Hey guysI'm new to towing a camper. We have a 24' tt dry weight 4500#. I just found out we have the gt4 (3.73) gear ratio on our tv. We have put a transmission cooler on the vehicle to cool it down but it still runs over 250 on the interstate. On our last trip I got a little more comfortable with towing the camper and I got up to 70 mph. After about 15 miles the transmission warning came on. I was wondering if anyone might know of anything else I might try. We have looked at 3/4 ton trucks but we cannot find one that fits our needs and budget. LolI thought about replacing the rear gears with the 4.10 but didn't know if that would create a whole new set of problems. Any suggestions would be greatly appreciated.

Btw this is on flat terrain. Thanks

Good morning and Welcome to the forums! Glad you are here and I hope you get all your questions answered. We have a whole bunch of very informed and helpful folks here.If you have not done so, you might check out our Forum FAQ. There is a ton of information that may help you as you get into the RV lifestyle. Also we have a couple of sticky threads at the top of this forum that would probably help you out. Give them a look.:)It would help a lot if you were to fill out the signature portion of your profile. The members can not give you accurate or helpful information without knowing something about your tow vehicle. At the very least please put that information into a post soon on your thread. You won't get much help until you do.Once again, welcome and please come back and post often.:)Barney

Thanks! I put it in the subject line. But I guess in the post would be better. It's a 2007 Suburban Z71.

The best place is in the signature. That is where everybody looks first and it will show up on every page that you post on. Often, people post questions or answers to a question and it helps a lot to be able to look at their signature to see where they are coming from with their answer.Edit: Perfect example is the post just below this one. Thank you jsteih for your perfect timing! :BBarney

My 02 silverado would run about 210* in stop and go, and 195* at 65mph on the interstate. I had the stock cooler, and I installed a Trucool 40k on mine and now it runs 155* all the time, the most I've saw was 175*.Check out this, I have no affiliation with him, but I installled mine with his kit. Should fit your 2007. It will help with the install. It was really easy. http://www.performancetrucks.net/forums/member-made-tools-parts-classifieds-197/tru-cool-max-trans-cooler-4739-47391-install-kit-brackets-fittings-hardware-508374/

2007 Suburban Z71 towing question | Good Sam Community

29 Replies

Jpedigo
Explorer
Aug 16, 2016
Thanks. I will have to get that checked.
Turtle_n_Peeps
Explorer
Aug 16, 2016
You have a mechanical problem.

I don't care what gear you have it in; whether you have it in OD or not; whether your fan is working or not............something is seriously wrong with your cooling stack or transmission.

No way, no how should a tranny get that hot on a flat road towing that load at that speed.

At 65 or 70 MPH on a flat road you don't even need a fan.

Don't let anybody on this forum tell you that your driving your TV wrong. You need to get your TV to a trusted mechanic that knows what they are doing with transmission cooling problems.
Grit_dog
Navigator
Aug 16, 2016
Jpedigo wrote:
I think I need to just slow down. I normally drive between 58 and 65 so I am probably working that tc. I did read the owners manual and it said I can tow in 3rd. I may try that to see if it lowers the transmission temp.

There's no may about it. If you were dogging it in 4th/OD then it ran considerably hotter than if you were in 3rd with enough power to keep the converter from unlocking.
I think you'll be fine with your setup although additional fluid capacity and cooling will help a bunch as well. Have to remember the limits of what yer driving. You're not going to be able to keep up with the HD/diesel crowd with a 10 year old half ton.
Good luck, btw always like the Z71 models. They're cool!
Jpedigo
Explorer
Aug 16, 2016
I think I need to just slow down. I normally drive between 58 and 65 so I am probably working that tc. I did read the owners manual and it said I can tow in 3rd. I may try that to see if it lowers the transmission temp.
jsteih
Explorer
Aug 16, 2016
GWolfe wrote:
The tow/haul will not take it out of overdrive if you have the 4 speed transmission, you will have to put the gear selector in 3rd yourself. At least my 04 was that way.

This is wrong. If you are running tow/haul mode on a 4L60E, it will hold third gear locked up until you get over 63MPH. Then it will shift to 4th with the TC locked, if you increase RPM enough to unlock the TC it will automatically shift to 3rd gear.
Grit_dog
Navigator
Aug 16, 2016
Ya try towing again and make sure it's locked in drive/3rd gear and check the temp.
Letting the engine wind up is better than bogging the trans and final drive ratio down.
It won't be first up the hills but no reason that rig shouldn't to be able to tow 6klbs in the flats without issue.

Other not horrendously expensive mods if still running too warm and you don't have another obvious issue is deep trans pan with cooling fins, second trans cooler if you can get it plumbed in somewhere.
Jpedigo
Explorer
Aug 16, 2016
Well I am definitely learning some things I didn't know.
APT
Explorer
Aug 16, 2016
Tow/haul trans mode and lock out 4th/OD when towing any high walled RV. You'll want to spend all your time >2000rpm, closer to 2500/3000 is better. You'll actually have better throttle response, lower trans temps, and likely use less fuel.
Terryallan
Explorer II
Aug 15, 2016
Thing is. Running in a lower gear (5th or 4th. This will turn more RPM causing the fluid to flow more, and so keep it cooler.

And BTW. Your tires are only rated for 65 MPH
GWolfe
Explorer
Aug 15, 2016
The tow/haul will not take it out of overdrive if you have the 4 speed transmission, you will have to put the gear selector in 3rd yourself. At least my 04 was that way.