I bought a mitchell overdrive unit used at an automotive related swap meet and sent it out to mitchell almost a year ago and had it completely rebuilt and had the overdrive ratio installed that I wanted. for those of you not familliar with the mitchell , its a divorced all aluminum unit that sits in the place where your drive line center suport bearing used to go. they had many diferent ratios available for it but I went with one that also gives me a dirrect ratio because I have a 4X4. my over drive drops my rpm's exactly 400 in 6th gear which from what I understand is a little more than half of the rpm drop of a gear vendor . now, my truck is probably the worst to drive on the freeway of all the dodge diesels because its a 6 speed and has smaller tires because its a dually. I went from 63mph at 2000 rpm in 6th gear to 75mph at 2000 rpm. now at 65mph Im at right around 1625rpm!! a world of difference for me. this unit is manually shifted and full synchro and I now have a 3rd gear shift lever that says high and low on it. and I can tow in 6th gear over where gear vendor advises against doing so with their unit. towing with it was very important to me. the mitchell overdrive is a monster . it looks like a big square cast aluminum box with cooling fins all over it. its rated at 35000 lbs! and Im told by the manufacturer was actually well under rated for liabillity reasons. I had to make my own cross members and have 2 drive lines made from scratch and saved my factory drive line in tact which I am wrapping up and hose clamping to the frame up under the bed just incase I ever need it. cant wait to get it out on the road and see what it does for mileage. . these over drives are no longer manufactured and it was explained why to me by mitchell. about 85% of the population that buy a new truck buy an automatic, not a stick, in 2000 mitchell stopped producing this unit because of all the computer controls on the new automatic trucks didnt get along with the over drive. since this unit was realy only easily installed on stick trucks and there was such a small amount of stick truck purchased compared to auto trucks they decided to stop producing them in 2000. anyway, Im happy as heck so far and now have 12 forward gears and 2 reverse gears! LOL will post my mileage after I get it figured out.

 

Keep us posted...And maybe some pics too!

Tony

 

yes! i want some pics! what keeps them in business if they arent making anything anymore?

brett

 

Haha, no maybe on pics, pics are a MUST!! Sounds like a cool piece...

 

Pics!!!!!!!!!!! and how much do they run compared to a GV???

 

lets see if this works for pictures http://s190.photobucket.com/albums/z317/tidycat1100/

 

they still make overdrives , just not overdrives for pickups anymore

 

Ok now hows that work,you engage the overdrive and pick up the extra gears?

Kinda like the low side gives you 1-? then the high side gives you ?-12 ?

God that reminds me of some old cabovers I used to drive,crap I'm getting old.

Pav

 

yea that sounds cool. I would like to lower my rpm, but Iam afrid of cooking my tran. when I need to yank that13k load. I have auto 4sd ho w3.7

how would I do with 3.4 anyone have 3.4 on ho 4auto?

 

NO such thing as 3.42 gear set in a Common Rail, 3.73's and 4.10's are your option from the factory. There are 3.42 available aftermarket.

 

Pretty nice man!!!

 

That's awesome! So, how do you shift it? Do you clutch for shifts? Can it be used with exhaust brakes as well? --Eric

 

Awsome! I would love to get my hands on one of those. Please keep us updated.

 

very cool....

 

to shift it you just push in the clutch and shift. sure it can be used with an exhaust brake and yes I can tow with it. the reson a gear vendor will burn up your tranny while towing with it is that the gearvendors overdrive is to high geared for towing, mine only drops rpm's a reasonable 400. not 700 like the vendor unit.