Roadtrek 210 4L80E transmission overheating on mountain climbs

[booster]

Hi am from Minnesota and just got back from Colorado going up and down many steep mountains. I was all the way to Durango and back. I have a 2008 Chevy 210 P and I didn’t do anything on the front end my van is stock with the original radiator no trans cooler other than what’s in the radiator. I didn’t modify any Transmission shift points. Everything is completely stock. There’s already too much heat in my opinion flowing through the radiator and the air conditioner so I didn’t want to introduce any more heat on the front end so I left the transmission go into the radiator but on the return line before it gets back to the Transmission I cut the line and spliced in a aftermarket cooler. The cooler has its own fan and its own in-line thermostat so when it gets hot enough it’ll kick on and when it cools off enough, it will shut itself off. I also installed the B&M transmission temp gauge on the van in line to monitor what was going on and on my longest steepest climb in Colorado pulling a Goldwing with our van loaded down quite heavy to begin with my trans temp never got above 210 most of the time it was at 160° cruising down the road. I installed this aftermarket cooler underneath the van pretty much under the driver seat where there is kind of a open area now I have absolutely zero worries going up and down steep mountains

What gear and speed were you climbing with?

 

[peteco]

Hi am from Minnesota and just got back from Colorado going up and down many steep mountains. I was all the way to Durango and back. I have a 2008 Chevy 210 P and I didn’t do anything on the front end my van is stock with the original radiator no trans cooler other than what’s in the radiator. I didn’t modify any Transmission shift points. Everything is completely stock. There’s already too much heat in my opinion flowing through the radiator and the air conditioner so I didn’t want to introduce any more heat on the front end so I left the transmission go into the radiator but on the return line before it gets back to the Transmission I cut the line and spliced in a aftermarket cooler. The cooler has its own fan and its own in-line thermostat so when it gets hot enough it’ll kick on and when it cools off enough, it will shut itself off. I also installed the B&M transmission temp gauge on the van in line to monitor what was going on and on my longest steepest climb in Colorado pulling a Goldwing with our van loaded down quite heavy to begin with my trans temp never got above 210 most of the time it was at 160° cruising down the road. I installed this aftermarket cooler underneath the van pretty much under the driver seat where there is kind of a open area now I have absolutely zero worries going up and down steep mountains

I have the same transmission cooling setup as you in my 2006 RT 210P. My transmission temps have never gone high but I'm not towing as heavy as you. My problem is engine temperature. On a climb like you did I have to turn the heater on to keep the temps under control. I do regular coolant changes, have changed the fan clutch twice to a heavy duty unit and replaced water pump a couple years ago. Nothing changed with any of these. What were your engine temperatures on these climbs?

 

[booster]

It is possible the poster from Minnesota that saw 210 tops while towing is looking at a different temp than most of the other folks on here who are using a Scangauge that measures the temp internally, I think someplace in the valve body. A Scangauge reacts very quickly to load when it goes on when climbing and pan temps react quite slowly. The out to the cooler line is usually someplace in between. As mentioned it would also be good to know the speed and gear it was in so we can see if it had the converter locked/unlocked or a point where it might be going in and out. An very large unbody cooler with it's own fan can have a lot of capacity for certain, but it is also likely in an area of hotter air also so that is downside.

 

[Wheelhorseman]

On the steep climbs 2nd gear going up with engine rpm’s about 3300 and coming down at least 3300 holding the van back to minimize braking and I am measuring the trans temp after the radiator cooler and before it goes into the auxiliary cooler because i didn’t want to splice into the supply line since I was going to cut the return line for the auxiliary cooler anyway so my temps would be a little higher if measured on the supply line and as far as it being warmer under the van it obviously is warmer then the ambient temperature outside but with the van moving it shouldn’t be that bad. Like I said before before I ordered anything I took the grill off and looked things over and I decided that I didn’t want to put transmission coolers out in front of the radiator because the area is really congested and restricted and struggles for airflow in its stock form and by putting the coolers out in front. It would only make the engine run hotter and the air conditioner be less efficient with less cool air and less air flow That’s why I decided to put mine underneath and oversized the cooler because of the warmer air that would be flowing to it

 

[booster]

On the steep climbs 2nd gear going up with engine rpm’s about 3300 and coming down at least 3300 holding the van back to minimize braking and I am measuring the trans temp after the radiator cooler and before it goes into the auxiliary cooler because i didn’t want to splice into the supply line since I was going to cut the return line for the auxiliary cooler anyway so my temps would be a little higher if measured on the supply line and as far as it being warmer under the van it obviously is warmer then the ambient temperature outside but with the van moving it shouldn’t be that bad. Like I said before before I ordered anything I took the grill off and looked things over and I decided that I didn’t want to put transmission coolers out in front of the radiator because the area is really congested and restricted and struggles for airflow in its stock form and by putting the coolers out in front. It would only make the engine run hotter and the air conditioner be less efficient with less cool air and less air flow That’s why I decided to put mine underneath and oversized the cooler because of the warmer air that would be flowing to it

Thanks, the explains a lot of it, I think. I need to check the older post for the details to make certain, but it appears that you were into a range where the torque converter was locked at least a lot of the time. The shift and lockup settings are in mph so do happen to recall what the speed was climbing. I think that rpm will give enough to lockup in the mid 50s mph at full throttle. Where we wind up with an issue is on roads that where you can't go that fast like winding two lane climbs with under 50mph speed limits as there is no way to go fast enough to lock up even in second gear. Your speed would also help explain the not extreme engine heat.

You might want to put on a Scangauge or other OBD monitor to see the actual transmission temp that the PCM and fluid are seeing inside the transmission, also, as that will be more real time temperature and what the PCM will use to decide whether to go into hot limp mode or not.

My guess is that is if you wind up on a slower, steep, road you will get to max temps just like the rest of so being aware of that would be good to know. With no lockup allowed in low gear you limit out on low speed for keeping the transmission and engine cool in second gear.

On edit: I just looked at the lockup chart that is in the PCM and my rpm vs speed spreadsheet from the older discussion and at 3300 rpm you will just about at the 50 mph that is needed for lockup in second gear and high throttle position so what I have above is likely what went on with your climb. 5mph slower and it probably would have been much different from a heat standpoint.

The lockup chart and rpm/vs speed spreadsheet are in this discussion: you would need to convert your stock tire size if you have them so you tire revs would be 683 rev/mile instead of 657 rev/mile and speed a bit slower but speedo an computer won't know that unless you have done speedo correction and we hadn't at that time.

Overheat discussion link

 

[Bangorbob]

When we explain steep mountains and hills, it isn't the same as naming the mountains and how steep they are. A lot of people see a 3000 ft mountain as high. Going to Denver from the east is very steep and would like people to compare apples to apples. That is a 7% grade going up to 11,000 ft. Just a little rant.

 

[booster]

When we explain steep mountains and hills, it isn't the same as naming the mountains and how steep they are. A lot of people see a 3000 ft mountain as high. Going to Denver from the east is very steep and would like people to compare apples to apples. That is a 7% grade going up to 11,000 ft. Just a little rant.

I totally agree with you on that for sure, as it is all relative. Going out of near north of Denver up to the visitor center from the east to 11 or 12K feet is slow at 35mph, steep, and curvy and is where we had our most problems with heat and went back to there to test changes. Going up the Eisenhower was absolute cake, even stock so very different.

The same thing applies to a lot of things on the forum as posters are giving information in different ways or taking readings differently, as it this post where the temp given is from a different location of the system so can't be compared directly to what the rest of us see for temps.

As with most things, the quality of the answers is often related directly to the quality and completeness of the questions asked, so very important that we get all the details even if they seem trivial.

 

[youngnretired]

TWX, just wondering if your van had a full floater 4.10 axle in it, is the GVCW rating still 9600lbs or greater?

 

[booster]

TWX, just wondering if your van had a full floater 4.10 axle in it, is the GVCW rating still 9600lbs or greater?

TWX will probably come in also, but on a Roadtrek built on the Express van 3500 will all have the rear rated at the rear tire max rated capacity, not the axle. A full floater with more inherent capacity will still carry a 6084 rear axle max weight which is the capacity of the E rated 245/75/16 tires and 9600 gross vehicle weight. Once the van is built and stickered, you can put on bigger tires and a stronger rear axle, but it will NOT change the rated load capacity if you happened to get inspected or got in an accident where and insurance company weighed it as overweight.

 

[youngnretired]

Yea, that makes sense that the tire is the limiting factor.

 

[Wheelhorseman]

OK, I apologize for the delay. Here is some pictures of how I installed my cooler underneath the van. You can see it is at a downward angle. It has a in-line thermostat switch that kicks it on when it hits 180 degrees and shuts it off at 160 degrees I also installed a Transmission temp gauge. I know it’s not an instant read but it gives me a good idea of what the van is doing again. The hot fluid goes to the transmission cooler in the radiator, then comes out and then I spliced in the return line and sent that to the aftermarket coolerp that I installed and then back to the Transmission. We’re going to Glacier and Yellowstone in a month so I will pull it out and maybe get some better pictures if I remember and tidy the wires up now that I know that it works excellent.
I used Hydraulic hose because I don’t think too much of the hose they sent with the kit, but I also make hydraulic hoses so I can do that easily. The location of the cooler is pretty much behind the driver seat next to the driveshaft behind the transmission, I was laying on the ground on the driver side, taking pictures. That’s why I took the one of the side of the van for a location reference. You can see the front tank drain in the one picture.

 

[peteco]

Here is some pictures of how I installed my cooler underneath the van.

Thanks. Looking forward to your mountain trip to test the transmission cooling system. Hope it works well and also keeps the engine temperature down.

 

[peteco]

Suggestion: Get a Scangauge or similar to monitor both transmission and engine temperatures. I have the Scangauge 2 and it has worked great. Booster just installed the Scangauge 3 reported here:

Scangauge 3 Real-World Usability and Mounting Notes

A couple of discussions on here addressed the Scangauge 3 and it's capabilities, but with some unknowns and questions for me about usability in the real world. I did finally get one to find out if it would address the things that I would want over the Scangauge 2 we have had for many years...

www.classbforum.com

 

[booster]

OK, I apologize for the delay. Here is some pictures of how I installed my cooler underneath the van. You can see it is at a downward angle. It has a in-line thermostat switch that kicks it on when it hits 180 degrees and shuts it off at 160 degrees I also installed a Transmission temp gauge. I know it’s not an instant read but it gives me a good idea of what the van is doing again. The hot fluid goes to the transmission cooler in the radiator, then comes out and then I spliced in the return line and sent that to the aftermarket coolerp that I installed and then back to the Transmission. We’re going to Glacier and Yellowstone in a month so I will pull it out and maybe get some better pictures if I remember and tidy the wires up now that I know that it works excellent.
I used Hydraulic hose because I don’t think too much of the hose they sent with the kit, but I also make hydraulic hoses so I can do that easily. The location of the cooler is pretty much behind the driver seat next to the driveshaft behind the transmission, I was laying on the ground on the driver side, taking pictures. That’s why I took the one of the side of the van for a location reference. You can see the front tank drain in the one picture.

Do you have link or a part number for the cooler you used? I would be very interested in looking at the specs and sizing information for future reference.

As has been mentioned by several, you may want to put an OBD monitor on it like a Scangauge as they measure the temp in the valve body area and give a better and much faster indication of the oil at one of the hottest areas. GM would put that sensor in a place the would indicate problems quickly to report them to the PCM. Pan gauges lag the factory output by a lot, with the most lag coming on short, very steep, grades. I had both gauges on ours for several years checking the relationship.

You might also be able to get a temp sensor that fits into the pressure testing port and a gauge to go with it. That is what I have on my 4L60 trans in my 96 Buick Roadmaster 5.7L powered wagon. IMO you might as well spend the money on a monitor that will give you the factory sensor temps for trans, water, plus a lot of other information. We did the test run on our Scangauge 3 that just replaced our Scangauge 2, and it is a very nice unit, IMO.

 

[Wheelhorseman]

Thanks. Looking forward to your mountain trip to test the transmission cooling system. Hope it works well and also keeps the engine temperature down.

Oh it works well, we live in southern Minnesota and went to Durango Colorado in the middle of June and went up and down mountains with a 7% grade pulling my gold wing with us

Do you have link or a part number for the cooler you used? I would be very interested in looking at the specs and sizing information for future reference.

The cooler I used has the 6an inlet and outlets and is a 16 pass I could upgrade in the future if I would ever need it to the bigger cooler derale has with 8an fittings and is a little bigger and is a 24 pass cooler

 

[booster]

Thanks for the information, I appreciate it. That is a tube and fin style cooler with probably a 10" fan. They rate it at 14,000 btu and the fan at 650cfm.

That is a smallish cooler and tube and fin is considerable less efficient the plate and fin or stacked plate style coolers. I would not be surprised if it is not enough capacity for what you are doing and seeing, but need a tough test to find up, particularly a test that holds the trans in a non lockup range of speed and rpm. A Scangauge 3 will display gear number and converter slip so you can tell what your gear and lockup of the converter state are. We had a cooler of higher BTU rating than that by a lot and it was not nearly enough for the tough climbs. I will say BTU ratings are often stretched by varying amounts so more size and design will indicate better about actual real world cooling.

We are from Minnesota also. What part of the state are you in? We are in the exurbs of Minneapolis in Andover right at the Oak Grove border.

 

[peteco]

It has a in-line thermostat switch that kicks it on when it hits 180 degrees and shuts it off at 160 degrees I also installed a Transmission temp gauge.

How does the inline thermostat switch work? Does it re-route the fluid flow around the cooler? The picture looks like it is setup to block the flow to the cooler, but that doesn't seem right.

 

[Wheelhorseman]

We are from Minnesota also. What part of the state are you in? We are in the exurbs of Minneapolis in Andover right at the Oak Grove border.


We are south of the cities just east of Medford

 

[Wheelhorseman]

How does the inline thermostat switch work? Does it re-route the fluid flow around the cooler? The picture looks like it is setup to block the flow to the cooler, but that doesn't seem right.

The fluid always flows through the cooler the thermostat switch simply turns the cooling fan on and off as needed

 

[youngnretired]

Just a word of caution for you with the install under the van. It's location may be subject to getting hit by rocks or other debris coming off the road, and if you drive down a dirt road in the rain, you may get enough mud coming off the road to plug up the fins on the radiator. It may be high enough where it's not an issue, but just want to mention it for you to keep in the back of your mind.