Okay guys, here's a can of worms to open. Say I'm trailering my motorcycle to the track, total weight maybe 1000 lb. No big deal. I've got a 700R4 with 130000 miles on it and a Transgo reprogramming kit installed. This is on a Berlinetta with an LG4 engine. I've heard all kinds of people say that trailering causes an enormous heat buildup in the tranny, BUT...how does so much heat get built up when the TC is locked up on anything faster than about 45mph? Except for the added friction of the gears, what's there to cause heat buildup?

Let the discussion begin.....

 

simple it puts more stress on things, stress=friction=heat

btw

why on gods green earth are you towing anything with your camaro???? that is just wrong. but i guess if its all you got then there isn't much choice

sorry it just annoys me when people put hitches on sports cars,

the only time i thought it was ok was a vette i saw once, it had a small cargo trailer type thing, that looked like the back half of a vette, it was an older couple, (obviousley with money to burn) touring the country, i thought that one was kinda neat

 

Well, like I said, it's just a utility trailer with my sportbike on it. Which, btw, is a LOT more fun than the Berlinetta with a mostly stock motor. I guess if it had 350 hp it'd be different, but that's the way my priorities go. So it's either pull the trailer with the Camaro or pull it with my wife's 4 banger Celica. Hmmm, that's a tough decision.

As far as heat goes, I really don't think the extra 1000lb or so is going to build up that much heat just due to gears meshing together. I mean, how much heat does the differential generate? Almost none, and that's all it is is gears. That's probably the reason we don't cool our rear ends.

G.

 

As long as the torque converter is staying locked, you will probably be just fine. Yes towing causes heat, but a small trailer will probably be ok. Keep you eye on the temp guage, the tranny uses the radiator to keep cool--the heat will transfer to the coolant, then the engine if it gets hot. What I've seen kill a 700r4 while towing is using overdrive when the engine can't keep up. The tranny will then unlock/lock the converter quite often and upshift and downshift. If you feel the converter lock and unlock at highway speeds, use 3rd gear instead of overdrive. You have a much better chance of keeping the converter locked in 3rd gear.

 

Well, this is interesting. My tranny (with the Transgo kit) won't allow the TC to unlock in 4th gear. It always shifts 1-2-3 unlocked, then locks in 3rd, then shifts to 4th. I've never felt it unlock, even when floored. That's another thing about the kit is that above 60 mph it won't downshift to 3rd automatically. Yes, the Tv cable is adjusted correctly. Either I installed the Transgo kit wrong or that's the way the kit is. I dunno.

G

 

I may be able to shed some light.

I have heard of problems in GM OD transmissions when towing in OD. I believe the specific tranny I was reading about was the 4L80E, don't remember a year specific. Apparently, when in OD, ATF is bypassd from going through the tranny cooler. If these trannys are set up to unlock the converter but remain in OD under certain parameters I can certainly see potential to really heat things up.
People have complained of shifting problems, I believe, when this occurs. If I remember correctly they have a tranny temp sensor that sends a signal for some normal occurrence to not occur until the tranny temp has dropped, in an effort to save the tranny from ultimate destruction I am guessing.

I have dragged 4000 lbs behind an Explorer V6(tow package including tranny cooler and 3.73 gear) on two occasions, both involving fairly steep freeway grades. I may be wrong, but I have not perceived an unlocking of the converter when the tranny has been in OD, no matter the load or throttle opening. When in Drive it will lock and unlock at will.

Someone above mentioned the fact that while towing engine coolant temp may rise and with a water to oil cooler, this would undoubtedly result in higher ATF temps. THe Explorer runs cold under most conditions but while towing has run in the high end of normal under prolonged near full throttle loads at 30-60 mph. When this happens I have noticed a tendancy for the tranny to feel like it slips a bit when shifting. I am guessing this is because the tranny temp is elevated to its highest even though the cooler is an air to oil in front of but flush with the radiator. My guess is, higher ATF temps might reduce line pressure and cause other friction related problems that could cause slipping. When the tranny has cooled down this slipping goes away and the shift returns to a 'mild firmness' it has had since brand new. It has 130,000 miles on it with no repairs and gets regular fluid changes using a simple drain plug and refill with 4 qts of conventional ATF method.

I would like to hear one of the board's auto tranny experts to shed some light on this subject if possible.

 

In a stock configuration, the tranny will lock in 3rd gear. My 82 won't lock in third gear because of the TCI 'no-computer' kit. But I can add an additional toggle switch to force a lock-up--which I would do if I had to pull something in 3rd gear.