I have a queston about the Final drive ratios for the 4T45-E Transmission. I have a 98 sunfire with the 2.2L and I want to swap in a 3.4 from a 99-00 grand Am, I also want to replace the tranny with the 4T45-E but I am not really sure which final drive ratios to pick. I will be driving the car about 350 miles one way, every month for a long trip back and forth. The rest of the time just city driving. I'm really not looking for the economy but would like it, if I dont have to sacrafice too much. I am leaning toward the 3:05 to 1 but looking for some input before I purchase one. Anyone thoughts on the 3.63 vs 3.05 vs 3.29 vs 3.91? Thank's for the input.

Simple: for better acceleration, pick the higher number. If you want to get better economy, pick the lowest. Personally, I'd go for the 3.91, because if you're putting a V6 in, it's all about the fun, not the savings. However, since the V6 has a lot more torque, it will still have plenty of kick with the 3.05 or 3.29.

That's exactly why when you look at MPG ratings, the bigger engine options on a given vehicle don't get that much different mileage than the smaller one, because they put steeper ratios in the smaller engines to make up for the lack of power. The bigger engines can handle the higher gears because of their power, so they get good highway mileage by having those higher gears.

I won't go into the calculations, because I'm heading out right now, but another thing to consider is where you want your power band (what speeds). If you're looking for maximum power during passing on the highway, you want your 3rd gear to hit your engine's power band around the 60-70MPH mark. You have to calculate the gear ratio, through the FDR, and then through your tire circumference, to get these numbers. You also have to know the torque curve of your engine. Then you can see what RPM your engine should be at to achieve maximum power where you want it.

I wasnt aware that there were so many options. All that I found were 3:05 and 3:29. The 3:05 is what comes in the grand am se and the 3:29 comes in the gt. I am running the 3:29 with no performance complaints, mileage appears to be slightly better than a stock cavy, maybe 4mpg more. I did think of swapping the 3:05 in for better mileage yet, but didnt want to sacrifice the power in Overdrive since its hilly around here. I hate cars that are continuously are shifting on the highway.


01 cav w/01 3400 gam gt 4t45e

when you get into the 65e i think theres more option don't think the 45e has that many

make sure your not looking at 3400s in the vans or w cars cause there 65e not 45e



JBO since July 30, 2001

NOTa2_4 wrote:when you get into the 65e i think theres more option don't think the 45e has that many

make sure your not looking at 3400s in the vans or w cars cause there 65e not 45e

Good point. Also to add to that, If Im not mistaken the 4t45 is what comes in the grand am, alero, malibuand I think G6. when you start getting up into the bigger cars like the grand prix, bonneville and Impala those are 4t65's.


01 cav w/01 3400 gam gt 4t45e

I went to the bone yard today and looked for the 3.4 engine, I found one from a 97 Chevrolet Venture. The car did not reveal the reason it was in the junk yard and I was a little hesitant to purchase it. I understand that the timing chain cover will need to be replaced on the van 3.4 and possible the oil pan? Is there any thing else that needs to be changed? I also took a look at the 4T45-E transmission from a 99 Olds Alero. It looks like the half shafts are different, they seem larger diameter than the 4t40-4 transmission. Is it correct to say that if I go with the 4t45 from the olds I need to take the halfshafts struts brakes and wheel bearings? And will the computer from the van work with this setup? Do I need to get it reprogrammed? Sorry for all the questions but thank you for your help. So far I have removed the engine and tranny. I need to clean the garage out and get ready for the next step. I have found a good transmission from the alero with a 3.05 to 1 gear ratio. I foundmost of the information about the gear ratio's on wikipedia, just type in 4t45 and it will list the applications. The olnly one with the 3.91 final ratio is the G6 and they are still hard to find in the JY's around here. I tried to post my first picture so I am not sure how that is going to turn out.

Check for milky (chocolate milk) oil or lower intake leaking where the intake meets the heads. thats what happens to these engine.

I assure you that the 4t40 and 4t45 take the same axles. Mine had a 4t40 before the swap, now has the 4t45. The older ones have a larger CV joint which makes them look larger. That might be what your seeing. You dont need to swap any axles or suspension. Thats for the 4t65e stuff from , for example the venture transmission. Make sure that you get the 4 inch stub shaft from the passenger side axle of the donor, this tends to stick in the axle, not the tranny where it belongs. If the axle on that side had a male spline end on it when you pulled it, the stub shaft is stuck on the axle.

As far as the harness goes, you might be on the path for some troubles. Since we recommend getting the harness from the engine donor and I dont believe the venture harness is going to work for you without some extensive wiring and or research into the transmission plug. This is because the venture has the 4t65e in it and your going to be running a 4t45, Im thinking there is a harness plug difference there. I would almost recommend that you go with the alero harness if you can , then work out the minute differences on the engine later. At the most the difference would be in the injector harness and cam position sensor if you use the alero harness on the venture engine.

As far as the ecm goes, the venture one will need to be reprogrammed to accomodate the 4t45 instead of the 4t65. Here again I would suggest to just get the alero ecm and be done in that area.

i believe there are a number of places that we recommend the harness and ecm be all taken from the same car, and on auto's it is even more important to do that. The guys that are using the venture ecm and harness are running sticks, with HP tuners to delete the auto trans stuff , from what I believe.

Picture posting, well I did what I think you did when I first came here. You cant copy paste or use the insert picture thingy. What I was told and what Im still doing is , I opened up an account on www.photobucket.com and uploaded my pics, when you want to insert a pic in your post copy the IMG file below the picture, then paste it in the body of your post. Click the preview buttom to be sure that you did it correctly.


01 cav w/01 3400 gam gt 4t45e

Thank you for all the information. I went to the JY the other day and I did not find any thing of interest. There were 4 vans and one Alero with no tell tale signs of the reason they were in the JY. I think I am going to purchase a engine that has been tested already. I am looking at a 04 grand am with 100,000 on it. I want to pick up the matching transmission a 4T45-e and the computer that goes with the car. Should I get the same year 04 computer as the engine, or maybe a 99 computer which would be closer to the year of my car? The only thing that concerns me is In a previous thread under the (swap sticky) . It does not list the newer cars as good doner vehicles. The Engine is a "E" 8th digit in the vin so I am hopping this one will be better that the van. I think I will have my hands full with the wiring and I dont need to be dealing with mechanical issue too. Anyone have any comments about using the 04 Grand AM engine? I am pretty sure it will work but I am not 100 percent sure. So far I have removed the Engine transmission (125C) and A/C system. Starting to prep and clean the engine bay for the swap. Anyone needing parts cheap let me know. When I was at the JY East bethel MN " U pull R parts" they had a 2000 sunfire with a good motor 2.2L and tranny if any one is interested. Car was hit lightly and broke the steering knucle. I will try to post some pictures on my next message, I opened up a photo bucket account thanks to Jo Mx.

Get the 04 computer. You can not use a 99 on an 04 unless you change out the injectors, or reflash the computer. They changed to the low impedance in 02, IIRC, but I know for a fact that the 04's have them and the 99's don't. Any GA is a good donor vehicle. If you can, get the complete downpipe from the car. Also get the heater hoses and radiator hoses. As far as the engine being more compatible from the GA than the van, it doesn't really make a difference. The ECM/harness will, but the engines are just about identical. I would go for the lowest mileage one over getting the best vehicle. If you have to buy a few other parts because you get the less than ideal donor vehicle, but it's for a considerably lower mileage engine, it's worth it.

Well I'm getting close to purchasing the 2004 3400 with about 86000 miles and it has been tested good. Then I want the 04 computer and the 4t45-e for this engine. My car is a 98 sunfire. Try to get the radiator hoses and the exhaust down pipe. Do I have it right? I dont know why but the 99 engine is 900 and the 2005 engines are only 300-400 it just does not add up. I have read alot of threads about changing sensors and not piggy backing ecm on the 2000 + engines. I do not want to change all the wiring under the dash. I also want the fuel gauge too work. I have a couple more questions do i have to change the sensors from the 2.2 to the 3.4 and how will I get the fuel gauge to work? I hope I have everything right. I plan to purchase the engine this week end let me know If I need anything else right away. Still working on the pictures I hope they will be here soon. Thank again for everyone's help.

Watch out for newer fly-by-wire throttle set ups, 05 - 06 ish (not sure of beginning year) and up. I think they can be bypassed with an older throttle body/intake though. I dont believe any one has been able to use the fly by wire setup on a swap as of yet.


01 cav w/01 3400 gam gt 4t45e

Well here is the start of the 3.4 swap what do you think?





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I went to he JY and picked up the 04 engine with 53K , a 04 tranny with 45K and the ECM 04 all from a 04 Grand Am. The problem is they just cut the wires and they did not have a harness for the engine. The person said when the price of copper was high they sold all their wiring for scrap metal. There is a P and P yard by my place, will a harness from a 99 van do me any good? I have about two weeks to find one. I am planning to have the engine in and mounted by them. Any advice? Thank you for the help.

I am not sure the 99 harness will work. I could be wrong, as I've never compared them directly. AFAIK, all the sensors will be the same, but I'm not sure if the injector harness plug is any different. If you go 02+, you'll be safe.

wat all do i need to swap my 3.4 into my 97 cavy

Kadeem Baxter wrote:wat all do i need to swap my 3.4 into my 97 cavy

All you need is to read the sticky at the top of this forum labled: V6 swap info for 3rd gens.

http://www.j-body.org/forums/read.php?f=30&i=40670&t=40670


- Your not-so-local, untrained, uncertified, backyard mechanic. But my @!#$ runs

lazy idiots this post has been dead since 09 and you brought it back to ask that question go back to the newb section and buy euro tails and a folgers coffee can muffler



JBO since July 30, 2001