My Troop started shuddering and grinding accelerating from a stop while towing last week. A looked underneath found ATF fluid all over the bottom of the Trooper. I pulled off the road and it would not even move again once I got in some grass.

After putting in the one quart of ATF I had on hand, it would move again. I took 3-4 more quarts to fill it up (filled with the engine running). I put the Sammi on a buddies trailer on the way home, and the Troop has been driving fine since adding the fluid.

What do you think happened? Did the trans just overheat and puke fluid somehow? Is this possible? Or have I likely blown a seal/gasket?

I think the Trooper already has a trans cooler. Should I get a bigger/better one? I was only towing 2500 lbs.

<small>[ April 15, 2003, 11:11 AM: Message edited by: JimShrake ]</small>

Weird...Troopers have the standard line through the radiator, that serves to preheat and cool the fluid depending on which fluid is hotter at the time. There is also an AT Temp idiot light, I believe. That didn't light up, I take it?

Info I have read says that heat-related failures on the 4L30E are rare. That didn't stop me from putting a tranny cooler on mine, though.

One stray thought: Did you get water in the fluid (do any fording lately)? Maybe if the fluid had water in it and got hot enough the water would expand and force its way out the breather (this is just a brainstorm on my part, not sure if it can even happen that way).

The "Check Trans" light did come on once.

I actually finished the towing to hwhere I was headed after noticing the problem before doing anything about it. I was almost there where I first noticed it. This was after about 4 hrs of towing.

The next day I got in it to drive about 7-8miles and the symptoms were the same or worse with the tranny cooled off and w/o towing anything. About 5 miles down the road the "check trans" light came on for the first time.

I went a few more miles to get where I was going, then added the quart of fluid before moving it again. That helped a lot.

I'm not sure if the check trans light means low fluid or overheated or possibly either. It never came on during the long towing trip, and it seems hard to believe it over-heated in five miles w/o towing.

Either way, it sure seems like the light should have come on the previous day while I was towing. <img border="0" title="" alt="[Confused]" src="images/icons/confused.gif" />

</font><blockquote><font size="1" face="Verdana, Tahoma, Arial, Helv, Helvetica, Sans">quote:</font><hr /><font size="2" face="Verdana, Tahoma, Arial, Helv, Helvetica, Sans">Originally posted by JimShrake:
<strong>What do you think happened? Did the trans just overheat and puke fluid somehow? Is this possible? Or have I likely blown a seal/gasket?</strong></font><hr /></blockquote><font size="2" face="Verdana, Tahoma, Arial, Helv, Helvetica, Sans">When the tranny gets hot it dumps heat into the radiator, so if you had serious transmission overheating you would probably also see your car's temperature rise. I have certainly seen this happen when off-roading and overheating the transmission (thus my tranny cooler) but at highway speeds I think it's possible the radiator would be able to stay cool. Not sure.

The AT Temp light is separate from the Check Trans light. I'm guessing the CT light went on due to low fluid level...why the fluid went spewing out of the tranny is still a mystery.

the check A/T light will produce a code just like check engine light. You can go to Autozone and have them pull the codes for you. My Amigo seems like its unhappy pulling long distances lately, 3 times it has set of the check light while flat towing more than an hour or so. 1st time the code was "slipping.....". I plan on doing a fluid and filter change this weekend.

How hard is it for a DIY to install a trans cooler? I'm still in the process of "thinking" about a boat (3500-4000 pounds) and don't want any surprises while heading to the lake <img border="0" title="" alt="[Big Grin]" src="images/icons/grin.gif" />

It's pretty easy. The tranny already has a cooling line to the radiator, so it is just a matter of hooking up to that line, and finding a decent way to mount the cooler. Most people I talked to didn't think much of the zip-tie-through-the-radiator mounting system that comes with most tranny coolers.

Jim: At uwharrie, Rubo's rodeo acted similarly. Rubo had made several hard runs at Rocky Mount, then we noticed ATF on the ground. Shortly later, his A/t light illuminated. Within minutes, his tranny was gone. HE let engine sit and tranny came back. Later that night, he was back in business.

Well I noticed today that there are separtae light for "check trans" and "trans temp".

Thanks for the info guys. I think I'm gonna get a big ass cooler. <img border="0" title="" alt="[Smile]" src="images/icons/smile.gif" />