I have a C6 with out overdrive and i was wondering if there is a way i could add on over drive to my tranny? I heard it would help my mileage?

 

There are a couple ways. First and probably most obvious is to swap in a OD transmission. The E40d is the trans i believe, it also has a lockup converter which will also help to improve mileage. Or there is the standard trans, the ZF5. Another alternative is an auxillary overdrive unit. This piece bolts to the back of the transmission much like a transfer case, i dont think they work in 4x4 applications but im not sure. Gearvendors is a popular option for the overdrive unit, expect to pay about $2800 for a new unit or about $500-800 for a used that ive seen.

 

It will help mileage, but you can't add an overdrive gear into you C6. You can add an external overdrive unit, like a Gearvendors unit, but that can get pricey... A ZF5 5-speed OD manual trans swap is popular as well. Going to an E4OD automatic is also possible, but there'd be a lot of electrical issues to deal with, like the VSS and the computer...

 

You beat me to it by a minute, Hairy...

 

Ok that answers my main question. I was thinking about buying a manual and putting it in to replace my c6. The ZF5 is a manual right? Can you get O/D on a manual tranny?

 

Yes, the ZF5 is a manual, and 5th. gear is overdrive.

 

Yep and yep, lol sorry phy. The ZF5 came behind them from the factory and have i want to say a 24% OD 5th gear. Another option is a later ZF6 from a 99-03 SD 7.3 psd, but this will require some modifacation and can get tricky. This on is a 6 speed manual.

Regarding the E40D, there is some wiring, sensors, and vacuum lines, but i dont think there are that many of them so shouldnt be too hard, i could be wrong on this.

For the manual swap, you will need the flywheel, clutch, master/slave cylinder, pedal, and likely tranny mount and x-member to make it a bolt in operation. Also, your driveline will have to have the tranny end changed and also shortened.

 

Sorry i didnt see your post before i put mine. lol. How much would a z5f run? Would it be cheaper to buy one that needs rebuilt and rebuild it myself? and this is whats been bugging me about converting it... how would i run a clutch? I was thinking i could make a mount for the petal then take a master out of a donor or could i just use my brake system for my clutch???

 

the zf5 is one of the more complicated manuals im told, and should be left to a tranny shop, something to do with the constant turning pto countershaft makes it a nightmare. Theyre pretty costly to rebuild, but i think you can get em in the 400-600 range. Clutch and flywheel will probably run another 600 assuming you get the single mass flywheel, which is strongly recommended.

 

You can do all sorts of things, just depends on how deep your wallet is and how big your cwanium is. For the Diesel, your tranny choices are pretty narrow. The E4OD is a great tranny, but it is not a bolt-in, either. there will be some mods you will need to do. is your truck 4x4? That makes a big difference. There are aftermarket tranny controllers specifically for the E4OD, that will take care of the Electrical issue. or if your really Savvy, you can look in the late 80's trucks in the JY, as they had the seperate tranny computer under the dash...but there will be some wire splicing you will need to do.

If you went the route of the ZF, as Hairyboxnoogle was saying, also not a direct swap-in...pedal assy, clutch master/slave, etc. I am doing this conversion myself in my 79 as well as adding a diesel.

Any of it can be done, but not very easily. if you are pretty handy with a wrench and a welder, you shouldn't have a problem doing either of these swaps. but that is pretty much it for OD's. and of course the GV overdrive is a nice option, but pricey. AND YES, they will work with 4x4. I used to have one in my 77. worked great. (they go behind the Tcase. just can't be used while 4x4 is engaged)

questions I would ask myself: How much do I want to spend? How much time do I want to invest? what do i want to use the truck for? is the cost of the swap going to outweigh the slight fuel saving you will get?

 

The Baumann controller made my switch easy. Expensive unit but well worth it for me because I got the 4r100 for less than 300. Messing arund with the wireing harness from the original truck did not appeal to me but it could be done. I have a gear vendors to go on behind mine, but in my bronco there just isn't enough room. I would have to build a custom t case to make it work or else have an eleven inch drive line. I might sell that GV. Makes me sad to think about it though. Maybe I'll find a way to fit it one of these days.

 

As has been mentioned, you need a 2wd or 4x4 version of the trans you swap in if you go with the manual ZF-5. It depends on what your truck is, I don't recall seeing if your truck is 4x4 or 2wd? Not sure on the E40D if there are separate versions for 4x4 or 2wd, I would assume there is.

The best thing you could do is find a donor truck and use all the parts you can off that. It will save money and hassle to have all the parts you need available.

 

FYI, Some years (all ?) of F450 are 2wd but use a 4x4 transmission with a parking brake bolted to it instead of a transfer case, so keep that in mind when shopping for a used zf5.

 

Well the C6 is dead... I drove it last night and finally gave up I had to drive reverse all the way home. LOL! But my mom told me to talk to my dad bc he offered to buy a little truck for me to drive while i worked on my truck so imma see if i can get him to buy a zf5. Ive been finding working ones for around 250-300 is there anyway i could check to make sure they are good. I dont wanna buy one and end up rebuilding it. I hate tranny work so id take it to a shop. Its not worth doing it wrong. I already have a set up for the petal designed on my 3d engineering program at school that should bolt on if not ill weld it. And i can get the petal for a few bucks at pick a part in indy. Now im confused on what i need for my clutch? Do i take one off a donor? Or can I run it off my brake master? Im good at fab. and design. and im pretty handy with a wrench. Im pretty sure i can keep the cost under $500 if I do it right. All i need is the tranny, clutch set up and, petal??? Now do I have to ext. my drive shaft for a zf5? My truck is 2wd has a c6 w/o o/d. I forget what my rear axle is ill have to look at the diff cover bolt pattern. Im sure one of you will know tho.

 

Im very handy with a wrench and welder ive been useing them all 17 years of my life. lol. Money is tight but I could manage $500 and possibly a bit more. I use it as a daily driver and i dont put any big loads behind it. I have to drive in town a lot for school and it seems like i end up in town more then id like. I get 12 in the city and it sucks. I do a lot of country driving during the weekend with the guys sometimes 200 miles a weekend. I get 22mpg now when going 50-55. I really want better city mileage and if i could keep my highway miles or even raise them that would be awesome. I'm also looking for a little more power and faster acceleration with a possible higher speed with 5 gears in stead of 3... Would i get better mileage in my truck with a manual? I know it made a huge difference on my jeep even after i lifted it?