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Transmission Question

ken1mod

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ken1mod Senior Enthusiast

ken1mod

Posted
Posted

Gentlemen,

 

Is it OK to drive all day in a gear lower than Hi gear, whichever that is? I guess my question is are all gears in our automatics rated for continuous duty?

 

Specifically, is 4th gear on the six speed ok to use all day in towing conditions?

 

Ken

KMGZ400 Senior Enthusiast

KMGZ400

Posted
Posted

i dont think it really matters... the only thing that bad is if you have it in 2 and are near redlining it... i shift gears around all the time and drop it into 2 for hills and stuff like that. what else could it be meant for?

nickvrebel Senior Enthusiast

nickvrebel

Posted
Posted

it shouldn't cause any problems, just keep an eye on the transmission temp.

 

Personally I don't see any need for it when you can just throw it in drive, press "Tow/Haul" and let the automatic transmission pick they gear based on GM engineer's programming... but that's just opinion.

music Senior Enthusiast

music

Posted
Posted

In short, yes. Generally, for higher weights and/or drag, 4th on the 5.3/6-spd is a good hwy towing gear and 3rd becomes the first "climbing gear". 3rd is the main hwy "tow gear" on the 4-spd, where 2nd is the main climbing gear.

 

On the 4-spd, if you're towing in 3rd and climb a grade, the TC unlocks first... boosting rpms by ~10 to 15%. If that's not enough, it downshifts to 2nd w/ TC unlocked, boosting power another 40+%, but I don't think the TC locks (?). At high rpms, there isn't much TC slip anyhow, but it does seem to add some heat. From what little I gathered a while back, the 6-spd will try to lock the TC ASAP, and will downshift rather than try an "unlocked TC" position. For example, pulling in 4th, the 6-spd will probably go straight to 3rd and lock rather than try an unlocked 4th position. Unlocking the TC may boost power by ~300 rpm, but downshifting may only be 600 rpms to 3rd... so it just goes to the next gear. Doing so keeps the TC from running unlocked, and thereby helps reduce heat.

 

Don't rest your hat on the above examples, as it's just some info I gathered earlier this year. I don't drive/tow w/ a 6-spd, so I can't confirm the operation. It doesn't matter, as the answer to your question was simply "yes".

Rat4go Enthusiast

Rat4go

Posted
Posted
Gentlemen,

 

Is it OK to drive all day in a gear lower than Hi gear, whichever that is? I guess my question is are all gears in our automatics rated for continuous duty?

 

Specifically, is 4th gear on the six speed ok to use all day in towing conditions?

 

Ken

 

 

Like others have said....if you're NOT revving the snot out of the motor (say 4000 rpm or greater) for extended periods of time (say 20 min or more), then you're fine for both the trans and the motor. From what I've gathered, it looks like the converter locks in a 6-speed in 4th, 5th, and 6th even if you're not in T/H, so trans temps shouldn't be an issue. Higher rpm usually brings engine temps up, though. Worth watching, but probably not going to be an issue.

 

Running in M4 eliminates the grade braking stuff that works in Tow-Haul, however...that's some cool stuff when towing in the mountains!

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