Just lost the trans today...

[gman4dx266]

So i drove to class today, parked nose-to-nose in a spot, came out after class, and the truck wont go into reverse. Its like theres a stake right thru the Ujoint into the ground. Just a -jerk- when you pull it down to R. Neutral was now a 'forward gear'(the same as D) and 3,2 and 1 were still the same. I managed to push it out of the spot, ignition off and in N, and then tried to drive it home. Thats where i came to another problem. It wouldnt upshift from 1st > 2nd. you would have to play with the throttle to get to 2600 revs, then let off to decelerate to 2500 for it to 'drop' into 2nd. We wont even talk about downshifts on hills...

So its in for some work as we speak. Looks like she'll be sitting in another garage for the next few nights. Anyone know what could have went ka-put?

Anyways, Keep the M30 in your prayers.

[gman4dx266]

Well, i finally got my truck back from having the trans rebuilt. They sure took thier time on it, thats for sure. Anyways, heres the receipt they gave me.

[PurplePiss]

There aren't supposed to be melted together? :lol:

[gman4dx266]

There aren't supposed to be melted together? :lol:

Yeah...if they werent together, how is power transferred?

[eficalibrator]

Did you have the torque reduction turned off in the tune? Any additional (or even stock) trans cooler?

[v i k i ng]

Did you have the torque reduction turned off in the tune? Any additional (or even stock) trans cooler?

is turning off torque reduction bad ?
what setting do you recommend ? ( stock)
my trans temp follows the motor temp by a few degrees ? what is the temp trans should be ? do you recommend an external cooler also ?

[gman4dx266]

I dont have the extra cooling jazz, just the regular line that runs thru the radiator. I was running with my TM 0'd out, cuz i figured, its a dinky 6 cyl, so what the hell.

Now i dont have any trans temp gauges, but i -do- monitor fluid temp, even though it makes -zero- sense to me, when it tells me 'transmission hot' on my DIC when the fluid gets to 120F. I mean...other peoples trucks with transcoolers and temp gauges, read ~210 on a typical day, and light driving. So i need some answers as well.

[eficalibrator]

Guys, please keep in mind a couple of things.

1) Transmissions are rated for TORQUE, not HP.
2) The amount of torque that a trans can handle when the clutches are less than 100% engaged is significantly less than when you are locked into a single gear. Even "only a 6 cyl" can make more torque than this at WOT.
3) OEM clutches have less torque capacity that aftermarket "performance" clutches
4) When the clutch slips, that friction generates heat. Even if it's only local to the clutch pack, it's still heat that may reduce the already compromised torque capacity of the friction materials.
5) Torque reduction requests during a shift are specifically engineered to preserve transmission life.
6) A single fluid tube running through a radiator end tank is most likely not sufficient cooling for a trans being used in a performance application. It's most likely just enough to cool it under "normal" conditions. You racing the truck with increased engine torque and decreased (or deleted!) torque reduction during the shift (when the clutch packs are already slipping a little bit) only makes this worse. Get a real cooler if you intend to abuse it. If nothing else, the "trailer towing" cooler from the OEM is at least a step in the right direction. It's not like they're expensive, especially compared to a rebuild!

Are you sure you're not reading 120 degrees C instead of F? Are you sure where this temperature is taken? It's very possible that you are looking at a modeled temp instead of a measured temp as well.

Unfortunately, this thread appears to be a case of completely predictable results from deleting TQ management. I used to see this all the time from the F-car guys years ago.

In my calibrations, I typically reduce TQ reduction by about 20%, but don't eliminate it. Better results often come from reducing target shift time (to a minimum of ~0.200 sec) slightly as well. If you really want harder shifts reliably, it's time for a hardware change inside the trans. At that point, set it on kill with the H/W and soften up the low TPS shift firmness in the calibration to make it more comfortable off throttle.

Moral of the story is: Do not attempt an electronic solution to a mechanical problem.

[gman4dx266]

Thanks for the info. Im aware that trans' are rated for tq, even so, my 6 cyl only has about 260ft lbs(at best). Without a performance rebuild, is there a setting i could change(FMC perhaps?) that would apply the clutch packs and hold them until X event/threshold is met?

As for the temp, in the scanner i monitor "Trans Fluid Temp (*F)"

So, yes its Fahrenheit, but no, i dont know if its modeled, or an actual measurement. It just cant be right though, because to me, 120 seems much too peachy for trans temp. Maybe 220 but not 120.

[EC_Tune]

Also, they build the V6 transmissions differently (more lightly) than the V8's. Way back when I had a trans guy tell me they used less clutch packs in the 700 R4 for the V6 applications compared to the V8. Cost savings was the main reason.

Not 100% sure if they still do this but GM is run by bean counters...

[gman4dx266]

You know, EC_Tune, i think you have something there. I stopped by the shop when it was a 'work in progress' and he was sticking the clutch plates/packs, and there was only 3 of each, that i counted. (I thought there were more in a beefed up trans). I also walked over to the "shell" of the whole thing, that was hanging open-end-up on a holder to drain the ATF out, and i couldnt believe how small the planetary gearset gears were. The ones along the outside were only as big around as my thumb(or there-about)

So, sure i would believe it. They should call mine a 4L60-E-6, and the ones for the 8-sparks 4L60-E-8. They're misleading you to think "sure im getting the same trans as XXX engine/vehicle"

[v i k i ng]

The last scan I did I did a PID for trans temp. My trans temp followed my engine temp within a few degrees. That was an answered question I asked on another forum, ...are the V6 trans weaker than what i remeber V8 auto trans from HS days. A friend of mine had a Torino that he use to hammer the trans. I think once I could smell the clutches burning, ,, it is something i would not do,,,, although the car kept running.

[gman4dx266]

I too stick the trans temp PID in my scans, but its always off on some goofy #, wich seems like its 100* shy of the real temp. Could it be that i dont have a -real- temp sensor. I would think fluid temp would be pretty close to trans temp.

You guys are right though, its gotta be somewhere around 198, since thats basically where my engine temp stays. (no matter if its light driving or completely hammering it...go figure)

Everything today is about cost. When i get enough "spare cash", i hear that you can beef up an 'L60 for fairly cheap; thats probably what ill do.

Until then, for the next 29K miles...the warranty is my friend.