transmission question about hauling heavy

[rlebar]

Buying an 03 SCSB 4x4 on Monday. I need to haul close to 9k behind it for 1300 miles. I know different transmissions respond differently to towing. If I understand correctly, it's got a 4r100 under there.

While towing, should I lock it out of OD? or just make sure it's not being lugged in the low rpms? I don't want to burn it up on it's maiden voyage because I'm ignorant to how to treat it

[Hank]

I'm no expert but I would lock it out of OD. Got a temp gauge on it? If not you can add one very easily in the test port on the driver side of the tranny. That way you can watch it.

[rlebar]

yup it has a temp gauge.

And that's one nice truck you got there

[Hank]

Originally Posted by rlebar

yup it has a temp gauge.

And that's one nice truck you got there

Thank you sir. Watch the temp carefully. I removed my front license plate holder and dropped my temps a bit. I have since added a second stock cooler and it runs real cool now. Just know that you can pull over, buy a universal cooler and cut it in to your hoses and increase your cooling capacity if you have to. Better than burning up a tranny. They are expensive to repair/rebuild. Believe me I know! And so do a lot of my friends on here.

[NoRalPh]

I wouldn't rely too much on the factory gauge.......

Most modern instrument clusters use what's called idiot gauges. That is, the gauge is run by information interpreted by the PCM.

I guess, to instill confidence in their customers and limit service concerns, it's just easier to make most gauges sit their needles right smack in the middle of the range. So, what you have is a Wide Range of actual temps & pressures that end-up showing "normal" readings.

Only when Very Low/High will you see any deflection from that, magic, middle

And of course, what this does, is to eliminate you from seeing an early indication of trouble

[rlebar]

Originally Posted by NoRalPh

I wouldn't rely too much on the factory gauge.......

Most modern instrument clusters use what's called idiot gauges. That is, the gauge is run by information interpreted by the PCM.

I guess, to instill confidence in their customers and limit service concerns, it's just easier to make most gauges sit their needles right smack in the middle of the range. So, what you have is a Wide Range of actual temps & pressures that end-up showing "normal" readings.

Only when Very Low/High will you see any deflection from that, magic, middle

And of course, what this does, is to eliminate you from seeing an early indication of trouble

I didn't even know the truck had an idiot light for the trans temp.

The truck actually has a boost, pyro and trans temp gauges, so it'll be good from that end of things.

[NoRalPh]

Originally Posted by rlebar

I didn't even know the truck had an idiot light for the trans temp.

No, no, it doesn't... I was talking about the factory gauge. I didn't realize you have something other than the stock gauges

[mxfever090]

When I'm pulling heavy I turn OD off under 60-65 mph. Once up to speed on the highway and rolling 65 + I let it go into OD and feather the throttle on hills to keep it from shifting. I don't have any aftermarket trans temp gauges but I watch the factory sweeper like a hawk. When I finally do get gauges trans temp will be top on the list.

[dmd]

If it is all stock then just run in OD, it will shift out for you when needed. Mine
shifted out way to often at any slight hill and I tow about the weight you will be. I
hated it when running stock, anything more than 65 and it was really working. Now
it goes 70 and just sings along. If you add power, get a valve body, better TC, and
a larger cooler so the trans lasts longer (what I should have done).

OH, if it keeps shifting in and out of OD, just lock it out until the road smooths out.

[dieselcrawler]

If it's holding a gear, and temps on your aftermarket gauge is below 200, you're fine. If it's shifting up/down alot, and temps are over 200, time to change something... lock out OD, slow down, something...

I have found that out on the open road, I don't have any temp issues... it's the local hills and back roads that take a toll on my trans... I can pull an empty 12' box trailer around these hills, and the trans gets to 220 quickly... loaded equipment trailer, 3 times the weight, and on open flat roads, will stay below 200 easy. Stop and go is hard on them too... anytime the tork converter isn't locked, and it's going thru the gears, the trans is creating heat. So, just drive smart, keep an eye on the trans gauge.