3speed auto to 4speed auto

[JH]

I have a 91 lumina 3.1 with a 3 speed auto trans. I have been told that the 3 speed isn't a very good tranmission. I do have a few 4speed auto trans that came off 3.1's and i am wondering whats involved in swapping them. And how much better the 4speed one is.

[Quinky]

Better is a general term.. what do you wanna know that is better about the 4 speed?? The 4 speed is going to be better on gas, you'll run lower rpms on the hwy.. and that is about all.. The 4 speed auto aka 440T4 or 4T60 is a weaker transmission then the 3 speed... When it comes to performace wise the 4 speed is much heavier then the 3 speed..with a 3 speed there is a lot that can be done to beef it up to go faster.. including 4.10 final drive gear raitio.. My personal preference if you wanna go fast is to stick with the 3 speed..

To swap a 4 speed though into a lumina wont be hard.. I believe axles are differnent.. but the luminas came stock with a 4 speed so with the right mounting brakets it will just bolt right in.. You will need to run a vacume line for the shift mod on the 4 speed though.. a 3 speed doesn't have one

[TurboGTU]

You'll also need to get the memcal from a 4t60 equiped w-body..Lumina or Grand prix. You'll need the code for the OD feature. You'll also need the harness for it too. The 3t40 only had one wire for the TCC..the 4t60 has the TCC and pressure selinoids. Also the shift/nutral safty switch and wires. I could give you a rundown on how to wire it up. I've seen Grand Prix with a 3t40 also. Yea..your right Quinky..they are different axles...so you'll need them too.

[X11_STE]

Or, if you dont want the hassle of changing the computer, look up how to switch a 700r4 from electric shift to fluid shift. The process is EXACTLY the same on a 440t4. Not sure about the 4t60 though.

[Quinky]

You wont need to swap anything with the computer.. the 440T4 and 4T60 don't have anything that is controld by it... FYI, a 440T4 and 4T60 are both the same transmissions.. A tv cable controls shift points and a vacume mod controls shift feel(how hard/soft the transmission shifts).. Lock up is turned on hydrolicly by working a pressure switch in the valve body.. The external wiring harness is different between a 3 speed and a 4 speed.. to make the swap more simple I would wire lock up to a switch in the dash so you could manualy control it.. having lock up come on when you are doing 65km up a small hill luggin the motor is anoying.. :s

Or, if you dont want the hassle of changing the computer, look up how to switch a 700r4 from electric shift to fluid shift. The process is EXACTLY the same on a 440t4. Not sure about the 4t60 though.

A 700R4 isn't electronic controld... its newier cousin the 4L60E is.. the 4L60E being baised off the 700R4 for the most part... The lock up soliniod on a 700R4 only has 2 wires going to it.. one is power the other is a ground.. power is provided constanlty to the soliniod.. when cruising and conditions for luck up to be on are met..Hydrolicly a pressure switch is activated, grounding out the soliniod and turning it on.. This is the same principal used for both the the 3peed and 4 speed..

Some of the newier modle 3 speeds have an extra switch in the valve body.. It is a temp switch.. This is used so that lock up wont be activated untill the transmission reaches operating temp.. This adds in cold starts and getting the transmission up to temp faster...

3speeds have 2 wires or in newer modles 3 wires.. to the lock up soliniod.. I believe it can even have 4 wires to it..I know for sure that through out the years there are 2 different plugins for the lock up soliniod, but I think there is a 3rd I can't remember completely.. It's colour coded... White harnes plug - Blue plug on the transmission, Black harness plug - black on the transmission and I believe white to white as well...

[asylum-motorsports]

Better is a general term.. what do you wanna know that is better about the 4 speed?? The 4 speed is going to be better on gas, you'll run lower rpms on the hwy.. and that is about all.. The 4 speed auto aka 440T4 or 4T60 is a weaker transmission then the 3 speed... When it comes to performace wise the 4 speed is much heavier then the 3 speed..with a 3 speed there is a lot that can be done to beef it up to go faster.. including 4.10 final drive gear raitio.. My personal preference if you wanna go fast is to stick with the 3 speed..

To swap a 4 speed though into a lumina wont be hard.. I believe axles are differnent.. but the luminas came stock with a 4 speed so with the right mounting brakets it will just bolt right in.. You will need to run a vacume line for the shift mod on the 4 speed though.. a 3 speed doesn't have one

4:10 final drive ratio??
HOW?
Thanx Eric

[Quinky]

3.33 final drive ratio and a custom 32/38 transfer gears I believe..

[sharkey]

i figure that to be 3.95

[asylum-motorsports]

I would really like some more information on this 4:10 or whatever FDR.

Are there places that supply these parts.

Thanx

Eric

[TurboGTU]

I think its the chain and sproket from a quad app..and the FDR of a Van or W-body. Mines is a 3.33 FD...han't counted the chain and proket.

[asylum-motorsports]

Ok that is a start. Thank You.

Anyone have any part numbers? Or more specifics.

Thanx

Eric