building a 4t45e

[Rootie524]

i realize there are many of these threads already but sometimes its easier to start a new one and bring up some old but good topics so myself and others can learn.

now with that out of the way. i was debating between a 5spd, 6spd, or just a 4t45e swap into my malibu. right now the most practical thing for me to do is get the 4t45e and new converter with a more optimal stall speed and use that. maybe ill 6spd swap way down the road.

basically..i dont want to change gear ratios too much. i like having about 130mph being where it maxes out..but id also like better acceleration off the line. so thats where the "i dont wnat to change gear ratios too much" comes into play.

im basically just looking to beef up the solenoids and other crap (if possible) so this transmission can take a good deal of HP from a built 3400 engine. the engine will be NA and if i ever turbo this car it will be when/if i 6spd swap. but it will be built block up. 11.5:1 CR, strip cam, ported everything, headers, pipes..all the goodies. so im hoping to get AROUND 250whp NA and have it streetable. it's more than doable i just need the transmission to be able to handle it. i know the 4t45e's are strong but im no pro..so will it take that power no problem.

and my planned max shift point is around 6000-6500 RPM

[86FieroSEv6]

Northstar Caddy's don't seem to tear them up too badly and they are 275-305hp depending on the model and in a much heavier car.

[Rootie524]

aren't those v8s too? i didnt know those caddys had a 4t45e.. i heard the 45e's after 2003 are built even stronger..so i might be fine with a low mile stock one.

[86FieroSEv6]

To my understanding, whether it's a 4t45 or, as in the Caddy's case a 440t4, the guts are mostly the same mechanically. In any case, I've seen 4t45's handle 300 ponies quite handily. Of course, you would use an external heavy duty trans. cooler and I'd recommend adding a remote spin on filter. It's a lot easier to service and helps the internal filters last a whole lot longer.

[TurboGTU]

If you like turning hard on corners and punching it, the 4t45 won't last, or any trans. Cuz the differential is one weak link to the 4t45.


Blue plates and shift updates will help. A billet accumulator will replace the plastic. 99 up 4t45 chain drive .

Save all the hard work and just drop a 3500 in it and do bolt ons.

[pocket-rocket]

i like having about 130mph being where it maxes out..

I hope your tires are rated for that, otherwise your begging to be a statistic.

[Rootie524]

there isnt really hard work involved. i dont really want a 3500. its not much more beneficial to me, requires extra parts, custom work, and me to buy a whole entire engine. im going to be content with the fully built 3400. and people have said after 2003 the 4t45e trannys are pretty strong stock. and the malibu will never be a backroad car so thats not really an issue. do they make stronger diffs anyway though? why not get one if i can.

and yes they are rated at a pretty decent speed (i forget what but i looked it up before)..they were on it when i got it too. pretty tough rubbers. lol

[3400beretta]

To my understanding, whether it's a 4t45 or, as in the Caddy's case a 440t4, the guts are mostly the same mechanically. In any case, I've seen 4t45's handle 300 ponies quite handily. Of course, you would use an external heavy duty trans. cooler and I'd recommend adding a remote spin on filter. It's a lot easier to service and helps the internal filters last a whole lot longer.

440t4 became the 4t60 and then 4t60e, different tranny all together, and capabable of much more power.

[3400beretta]

Northstar Caddy's don't seem to tear them up too badly and they are 275-305hp depending on the model and in a much heavier car.

And that would be the 4t80, again a totally different transmission.

[robertisaar]

And that would be the 4t80, again a totally different transmission.

also known as the beefiest GM auto transaxle ever made...

why would someone mistake the 45 for the 80??? a N* would probably kill a 40 or 45E within 3 hard launches.... a 60 and 65E would fare better, but not for long.

the 4t40 and 4t45 are NOT strong trannies, they are actually the weakest FWD autos GM has ever made IIRC... which is why you'll only ever find them in compact or lower cars with fairly weak motors...

[geldartb]

d people have said after 2003 the 4t45e trannys are pretty strong stock.

where the hell did you hear that. who ever told you that was high.

the 4t45 can barely supprt the stock output power of the engine and once you start modding the engine (by modding i mean something other than ported intakes) the trans becomes a time bomb. once built up with the blue plate clutches and all the other necessary fixes they can stand the power. i havent heard of anyone breaking an upgraded 4t45.

hell im surprised mine has lasted this long. im not exactly gentle with this car. it definately get's rode hard and put away wet. i do have another transmission in the garage to rebuild.

[Rootie524]

so let me get this straight. 4t45e are shit but are better than a 4t40e. BUT when built up, the 4t45e can support a great deal of power. Could it handle 250+ whp and quick shifts w/ adjusted shift pressures?

can someone give me names or links of the parts to build one up? thanks much

[pocket-rocket]

4 means 4 forward gears
T means transverse (FWD), otherwise if it were an L it would be RWD (longitudinal.. funny little word there)
40, 45, 60, 65, 80 all are a code for the hp/tq specs it can handle- the higher the number, the more torque, which I'm sure you've gathered so far
e means electronically controlled.

This concludes your GM FWD transmission training exercise for the day. Thank you, and have a safe trip home!

Edit: BTW, each transmission model has their own quirks and weaknesses as nothing is ever perfect. Did you ever hear the DOHC had 275 hp but they had to tune it down in the ECM because of the transmission?

[robertisaar]

Did you ever hear the DOHC had 275 hp but they had to tune it down in the ECM because of the transmission?

oh god, not that again

true there is some torque limiting in the PCM, but not that damn much...

[pocket-rocket]

oh god, not that again

true there is some torque limiting in the PCM, but not that damn much...

It was a joke that got a much needed laugh on my end. They might have cut the spark down, but there's no way they did it in the ECM or Ben wouldn't be able to keep chips in stock. He had taken a pic way back in the day when he used FreeScan and WinBin for tuning. He had edited the decimal readout on the right in WinBin to read something like 275HP=OFF or something like that and taken a screenshot of it claiming he found it in the code (as a joke).