhaps you're measuring tranny temp before it stabilizes. Ambient temp remains around 58 F.

Not sure why the transmission sensor (yellow plot) has spikes. I'm planing on putting an oscilloscope on that line to see what's up.



Your data is interesting. Even without my cooler fan, I did notice that the transmission temp is consistently below the engine temp, but I don't think on my first trail that I raised the tranny temp enough to activate the fan.

outwestbound
05-28-2018, 07:05 PM
Here's another temp plot. These temperatures are from actual Sprinter sensors. The tranny fluid temp takes over 30 min of driving time (on level freeway) before it gets to coolant temp. Perhaps you're measuring tranny temp before it stabilizes. Ambient temp remains around 58 F.

Not sure why the transmission sensor (yellow plot) has spikes. I'm planing on putting an oscilloscope on that line to see what's up.

Very interesting. I may have not driven long enough to match the transmission to the engine coolant. I'll be driving a few hours later in the week. Today's ambient temp was about 82F.

I did notice that, even with the cooler fan off, the transmission runs cooler. I guess this is due to about 1.15 liters more fluid plus the effect of the cooler itself.

I'm going to north Florida where I may find some long uphill grades to try the cooler out at higher temps.

As to the spikes, I don't have the knowledge to know the consistency of the fluid's travel through the system. If on the highway always in drive, I can't understand why the pump would be inconsistent, resulting in temp spikes along the line/ across the sensors.