I'm looking for some ideas on a tranny swap. I have a 97 PSD with an automatic transmission (E4OD?). It seems to work OK, but I was reading about all these tranny troubles. I have driven manuals for the last ten years, and that's what I prefer, but I heard ATs are better for towing. What's the best of each type? I'm most interested in the newer transmissions (with more gears, etc)

 

i would go with either "Brians Truck Shop" or a "Suncoast"

 

keep youre e40d and ad an over/underdrive. make it an 8 speed, go to gear vendors.com. you can split gears.

 

What he said.

 

I checked out the under/overdrive website, sounds like an awesome set up, I love my PSD w/ 6 speed manual, a good 2 speed auxiliary tranny would make the 6 speed gearbox even better... but I don't see any info on a unit to run between my 6 speed tranny & transfercase. Does anyone have first hand info on an overdrive auxiliary tranny to work with my 6 speed?

 

Some interesting responses so far. I looked at the gear vendors, saw the $2400 price tag, and had to wonder: do I need to beef up the AT? What is the approximate cost of beefing up the trans? Has anybody swapped in a 6 speed? I figure it'll bolt up to the engine, but beyond that, I don't know. I have a 4.10 LS rear gear right now, and my ultimate goal is to cruise at 70-75 mph at about 2000 rpm. If I have to do that with an AT, then so be it. I've already looked at some of the other threads regarding gas mileage and such, but I would like to know what the guys with MTs are doing. Thanks for the input.

 

Are you sure its a 4.10 gear ratio? I thought they only put 3.73s in the 97 and up trucks.

I have a 96 with 3.55 gears and an E40D tranny. I do run down the road at 70+ MPH turning 2000 RPM in overdrive. The ability to do that will be determined by your final drive ratio (that is rear end times tranny output ratio) and your tire size. In the E40D the gear ratio in 3rd gear is 1 and in OD is .7 so my final drive ratio is .7 X 3.55 = 2.49. I dont know what the addon under/over drive units ratio is but all you have to do is to multiply the standard final drive ratio by the addon units ratio to see what it will deliver at the rear wheels if it is anywhere close to 2.50 you should achieve your goal with standard sized tires. If you are running larger tires that has to be taken in to consideration.