Towing with cruise control

[fooldawg]

Just purchased a 2016 LC and tow a small trailer with a total weight of 2200 lbs. I set the ECT on and limit the highest gear at 7. The owners manual states no towing with cruise...Is it really a bad idea to use the cruise on trips over mostly flat terrain ? Thanks, Dave

 

[LCHardriver_02]

The recommendation in the owner's manual is conservative. If you are on flat terrain with a light load, you could probably use the cruise control, but you would want to closely monitor your transmission shifts, as it can overheat the transmission fairly quickly.

I do not use Cruise when I tow and keep my 2010 in 4th, but I tow closer to 5500lbs on my trailer.

 

[chilibit]

My intuition is that the cruise system will function just fine. Avoiding cruise while towing may be driven by safety and liability concerns. And they might be valid concerns.

 

[CLHickman]

Dave,

I've used cruise while towing a small enclosed trailer (Uhaul) with a rough weight of 2000lbs. I utilized ECT and had zero problems at all. I will admit that I did not utilize the manual gear restriction. I kept an eye on the RPMs and frequency of shifting like @LCHardriver_02 mentioned.

I'll admit though, I was doing roughly 65MPH and was constantly being passed. So, I didn't have to worry about the overtaking process. The terrain was flat and level.

--Chris

 

[linuxgod]

I have a 2013 (6-speed) and a 5000# trailer. Had a chance to tow it for the first time last weekend. My LC setup is currently stock (no lift, no re-gearing, and no armor). The trailer is 8' wide, 9' tall, and 23.5' long (including hitch), dual axle, and runs about 600# on the tongue. I run a WD hitch and a single anti-sway. When I pulled my trailer over the weekend I had a WiFi OBD2 reader attached and was running EngineLink to read the data. Here are my thoughts on towing with my setup... I know it's a 2013 but my results should generally apply to your setup as well.

Limiting to 4th (In the 2013, 4th is 1:1, IIRC in the 2016 it's 6th) I was cruising at 65-70 in mostly flat Illinois/Wisconsin (I-94) and ran around 2800RPMs +/-. I got ~10.5MPG at that speed (the instantaneous MPG reading from OBD2 was pretty steady between 10.2 and 10.8MPG). I tried running in 5th for a while but I found I had to lay into the gas pedal more to keep it at 65, so my gas mileage actually went down. Unless I was driving 55, using OD provided no MPG benefit.

I also watched the temps closely during the trip. Outside it was ~65F out. Intake temp was reading about ~90F (typical). My trailer was at the shop getting the bearings repacked so I drove about an hour to pick it up and then about an hour after I hitched up, thus I got some great comparison #'s:

• Without a trailer running in top gear (6th) the transmission pan temp reached 195F (+/- 1F degree), and the torque converter was anywhere from 195F (when fully locked) to about 208F (for instance when accelerating from 60-70). The higher TC temp didn't affect the pan temp much. Once the TC locked up again at ~70MPH the temps would both stablilze around 195F again.
• With the trailer running in 4th gear the pan temp stayed around 196F (+/-1F). Both the TC and the pan temp would read the same when cruising at 65MPH. About 2/3 of the way through the trip I tried running in 5th gear (first OD). The TC temp would climb (at one point it hit 213F) and the pan slowly climbed up to about 202F over the span of about 5 minutes before I put it back in 4th. At that point the temps slowly dropped down to 195F again. Also, I definitely noticed the weight of the trailer a LOT more when towing in 5th than in 4th.

In short, don't tow in overdrive - the gas mileage difference is small and OD generates heat in the transmission, especially if the ambient temps are warmer and/or you're pulling through hilly terrain. Yes if you're pulling a 2000# 4x5x8 uhaul trailer you can probably run in 5th or 6th without any damage, but if you're pulling a smaller trailer running in your 1:1 gear (6th in your case) will have less impact on your MPG than it does for me, so the $ savings is minimal.

As a side note, the weight of my gear (cooler, dog, etc) and family sinks my rear by about 1.5", and the trailer reduces another 3.5" (even with weight distribution running 4 links). I ordered a set of Firestone 4164 help air bags for the rear and an Air-lift compressor kit when I got back home on Sunday and am going to have my mechanic install them next week (I'd do it myself but I don't have a place to work on the truck except a cobblestone driveway that isn't completely flat - terrible for jack stands). I plan to write a full post on my towing experience in a couple weeks once they're installed and tested.

 

[CLHickman]

@linuxgod, great write-up! That is a handy analysis with good data. Can't wait to read your full report once everything is installed.

--Chris

 

[Romer]

well I just towed my Kimberley Karavan at over 4000lbs back and forth to Moab with Cruise Control on all the flat terrain doing 80. I had no issues.

Nice write-up above. I will have to remember 4th gear

 

[linuxgod]

well I just towed my Kimberley Karavan at over 4000lbs back and forth to Moab with Cruise Control on all the flat terrain doing 80. I had no issues.

Nice write-up above. I will have to remember 4th gear

If you ever tow, I highly recommend getting an elm327-compatible obd2 dongle. The single plus a basic obd2 iPhone/android reader is a total of $20 and gives you all sorts of data about your cruiser *before* the warning lights come on.

 

[Romer]

If you ever tow, I highly recommend getting an elm327-compatible obd2 dongle. The single plus a basic obd2 iPhone/android reader is a total of $20 and gives you all sorts of data about your cruiser *before* the warning lights come on.

Great tip. I see lots of variants, wi-fi, BT and many brands. Any recommendations?

 

[linuxgod]

Great tip. I see lots of variants, wi-fi, BT and many brands. Any recommendations?

I bought this one for $15, though any ELM327 reader should work: Mini ELM327 Wi-Fi OBD2 OBDII WiFi For iPhone Car Diagnostic Interface Scanner. Note that this device uses WiFi, so when you connect to the device as a WiFi access point you'll lose data access on your phone (though calls/texts will still work). There are also Bluetooth versions if you prefer, though I suspect if use those you'll lose hands-free capabilities while it's active.

Many people seem to like Torque Pro but I used this $6 iPhone app with it: Engine Link - OBD II vehicle monitoring and diagnosis on the App Store

In EngineLink I added two custom PIDs:

• Toyota A/T Pan Temp. PID 2182. Formula ((((A*256+B)*(7/100)-400)/10). Range -40 to 300. Units are F.
• Toyota A/T TC Temp. PID 2182. Formula ((((C*256+D)*(7/100)-400)/10). Range -40 to 300. Units are F.

And then I made a custom dashboard with 6 small gauges:

• Intake air temp
• Engine coolant temp
• Toyota A/T Pan Temp
• Toyota A/T TC Temp
• Instantaneous MPG
• Average MPG

There's enough space in the dashboard to include 2 more gauges. If I could ever figure out how to get Oil Pressure and Oil Temp I would add them as well. EngineLink will also show OBD2 error codes, so if you ever get a check engine light you can at least pull the code on the spot so you know whether it's critical.

To me the $21 is worth the peace of mind that I'm not cooking the transmission. A/T fluid is designed to run up to 95C (about 200F), and breaks down quickly once you reach 120C (about 245F). I don't know at what temperature the A/T Temp light comes on but I suspect it's over 120C so you could deteriorate the fluid without the light ever coming on. Once A/T fluid breaks down it does a poor job of lubricating and cooling and needs to be immediately flushed.

 

[NLScooby]

Wow @linuxgod this is some fantastic quantitative data!

 

[fooldawg]

Very informative...Thanks for the feedback...I also have a Silverado 2500HD that I normally tow with and I'll just stay with that. It has the advantage of Trailer Sway Control, Auto Grade Braking and Cruise Grade Braking. It's just that the LC is so much more comfortable and less fatiguing on long trips...

Take care

 

[linuxgod]

Very informative...Thanks for the feedback...I also have a Silverado 2500HD that I normally tow with and I'll just stay with that. It has the advantage of Trailer Sway Control, Auto Grade Braking and Cruise Grade Braking. It's just that the LC is so much more comfortable and less fatiguing on long trips...

The LC has trailer sway control, though personally I wouldn't run any decent size box trailer on the highway without an anti-sway bar. I agree the longer wheelbase of the 2500HD is better for towing though, and the 3/4 ton truck wouldn't require a weight distribution setup to keep the rear end from sagging dramatically under the same weight.

 

[linuxgod]

I ordered a set of Firestone 4164 help air bags for the rear and an Air-lift compressor kit when I got back home on Sunday and am going to have my mechanic install them next week (I'd do it myself but I don't have a place to work on the truck except a cobblestone driveway that isn't completely flat - terrible for jack stands).

Air bags are in, following the instructions at LandCruiser 200 - Firestone Coil-rite airbag install. My mechanic and I installed them together yesterday (he'd never done a set either). Bag install and line routing took about 2 hours using his lift. Figuring out how to mount the compressor inside the vehicle took another 2. And then about 90 minutes to hook it up including running power from the battery to the back of the truck (we ran it under the vehicle along the frame rail for now... I may do a cleaner install under the door sills in the future once I get a Blue Sea fuse block).

I'll post some photos after I go hook up my trailer next week. (The link above does a great job of detailing the installation). I only have ~5lbs of air in the bags right now but so far I've not noticed any difference riding around the crumbling asphalt here in Chicago. It does seem like I gained an inch or so of lift in the back, but I want to wait a couple days to see if the suspension just needs to settle a bit. If not I may opt for a set of spacers up front next.

 

[04UZJ100]

I bought this one for $15, though any ELM327 reader should work: Mini ELM327 Wi-Fi OBD2 OBDII WiFi For iPhone Car Diagnostic Interface Scanner. Note that this device uses WiFi, so when you connect to the device as a WiFi access point you'll lose data access on your phone (though calls/texts will still work). There are also Bluetooth versions if you prefer, though I suspect if use those you'll lose hands-free capabilities while it's active.

Many people seem to like Torque Pro but I used this $6 iPhone app with it: Engine Link - OBD II vehicle monitoring and diagnosis on the App Store

In EngineLink I added two custom PIDs:

• Toyota A/T Pan Temp. PID 2182. Formula ((((A*256+B)*(7/100)-400)/10). Range -40 to 300. Units are F.
• Toyota A/T TC Temp. PID 2182. Formula ((((C*256+D)*(7/100)-400)/10). Range -40 to 300. Units are F.

And then I made a custom dashboard with 6 small gauges:

• Intake air temp
• Engine coolant temp
• Toyota A/T Pan Temp
• Toyota A/T TC Temp
• Instantaneous MPG
• Average MPG

There's enough space in the dashboard to include 2 more gauges. If I could ever figure out how to get Oil Pressure and Oil Temp I would add them as well. EngineLink will also show OBD2 error codes, so if you ever get a check engine light you can at least pull the code on the spot so you know whether it's critical.

To me the $21 is worth the peace of mind that I'm not cooking the transmission. A/T fluid is designed to run up to 95C (about 200F), and breaks down quickly once you reach 120C (about 245F). I don't know at what temperature the A/T Temp light comes on but I suspect it's over 120C so you could deteriorate the fluid without the light ever coming on. Once A/T fluid breaks down it does a poor job of lubricating and cooling and needs to be immediately flushed.

The light comes on at 302F reading downstream of the TC.

 

[04UZJ100]

I have a 2013 (6-speed) and a 5000# trailer. Had a chance to tow it for the first time last weekend. My LC setup is currently stock (no lift, no re-gearing, and no armor). The trailer is 8' wide, 9' tall, and 23.5' long (including hitch), dual axle, and runs about 600# on the tongue. I run a WD hitch and a single anti-sway. When I pulled my trailer over the weekend I had a WiFi OBD2 reader attached and was running EngineLink to read the data. Here are my thoughts on towing with my setup... I know it's a 2013 but my results should generally apply to your setup as well.

Limiting to 4th (In the 2013, 4th is 1:1, IIRC in the 2016 it's 6th) I was cruising at 65-70 in mostly flat Illinois/Wisconsin (I-94) and ran around 2800RPMs +/-. I got ~10.5MPG at that speed (the instantaneous MPG reading from OBD2 was pretty steady between 10.2 and 10.8MPG). I tried running in 5th for a while but I found I had to lay into the gas pedal more to keep it at 65, so my gas mileage actually went down. Unless I was driving 55, using OD provided no MPG benefit.

I also watched the temps closely during the trip. Outside it was ~65F out. Intake temp was reading about ~90F (typical). My trailer was at the shop getting the bearings repacked so I drove about an hour to pick it up and then about an hour after I hitched up, thus I got some great comparison #'s:

• Without a trailer running in top gear (6th) the transmission pan temp reached 195F (+/- 1F degree), and the torque converter was anywhere from 195F (when fully locked) to about 208F (for instance when accelerating from 60-70). The higher TC temp didn't affect the pan temp much. Once the TC locked up again at ~70MPH the temps would both stablilze around 195F again.
• With the trailer running in 4th gear the pan temp stayed around 196F (+/-1F). Both the TC and the pan temp would read the same when cruising at 65MPH. About 2/3 of the way through the trip I tried running in 5th gear (first OD). The TC temp would climb (at one point it hit 213F) and the pan slowly climbed up to about 202F over the span of about 5 minutes before I put it back in 4th. At that point the temps slowly dropped down to 195F again. Also, I definitely noticed the weight of the trailer a LOT more when towing in 5th than in 4th.

In short, don't tow in overdrive - the gas mileage difference is small and OD generates heat in the transmission, especially if the ambient temps are warmer and/or you're pulling through hilly terrain. Yes if you're pulling a 2000# 4x5x8 uhaul trailer you can probably run in 5th or 6th without any damage, but if you're pulling a smaller trailer running in your 1:1 gear (6th in your case) will have less impact on your MPG than it does for me, so the $ savings is minimal.

As a side note, the weight of my gear (cooler, dog, etc) and family sinks my rear by about 1.5", and the trailer reduces another 3.5" (even with weight distribution running 4 links). I ordered a set of Firestone 4164 help air bags for the rear and an Air-lift compressor kit when I got back home on Sunday and am going to have my mechanic install them next week (I'd do it myself but I don't have a place to work on the truck except a cobblestone driveway that isn't completely flat - terrible for jack stands). I plan to write a full post on my towing experience in a couple weeks once they're installed and tested.

Those temperatures both with and without the trailer seem excessively high which makes me question the validity of the formulas used. My 4R transmission runs at exactly 80F over ambient when driving on the highway with the TC locked. I towed a 4k# uhaul trailer and was fully loaded with gear from NJ to IL in 85F weather and the fluid was still 80-90F over ambient.

I'm using a SGII to monitor both TC and pan temps FWIW.

 

[linuxgod]

I'm using the same sensors as SGII:

Toyota/Lexus/Scion Specific : Linear Logic : Home of the ScanGauge

It's possible the formula is wrong, though I've seen dozens of posts using that formula. I've also read that the LC has a thermostat in the AT line designed to get it up to operating temp. I haven't confirmed that (anyone has TIS access or an FSM handy?) but if true it would explain why it appears to run hotter.

I would be curious if anyone with a ScanGauge has hooked up to their LC to confirm/deny what highway temp they get.

 

[linuxgod]

The light comes on at 302F reading downstream of the TC.

That's good to know. If I ever see the light my fluid is already cooked!

 

[gaijin]

I've also read that the LC has a thermostat in the AT line designed to get it up to operating temp. I haven't confirmed that (anyone has TIS access or an FSM handy?) but if true it would explain why it appears to run hotter.

Not the best pic of the inline trans thermostat, just the best I could find:

HTH

 

[linuxgod]

I plan to write a full post on my towing experience in a couple weeks once they're installed and tested.

As promised, a full write-up at Towing with a 200-series Toyota Land Cruiser