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to overdrive or not to overdrive

  
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to overdrive or not to overdrive

 
Red2N Red2N
New User | Posts: 33 | Joined: 04/12
Posted: 05/23/12
03:13 PM

Question: Does utilizing a transmission with an overdrive gear pass the common sense test when the vehicle will rarely see overdrive? The purpose of the car is street, other than that it may only see less than an hr of interstate driving between trips to the shop to get tunes. I currently have a built 4l60e, that has not gone into the car yet. Thecar will see more street time than anything, so would a TH350 orTH400, either or, get me off of teh line quicker than a 4l60e...with each using the same stall and rear end gearing as a control reference point  

pepsi1 pepsi1
User | Posts: 111 | Joined: 09/11
Posted: 05/23/12
05:13 PM

If I'm under 45MPH I keep the selector in drive 3. I use overdrive after 45. It saves on the trans shifting and trying to hold that gear. I look at O/D as just that, a highway gear..

If your building over 450 FT LBS of torque go with the TH400. Big Cubes the TH400. Hope that helps... A lot has to do with your rear gear ratio...  

Red2N Red2N
New User | Posts: 33 | Joined: 04/12
Posted: 05/23/12
07:21 PM

Thanks Bob, that helped. I'm definitely didn't build a big cube pump neither is it going to see 450FT LBS, since I'm not force inducting or spraying it.  

Scott Parker Scott Parker
Moderator | Posts: 215 | Joined: 12/07
Posted: 05/24/12
08:21 AM

The 4L60E has the steepest first gear, so it will actually pull the hardest off the line. They can hold over 450 ft-lbs with ease when built properly. We've had several daily drivers make that or more with no issues. One of the few down sides to the trans, though, is that unless your PCM has the capabilities to control it you will need an aftermarket controller. Obviously for a car that came with a 4L60E from the factory this is no issue.  

Red2N Red2N
New User | Posts: 33 | Joined: 04/12
Posted: 05/25/12
01:26 PM

I have the PCM to control it, also I did not know the 4l60e had such a steep first gear. 450 ft-lbs was the torque spec that I was given when I asked what its torque spec was. My only concern with this is, how will this impact my 10 sec goal? Will 450 ft-lbs be enough torque to get down the track in 10 secs?  

Scott Parker Scott Parker
Moderator | Posts: 215 | Joined: 12/07
Posted: 05/30/12
10:44 AM

Maybe, maybe not. That is definitely cutting it close. If the budget is tight and you can't afford to send the 4L60E to another builder like RPM, Century, etc than I'd look into a TH350 swap like we did on Dirty Bird.  

pepsi1 pepsi1
User | Posts: 111 | Joined: 09/11
Posted: 05/31/12
08:30 PM

Scott did you read the question? He does that and mpg go out the window!  

Scott Parker Scott Parker
Moderator | Posts: 215 | Joined: 12/07
Posted: 06/03/12
07:53 PM

It doesn't sound like that will be an issue since he won't be using overdrive. The other option would be to convert to a 200-4R. It splits the difference between the 4L60E's 3.06 First and the TH350's 2.52 First with a 2.74:1 ratio, and is plenty durable at that power level when built, has overdrive and is fairly affordable. I believe many Stock Eliminator LT1 guys run that trans.  

pepsi1 pepsi1
User | Posts: 111 | Joined: 09/11
Posted: 06/04/12
02:11 AM

Ok bud I guess maybe I didn't read it clearly?  

Red2N Red2N
New User | Posts: 33 | Joined: 04/12
Posted: 06/05/12
08:57 PM

so i should send the 4l60 to another builder? If I take the TH350 would it need to be bilt as well? Also, I am not familiar with teh 2004R