Now that I have had the truck in my possession for a good 3 weeks now, I've gotten the chance to do different tests on it.

Here's my first one. I noticed the trucks RPMs are considerably different than with the old transmission. At 65mph, my truck is at 1800 rpms. At 80mph, it's at 2100 rpms. Why is it so much lower than before? I think with the old transmission, the truck was at 2400 rpms at 65 mph..

Now, here's my question about overdrive. WHEN DO I USE IT? I do a lot of driving around town, speeds zones vary from 35mph to 50mph. I feel like I'm abusing the truck if I take overdrive off though. The rpms start to get high, and you can just hear the truck wanting to shift, and it's at about 2400 rpms. Is there a maximum top speed your supposed to be in without overdrive on? I found that after 50mph, the rpms start to get high, and it sounds unatural.

Here's the other thing though, the truck loses power when I have overdrive on. When it gets in the overdrive gear, this is where my truck lacks a lot of power. It doesn't have the power and throttle response as it does in the first three gears. I found when I take overdrive off, the truck never loses power and it's very quick on it's feet, but then again, I feel guilty driving around with it when the RPMs are much higher than usual. So is it bad to use overdrive at speeds above 50mph? It's just weird how much power I loose when I have overdrive on, that 4th gear just feels like a coasting gear. The first three gears are very powerful though.

 

Your torque converter lock-up probably wasn't working. That why the RPM were higher.

No problem leaving the OD off in the city. If you only want to use it at highway speeds that's just fine.

 

So it's ok to drive with overdrive off even I'm hitting speeds up to 60mph? It just seems like the truck has a lot more power when it doesn't shift into the overdrive gear.

But in regards to the RPMS, it's something that it still does. I mean it seems healthy going down the highway, I just wasn't sure if that was normal. 35" tires, and only 1800 rpms at 65mph? It just shocked me considering it was 600 rpms lower than the other transmission. Why do you think my truck lacks so much power in the overdrive gear? This transmission is heavy duty, would that make sense that it's locking up in overdrive? The stock transmission never had power issues no matter what gear I was in. I'm still just trying to get used to it. The transmission is very strong at full throttle, and I like that, but casual driving is defiantly a lot different.

 

You can leave the OD off all the time if you want to. Most will turn it off while towing because of the loss of power.
OD and converter lock up are for economy not power.
With 33's and 3:55 gears my RPM are very close to yours. Switch to a smaller tire or a lower gear ratio and you should get better OD power, but like I said it is designedfor economy.

Sounds like your old trans wasn't operating correctly but that's what you were used to, the new one sounds correct to me.

 

I agree. What your describing sounds normal to me. I think you old transmissionw asn't working properly at all.

 

lol well whatever the hell the other transmission was...I liked it better for overall purposes, I never had to mess around with overdrive, it's strange. This transmission is much more powerful, it has excellent towing and racing capabilities, but daily driving is a little more of a chore. I still have yet to see what gearing I have. If I don't have 4.56, it's something I'd like to upgrade to in the future to get even more torque. Thanks guys.

 

You could hook up an external switch tokeep the converter from locking up if you wanted to. That would give you more RPM and torque multiplication from the converter but the down side is increased transheat and loss of economy.
If you drive it nicely what speed does it shift into Overdrive? Maybe your throttle cable still isn't quite right.

 

Don't we have that already lol. OD switch?

2nd, The throttle cable doesn't determine when it goes into overdrive. OD is controlled by the computer at certain speed. Mine used to be 45, until I had my computer reflashed after some hypertech issues long ago. It now shifts at 51 and puts my rpm's at a hair under 1500rpm's. This is better for my 3.55's, but I still can't hold a decent hill unless im going 60 + Once I drop below... its a constant up and downshift temper-tantrum until reach the top. The new TPS helped a while back... but still where I would like it.

 

It's going into overdrive around 40-45 mph. I mean I know most guys would think I'm crazy if they drove the truck, but it's just new to me. With the other transmission, I never even had to take it in and out of overdrive. When guys talked about overdrive, I just kind of dismissed it because I didn't know what they meant. No matter what speed I was going, the truck always felt like it had power, therefore, I never thought about it. This transmission, it's very strong in first, second, and third. Then once it shifts out of third, it just loses throttle response. The speed still moves, but the engine just doesn't work as hard as it does in the other gears, it just kind of floats. IF I mash it, it will go full speed, but just casual acceleration it will just kind of float. I can't complain about the other gears thoough, this transmission feels like it has high towing capablities, and I like that. The other transmission would bounce around with any kind of big load on it.

 

I guess what I'm asking is if there is a way to adjust the tv cable to make me have more power in overdrive? Or is that strictly computer related? Also, if the tires aren't calibrated correctly, would this cause the problem? I know they only got it to 33" tires because they didn't know how to calibrate 35s..figures. Personally, I don't like driving around with overdrive off. The truck gets too loud, my gas mileage gets poor, and the rpms reach too high for my likings. But when I leave overdrive on, it pisses me off. It always like skips into overdrive (4th gear) as well. It's never a smooth shift? Is there a reason for that? As soon as it goes into overdrive, I loose power, and the engine just kind of flutters. The pedal has such lack of throttle response that I have my foot down deep just to maintain speeds above 50mph. So everytime I hit a bump in the road the engine throttles up because my foot will hit the gas pedal because of the bump, it's very annoying. Again, 1-3 gears are great and have great throttle response and power, then it hits 4th gear, and then the engine just kind of makes this fluttering sound and starts to kind of bounce around like the old transmission. I like overdrive too because I like being able to get into 4th gear. When I take overdrive off the truck just gets so unbarably loud and unatural sounding at speeds above 50. Any of you guys experience this what I'm tlaking about?