Tranny "falling" out of gear when hot.....

[SHOfun 93]

Well this is twice this has happened in the past month or so. I went to the track tonight, and the SHO shifted like a champ all night, no burnouts, and seemed fine. On the drive home ( the track is about 20 miles from my house) the SHO started to buck, lose gear, and only shift into 2nd at the highest. I pulled over and fortunately a friend who was at the track saw me and followed me into town as I just kept it in 2nd on the shifter to prevent it from trying to shift into 3rd and slip in and out. I thought for sure this time the tranny has let go. However, when the tranny cooled a bit, it shifted up into 3rd and then I was able to drive it home at a better rate. I babied it home and let it sit, pondering wether to even trailer it back to Dallas (again) or to keep on driving and bite the bullet for a Doug Lewis special.

Three hours later, after doing a lot of thinking, I decided to see how she was shifting. I got out of bed, went out to the car started her up and wanted to see if I could even get something up to 3rd for using around town. I checked the tranny fluid, it had a burnt smell, but stil appeared a nice red color, not black. Hmmmm oh well, I might as well see if it will shift worth a dang, so just a bit ago, I took her for a spin and was pleasantly surprised that the car shifted like a CHAMP! IT EVEN FOUND OD! I got brave and really got on it from a stop and it found all the gears like clockwork!

Here's my question. Can the tranny fluid get so hot, that it loses viscosity to the point where it won't shift? To the point where after it cools, it shifts again? If there was gear damage, or if the OD band was shot, it wouldn't be able to find it again, (trust me I know) but my buddy said that there wasn't any black smoke following me (that is what happened the last 2 times I dropped trannys) and all it did was slip and slide around trying to find gears. After cooling, it shifted fine again. Should I flush and switch to synthetic to be more temperature stable? Some have said that a flush will send the tranny out the door for good, but if there was indeed gear damage, it wouldn't be shifting as good as it does now. I think it just needs some more temperature stable lubrication. Let me know what you guys think..

<small>[ August 04, 2002, 04:10 AM: Message edited by: Jeremy Hohn ]</small>

 

[luigisho]

Do you have a tranny cooler? The trannys are bad enough and add Texas heat. I'm no tranny pro but a tranny cooler with a modified tranny to get better fluid flow might pay for itself and then some over time. Just my $.02.

By the way wasn't there a tsb for upgrading the pcm for '93's with shifting problems? Also I thought the internals on that tranny were weak and were replaced with harder metals.

<small>[ August 04, 2002, 11:08 AM: Message edited by: luigisho ]</small>

 

[Mr Anonymous]

Yeah, ATF fluid can boil given the right circumstances (which it sounds like you had). A synthetic ATF would definitely help, but if you don't have an external cooler, you should consider adding one, and if you do have one, you might want to check the flow rate. Aftermarket external coolers are relatively cheap.

I'm one of those who doesn't buy the idea that a flush accelerates tranny failure. The main problem I find is pan leaks after a flush. They are are common enough that a re-torque of the pan bolts in a few days along with verifying proper fluid level are prudent to avoid low-fluid related failures.

 

[SHOfun 93]

I have a hayden 26 cooler, but I was running run after run at the track last night and repeated WOT runs will get the tranny hot quick. Under regular driving conditions, it does fine. I think I am going to flush and add synthetic soon. Thanks guys. By the way, how would I go about checking the flow of the Hayden?

Also I have read of ways to flush the tranny by disconnecting one of the lines to the cooler and add new fluid through the tranny fluid dipstick. That way I don't have to worry about dropping the pan at all..however I plan on adding a tranny temp gauge and I will have to drop the pan anyways..

<small>[ August 04, 2002, 12:36 PM: Message edited by: Jeremy Hohn ]</small>

 

[hooterville]

My advice, DON'T RACE IT! Just my $.02.

 

[SHOfun 93]

 

[Mr Anonymous]

There's a procedure to measure flow rate, I'll see if I can dig it up and post it for you.

As to flushing, it's still a good idea to drop the pan to check the magnet for any really bad news.

 

[Sho-N-Go]

also jeremy that cooler wont cool very well sitting still. I believe those help more when the car is moving

 

[SHOfun 93]

I plan on dropping and switching pans to one that has a tapped hole for my tranny temp gauge. I agree toolboy, that the fact I was running hard, and then parking, helped the motor cool, but the tranny remained hot. I will be dropping the pan this month, and investigating further when I add my tranny temp gauge.