700r4 Strong Enough?

[njdevi11]

Is a 700r4 Strong enough to put up with our diesels?

I'm thinking about switching back to an auto but I think that its only rated for 350lbft of torque and could be a tad light for 6.5 which would put out around 250hp/450lbft when tuned properly, right? with the harsh driving that I plan do with this should I just stick with the 4 speed manual or don't settle for anything less then a turbo 400 and put a manual shift kit in it?

[SCREAMINXL]

What vehicle are you wanting to put it in? If the vehicle is light (like a jeep) then yes it will work if built properly, but it still wouldnt be my first choice. If you are going to the work of installing an automatic/OD then just use the 4L80E. But these conclusions are based on very little info of what you are doing. Shoot back some extra info on your project.:)

[grancito]

the 700R4 was a bad trans as it had some weak areas, but I have 170,000 miles on a rebuilt with the upgrades and the only thing that failed was the first/reverse roller clutch. I pulled it apart and everything else was like new, so put in the roller clutch and fine. You must have the heavy overdrive sprag clutch installed, the original is no good. There are some oil way drillings to do as well.

[njdevi11]

Yes, this is going to go into my jeep, The info on the project is in my signature. I plan on using it pretty hard. Turning 36"-40" tires through mud and on rocks, via an np205 and 4:10 gears in a dana 44 front and dana 60 rear. My main objective for this project is "bullet proof".

The 700r4 seemed attractive to me because of the overdrive, low 3:1 first gear (a th400 is 2.6:1), its inexpensive, and the adaptors to connect it to an np205 are easier to find. Transfer case selection is a big concern. I don't think I would like to use anything besides an np205, It's the big daddy of t-case's short of the atlas II or other purpose built off road transfer cases. Adapting it to a Turbo 400 would cost me (New parts from a dealer) $300 for the adapter, $200 for the input shaft and then I would have to get the case machined to accept the larger 32 spline female input shaft. The 700r4/th350 version uses a 27 spline male input shaft which dosn't require the case to be machined.

I'd like to steer clear of electronically controlled Trans's because of the need for the computer and complication of hooking it all up. I think right now the choices I have are between the th400/np205 and the 700r4/np205. If I went with a th400 I would get the level 3 shift kit that allows it to be controlled manually, You shift it shifts.

[grancito]

Everyone is terrified of auto trans, to repair, I used to rebuild manual trans, but they are simple, then the last time the 700R4 failed I said to myself, someone made this and someone assembled it, so that means I can repair it and so it happened. I have a manual but it is more of a handicap, use it for special tricks to remove something and the rest, use common dog to take apart, put everything in order so you can put it back, most important.A bit of a pain to assemble, use super glue to hold the spacers in place. I did it , used forward/ reverse roller clutch, used first pressure ring ,1 new first clutch disc, filter and oil total rebuild $37

[grancito]

here we go again, make sure you have the diesel governor on the trans and the the diesel valve body plate to keep the oil pressure up to take the torque.

[SCREAMINXL]

I would say the choice is easy now that we have some info. 700R4 all the way. Would go alot deeper on the gear selection for rocks since you want 36+ inch tires. I think 5.13 will work better this will take alot of stress off the trans. Then let the big tires and OD get you down the road. Do everything you can to keep the trans cool and you should be just fine.

Like Grancito said, use the correct governor and also a diesel torque converter. The Diesel torque converter has brazed turbine fins so the diesel engine doesnt vibrate it into pieces and cause premature failure.

Hope this helps.

[grancito]

other thing, keep the shift cable a bit tight, the shifts will be a bit high and hard but saves wear on the clutches, my discovery during the rebuild. I believe that the TH350 is vacuum controlled, otherwise it would be a much better trans than the 700R4.

[njdevi11]

Sounds like it would be best if i found a purpose built diesel 700r4, Probably best to get the whole thing built for around $500 then spend $200 on a gas trans and $250 getting a new converter and blah blah blah....

With my manual trans right now I almost feel like 4:10's are pretty deep, If I re-gear ill probably end up going balls to the walls and get the deepest gears I can find.

If Went with a th350/400, I would get the shift kit so that I dont need the modulator, I'll just shift it manually so it does what I want, Probably would do the same with the 700r4 but who knows. I think this conversion is going to be further down the line, I've just got my new driveshafts made and Dont feel like making new ones for a while.

Time to get on top of that rear seal and get this thing Crushing rocks. Also need to throw the leaf back in the front pack the engine is really weighing down those springs.

[timlmiller]

the 700r4 is junk unless you know how to build it and the cost to build a 700r4 right is about $1,000.00 just for parts thats why they are cheap to buy

[JD_countryboy]

just an idea on the OD tranny. If you want the "bulletproof" 4l80e, you can get a stage three shift kit that is a total manual shift, you move the selector, it shifts. or so the product descrtion says. I just insatlled a stage 2 in my truck. allows for autromatic shift In OD. Not sure exactly how the stage 3 works though, to make it all manual. Didn't ask any questions cause i wanted the auto shift. I found my tranny parts on ebay. Torque converter, total stage 2 HD rebuild, and shift kit, $443. want more info on the place I got from let me know. Transgo is the maker of the shift kit.