Transmission Peak HP

[BubbaTheHut]

I was wondering if anyone had an idea on exactly how much power the 3400 tranny (Tblablabla) could take. And what are some preventive measures people are taking to make shure their transmission lasts with added hp.

[timka86]

i'm sure this has been covered. cooling is the big issue. keep it cool and it'll last longer. so get a trans cooler. they're sold everywhere, almost the same price, and i forget the brand, even though i have it, it has a lifetime warranty too.

[LoboMan7409]

i'm sure this has been covered. cooling is the big issue. keep it cool and it'll last longer. so get a trans cooler. they're sold everywhere, almost the same price, and i forget the brand, even though i have it, it has a lifetime warranty too.

So does your trani cooler really work?

[AaronGTR]

Mine works. First time I installed one tranny temps dropped about 30 degrees. I have a larger one now.



We don't have a real definite answer on how much power the 4T45E can handle. It is generally acknowledged that over the 200whp mark it will start wearing faster, and a cooler will only prolong this a little. There isn't much you can do to make them last longer without opening it up for a comprehensive rebuild. First thing to go is the clutch plates since they weren't meant to hold that much torque. There's lots more info on this if you search. Pretty much though, no one with a built 4T45 has broken theirs yet, so we'll have to wait and see.

[iceman]

Maximum Engine Torque
4T40-E 270 N·m (200 lb ft)

4T45-E 290 N·m (215 lb ft)

Maximum Shift Speed
1-2 6,500 RPM

2-3 6,500 RPM

3-4 6,500 RPM

this is from the trans specs, so anything over max will start to wear it down

[SikMindz]

Out of curiousity, do we know of anyone who has actually detonated they're trans b/c of excessive power? Or is still something we *think* will happen pushing the limits?

[BubbaTheHut]

Thanx for your help!! I assumed trans cooler i just wasnt shure if people where doing internal trans work to make them stronger.


Another HP related question, i read that injector fatigue starts at around 200hp. If one where to change their injectors to a higher lb. What kind of HP would be safe to achieve on stock internals?

[cmtapanes]

Can someone tell me the size for the tranny lines? Do we use 5/16 or 3/8. Im planning of getting the combination engine and transmission oil cooler; one like this one:

http://store.summitracing.com/partdetail.asp?autofilter=1&part=SUM%2DG4978&N=700+4294924500+4294839034+115&autoview=sku

[iceman]

http://www.grandamgt.com/forum/showthread.php?t=1263&highlight=trans+cooler+install

[Sprucegagt]

Another HP related question, i read that injector fatigue starts at around 200hp. If one where to change their injectors to a higher lb. What kind of HP would be safe to achieve on stock internals?

No one has found that limit yet. But to give you a reference, I believe 11 PSI is the max amount of boost you want to run on stock internals. But you can only do that with custom PCM tuning.

[timka86]

So does your trani cooler really work?

well i did have it rebuilt, but before it would get really really lazy with the shifts once it got hot, especially in traffic. It shifts great now. I don't have a trans temp gauge so i can't monitor that. But i do feel a difference in driving. plus i know that it elongates trans life.

[BubbaTheHut]

so some ware around 250-275 whp would be a safe limit? has anyone ever blowin up there 3400 because of too much HP?

[3400MAN]

Sorry no. If you make 250-275 whp with a 4T45E and it still shifts for more than a week I'd be shocked. I was nowhere near those numbers when mine began to come apart. My mods were: P&P UIM - LIM, 62mm TB, APOC CAI, S&S Headers, Magnaflow cat, Pro-M MAF, SLP Cat-Back, etc. I HAD to use a ATI just to keep it shifting without replacing the entire tranny. Of course now things are different and you have the option of using better clutches, etc.

[AaronGTR]

so some ware around 250-275 whp would be a safe limit? has anyone ever blowin up there 3400 because of too much HP?


For a stock trans? NO. It will start wear prematurely around the 220-230whp mark. Safe would be to keep it to 200whp and NA to keep the torque down. Boost will up the torque tremendously and thats what kills the clutches. Those of use with built 4T45E's haven't had any problem yet with increased power levels.

No one has blown up a 3400 yet from too much HP. They have blown them up from running too lean though. 275whp would be about the limit I'd advise to try on a stock motor. It might be just fine for a while, but at that power level the slightest little ping and you're likely to break a piston. Pistons are the first weak point. I'm shooting for 300whp next year on a stock engine, but I'm tuning it myself and I don't care if it breaks because if it does I want to rebuild it with new internals.

[jaketuff]

It won't blow up with usual mods... The tranny just wears out from the power added and sloppy play in the stock programming/ internals. There is not much of a way to cure the slippage aside from a totally rebuilt unit with much higher capacity internals - speak to Schweppe, he has perhaps the most abused trns and it is doing well.

I went thru my first 4t45, with 250HP (dynoed) in about 1.5 yrs abusing it with 70k miles. I am still on the second one, all stock w/100% Trickshift, and I beat the snot out of it for 20k w/the SC. I have about 50k on it total now. I got it from a JUNKYARD w/5k, and got it installed for a total out of pocket of $1,200 (the trans was $500). I always have run a cooler. The cooler is okay on the highway and such, but my trans would still bake no matter what to about 240* regularly. So the cooler is a mild band aid... nothing spectacular.

OUT

[MMGT1]

I've beat the piss out of mine. I'm nearing 100 1/4 mile runs. The "hits" in the country, and the 250 to the wheels, still holdin so far. I have flushed and cleaned the trans 3 times now.(150,000km's on it) I don't expect it to last much longer though.........:S