I fianally got to tow with my suburban. I towed my camper, I have a 31' bunkhouse weighs 7200lbs empty. Loaded it up and my family in the suburban. Can't forget the dog here. I have 4 kids and the wife and all the stuff for a good weekend of camping.

I towed about 170 miles one way through some hilly areas and some flat areas. Engine temps stayed around 190 degrees, boost running about 5psi and trans temp about 195 degrees and EGT running about 700 degrees. This is at 55 mph and about 1800 rpms. I pulled in overdrive as I had just done the TCC mod.

I had a couple of opportunities to pull some longer hills and played with it a bit. Watched the EGT spike 10 about 1100 degrees and boost would max around 8 psi. Let off the throttle and EGT settle right back down. I only had a couple of issues, when idling through towns around 25-35 mph the trans temps would climb quickly. I started putting the trans in neutral to see if that would help, as soon as I could move fast enough I would lock the torque converter and it would cool down pretty quick. Does this sound normal? I had just changed the trans fluid and filter. Levels are all OK.

I like the way the vehicle towed, have to admit more power would be nice but it held 55mph on hills and dropped about 4 mph on the longer ones with the cruise on. I figure we were around 11-12 MPG.

I tried a stretch of interstate for about 20 miles and 65 was just too much. I watched the fuel level drop faster than normal. It held 65 with the cruise on, I even had to brake for a semi on a hill.

Any thoughts on the trans temps?

Thanks
Theront

When the converter is not locked up it will run hotter. In my T/A I can watch my temps go up to around 220 when i'm driving through town. But when I can get up to around 60 where I can lock it up(huge cam) then it will come back down to around 190. So I would have to say it's normal IMO.

Nice, Theront! Sounds like your mods worked out for ya!

Tranny temp... when you're going slower, make sure you unlock the TCC. The trans will heat up more in town, with a load on the back. You can fight this a couple of ways...

(a) put on a high-capacity tranny pan. They hold an extra 3-4 qt of fluid, which acts as a heat storage reservoir and delays heating-up in towns. The good ones also have cooling tubes through them.

(b) mount an auxilliary trans cooler under the body, with a temp-switched electric fan on it. When the temp of the fluid goes over the switch threshold, that will add cooling capacity. Buddy of mine has one on his, and his temps never go over 190*. Ever.

Glad your 'burb pulls so well.. just remember it's a 6.5, not a Kenworth, and you'll get many happy miles out of her... just take what the truck has to give and be happy.

You still need to pull the snorkle to let air in, and change out the exhaust ('94s are prone to crossover collapse) to let exhaust out... both of which will give you more power and better mileage.

Now... that being said, if you REALLY want to love the truck, get an HPT chip and Turbomaster from Heath. It will take a month to get the stupid grin off your face.

I pulled one summer with mine basically stock; it did OK, but ...

Then I found this site. Inside of a year, I did intake, exhaust, PMD isolator, Turbo-master, Max-e-tork chip, and life hasn't been the same since. I think if I had left it stock, I would have gotten rid of it long before now.

Just a heads up on the trans cooler with the tubes through them. They tend to plug with oil, then dirt/mud and out where I live grasshoppers and other critters. When this happens no air flow. Personal experience here.

Regards, Jeff

How hot did it get when you went thru town? When I got my trans temp gage I was wondering how hot is too hot so I took a look at my dad's d-max factory trans temp gage. The red mark is at 300f. I also know that engine oil temps run up near 300. I don't think 200f or 250f is a problem especially if it only occurs briefly while slowing down to pass thru a small town. just my $.02.

I saw just over 250 for a couple of minutes, then I managed to get moving good enought that I could lock up the converter. this cools it down relatively quickly, like withing 3-5 minutes. If I can get moving on the highway I can cool it down even quicker. My problem just seems to be in town like from light to light. We were pulling in Wisconsin Dells area and it is fairly hilly. I started to put in neutral while waiting at lights.

I would go for more power upgrades but I don't want to destroy the head gaskets again. When I did them the block was pitted, so I used JB weld to bring the low spots up and the head gaskets I found has a metal reinforcing plate from the end cylinders and around the coolant passages. I am just thinking that more power would cause damage with my current set up.



I did just prior to the trip remove the cat and installed a 3" Cherry Bomb muffler. We like the way it sounds kind of deep and throaty.


Thanks

It's building heat in the towns for two reasons. One with the torque converter out of lockup you are driving the truck using two fans in oil. This creates allot of heat in the oil. Two the only time that the oil in the torque converter circulates thru the trans cooler is when it is in lockup. This causes the heat to be trapped in the trans and build up quickly. I haven't gotten the torque converter lockup mod done on mine yet but after hearing your experience I am definitely going to get it done before I town my big trailer this summer. If my trans. temp behaves like yours is I will be happy the results and will leave it as is.