Curiousity kills the cat (not a real cat)

[TwinCam]

Could someone explain this:

4.0L Aurora V8 (250 hp and 260lb/ft) w/4T80-E
3.8L Supercharged V6 (240 hp and 280 lb/ft) w/ 4T65-E
(excluding Pontiac Grand Prix GTP)

Why is the 4T65-E not used on the Aurora or vice versa?

[kobalt]

Your Northstar engine is a very close cusin to the Caddy Northstar. So close they both use the same transmission. GM used the 4t65e on the Shortstar in part to keep the v6 version lighter (~80lbs difference) and more affordable. I also read somewhere that the bolt pattern is different.

[Aurora40]

Probably the largest reason is the PCM. It controls the engine and tranny. I suspect it would be expensive development to come up with one for the Premium V8 and 4T65-E. Also, the 4T65-E sucks, so I'm glad our car doesn't have it.

The Northstar didn't use the 4T65-E because for one, it was the 4T60-E back then, and for another, it can't handle 300 lb-ft of torque like the 4T80-E can.

[kobalt]

Aurora40, you mention the 4t65e sucks, can you be more specific? Is it because of 25% power loss to the wheels as opposed to 24% with the 4t80e? Bad experience with your Regal, perhaps?

[JimW]

4T65-E is okay, not the best, not as seemless as the 4T80E but. The 4T60 series has been used on the vast fleet of 90dV6 and 60dV6 GM cars.

4T65-E = V6 powered cars
4T80-E = V8 powered cars

If I am not mistaken the 6 and the 8 represents the number of cylinders.

[Aurora40]

kobalt said:

Aurora40, you mention the 4t65e sucks, can you be more specific? Is it because of 25% power loss to the wheels as opposed to 24% with the 4t80e? Bad experience with your Regal, perhaps?

Many GS's experience tranny failures with the 4T60/5-E. It doesn't seem up to the task of handling the torque of the 3800 SC. Also, on the Bonnie and Regal I've had experience with, the tranny shifts slowly and sloppily, is confused easily, and the car can roll backwards on mild slopes with the shifter in D. To me it just isn't a quality piece. It's not terrible, and the shifts always feel smooth/slushy, it is never jarring, but it just doesn't inspire much from me.

[kobalt]

Can't argue with tranny failure, my car was missing overdrive when I purchased it and required a new transmission. However after driving a 98 Aurora I must say that the 4t65e and 4t80e seems comparable in shift response/feel - both feel excellent. There is no doubt that the 4t80e is heavier-duty of the two but besides that the transmissions do feel similar (at least to me).

What I like about these transmissions the most is the fact that you can get them to shift at pretty much any rpm via proper throttle modulation - something I could not do as well in other automatic cars that I have driven.

[JimW]

I find that to be the same with my 4T80, with proper feathering of the pedal you can fine tune the shift points. I still need my practise at it to perfect it, but it seems to be unique to GM trannies.

[R4D30N]

if you're ever trying to get speed off the line, and take seconds off your QM time, just put the throttle in 1/4 of the way off the line for less then a second, let off and smash the pedal, you'll run middle 15's

[R4D30N]

by the way, i think the aurora engine is very underrated, as is the 4.6, just for the fact that i've driven cars with more horsepower and torque on the paper, but they had nothing on my car, my freind has a trans am, and I don't think I'd beat it in a race, but I think i could give him a run for his money (i've driven his car:P)

[Marc]

R4D30N said:

by the way, i think the aurora engine is very underrated

It is! Read this article; it quotes 1/4 mile performance
for the 2001 4.0 at 15.1 seconds @ 94.4 mph.

autonetdirect.com/hot_car_01olds.aurora.html


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GM!!! BRING BACK OLDS!!!