Recently supercharged I have become concerned about blowing up my 5AT transmission, and I am curious where the greatest tranny stress occurs during WOT operation. I'm not "racing" and have no need for the 'best times,' but enjoy experiencing the exhilarating pulls at WOT.

I have been in the habit of ripping through a gear and letting off the throttle during the shift (manual mode) until the tranny has found the next gear, then 'putting the hammer back down'... and repeat. Timing is key to having it fall into gear without hearing the torque converter slip. I notice if my foot is on the throttle (during the shift) even a tiny bit, or I'm back on the throttle too soon (before RPMs are matched to the next gear), it will delay the shift and the torque converter is inevitably used. Really, I'm trying to ease the life of my tranny, and I am assuming the torque converter is pretty much behaves as an electronically controlled clutch? (BEHAVIOR wise, I am aware it's not built like one at all).

From outside the vehicle, it would appear as if I have a manual tranny and a slow shifting ability... but it feels easier on the tranny.

What do you guys think. Will my shifting habits prolong the life of my tranny? It must greatly reduce the wear on my clutch packs, right?

(Excluding Tranny Temperature issues)

Thanks!

 

Wow, the response is overwhelming. I'll have to take the day off work to review all these comments!

Anybody?.... buehler?... buehler?... buehler?....

 

I think WOT w/ an extra 100 or so hp, is stressing the clutch bands and heating them up when they are slipping. But because no TCM altering logic is available at this time, we are limited to mechanical fixes tranny-wise. IMHO one of the things you can do is get a valve body modification done. It won't change when the tranny shifts but it will up the line pressure and make each shift FIRMER and with less slip. That will help make the tranny live.

And hopefully since the shift itself will take less time, you won't be running into the rev limiter before the tranny decides to shift. (if that's one of your issues). I was on my buddies auto SC'd maxima

 

The transmission commands the oem ecu to zero ignition advance [power cut] just before, during , and ramps back up when complete.

The tranny has a 333 lb/ft shaft input limit for 100,000 shift cycle life.

 

I just added an external cooler on mines and when I go WOT I release it a bit so it can shift and then I get back down on it

 

Think of each shift cylcle as costing 4 cents and save that amount [$45] monthly from day one and you will have the replacement cost on hand with interest.

 

100,000 cycle... is a cycle 1st thru 5th at normal throttle/acceleration? With 100,000km on my vehicle, should I start saving up for a tranny? How much is a new tranny (about)?

 

SGP has a beefed up one for $2,995 with core exchange. It will cost a few hours labour to make the switch.

 

As a minimum, get a trans cooler. The more quick launches you do, the more stress on the fluid, causing it to break down. By adding a cooler, this will help slow down the shearing of the fluid. I also change my fluid about every 15K miles to insure good fluid, which helps insure good value pressure.

I also had the trans re-worked by Stillen to handle the addition stress.

 

Valve body upgrade?

 

That's good info, I'll look into it.

Thx Slider