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351m / 400 transmission & TC options

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#1 · (Edited)
351m / 400 transmission & TC options (chose ZF-5 + Dana20)

I have done quite a bit of reading over at FTE but wanted to post up here as well as this forum is a bit busier (more active) so might get more eyes on.

I have about had it with the NP435, love the granny gear but hate just about everything else. Shifts like a bag of hammers, clutch takes the hulk to engage (centerforce clutch?), gearing is spaced out like half of Colorado and while I could probably live without the overdrive I do quite a bit of highway miles, enough that it would make a difference to have it.

I know my options are pretty limited considering I will need a transmission that has the big block bolt pattern while trying to keep the rear driveshaft as long as possible.. this is on an early bronco by the way. I love the granny gear, would like to retain that either through the transmission or transfer case. Overdrive.. half the reason i would like to do this swap.

Keeping a manual transmission what are my options, what about transfer cases?

EDIT: Decided to go with a ZF-5 out of a 460 truck and use the adapter to retain the Dana 20. I will keep this thread updated as my build thread too :)

I'm currently leaning toward a big block zf-5 (some machine work and fab envolved) with either the $$$ adapter mated to a D20 or an $$$$ atlas... I know the np205 mates directly to the zf-5.. but the length!
 
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#49 ·
took some measurements today... measurements are approx but pretty close

Current setup:

Np435 with bell housing (17.5") + Adapter (10") + Dana 20 (10") = 37.5"

Shifter exits floor at 11.5" from front of bell housing

Front Driveshaft = 24"
Rear Driveshaft = 35"

Going to:

BigBlock ZF-5 with integrated bell housing (26.25") + Adapter (1.5") + Dana20 (10") = 37.75"

Shifter exits floor at 13.5" from front of bell housing

Front Driveshaft = 23.75"
Rear Driveshaft = 35.25"

So approximately .25" longer.. even with a margin of error of 1" I SHOULD be good to go as far as the driveshafts are concerned.. probably have to open the shifter hole up.. I MIGHT get away with using the same TC shifter hole but we will see.

Anyway, going to check out the zf make sure its sound and then hopefully reseal it this week and clean it up!
 
#50 ·
took some measurements today... measurements are approx but pretty close
Current setup:
Np435 with bell housing (17.5") + Adapter (10") + Dana 20 (10") = 37.5"
Shifter exits floor at 11.5" from front of bell housing
Front Driveshaft = 24"
Rear Driveshaft = 35"
Going to:
BigBlock ZF-5 with integrated bell housing (26.25") + Adapter (1.5") + Dana20 (10") = 37.75"
Shifter exits floor at 13.5" from front of bell housing
Front Driveshaft = 23.75"
Rear Driveshaft = 35.25"
So approximately .25" longer.. even with a margin of error of 1" I SHOULD be good to go as far as the driveshafts are concerned.. probably have to open the shifter hole up.. I MIGHT get away with using the same TC shifter hole but we will see.
Anyway, going to check out the zf make sure its sound and then hopefully reseal it this week and clean it up!

it looks like you got your driveline measurement backwards

longer front
shorter rear
 
#52 ·
is the ZF/20 longer or shorter then the NP435/20

if the ZF/20 is longer then

longer front shaft
shorter rear shaft

if the NP435/20 is longer then

shorter Front shaft
longer rear shaft


according to your measurements the ZF/20 is longer so again

it looks like you got your driveline measurement backwards

longer front
shorter rear

or you have a rear engine rear steer bronco :clavin
 
#53 ·
is the ZF/20 longer or shorter then the NP435/20

if the ZF/20 is longer then

longer front shaft
shorter rear shaft

if the NP435/20 is longer then

shorter Front shaft
longer rear shaft
zf-5 with Dana 20 is about .25" longer than the current NP435/D20 combo

shouldn't have to lengthen or shorten either drivelines, but right now the front drive shaft is longer than the rear driveshaft, not sure what I got backwards? Maybe i'm misunderstanding the original comment but yes I would have to shorten the rear and lengthen the front if the new combo was longer.
 
#54 · (Edited)
Picked up and test fit the custom spacer.. looks like it should work but wont know until i pull out the current transmission and transfer case...







My shopping list is getting shorter but still a ways off from being complete.

New Centerforce clutch disk for a 460
351W Auto starter
Special Flywheel bolts
New Throwout bearing
Adapter from the ZF-5 to the Dana20
 
#56 ·
So even after deciding to keep the Dana20 and buy the adapter kit for the zf I'm now re-rethinking my decision on TC options.. I would really like to retain a low low granny.. and even gain some gearing options.

One option is the NP203 with the Dana20.. which would allow for a low and high selection in addition to the regular Dana20 gearing - giving me quite the gearing options.. but at a cost, driveshafts, adapter plates.. triple sticking $$$$, not to mention losing about 6" of the rear driveshaft.. which would mean I would probably have to redo the spring perches on the rear end again... more $$$

The other option is just to go to an Atlas.. which comes with pretty much everything i need and will bolt to the zf and only add a couple of inches to my drivetrain... But again.. $$$

I'm in no hurry on this.. and just started to look over the zf-5 and clean it up (need to buy a seal kit) so I will keep weighing the pros and cons and make a decision soon.
 
#57 ·
So even after deciding to keep the Dana20 and buy the adapter kit for the zf I'm now re-rethinking my decision on TC options.. I would really like to retain a low low granny.. and even gain some gearing options.

One option is the NP203 with the Dana20.. which would allow for a low and high selection in addition to the regular Dana20 gearing - giving me quite the gearing options.. but at a cost, driveshafts, adapter plates.. triple sticking $$$$, not to mention losing about 6" of the rear driveshaft.. which would mean I would probably have to redo the spring perches on the rear end again... more $$$

The other option is just to go to an Atlas.. which comes with pretty much everything i need and will bolt to the zf and only add a couple of inches to my drivetrain... But again.. $$$


'm in no hurry on this.. and just started to look over the zf-5 and clean it up (need to buy a seal kit) so I will keep weighing the pros and cons and make a decision soon.
Open up the tranny, and check the oil pump inside. I have heard its failure will trash the whole tranny.
 
#62 ·
Ok I have finally thinned the heard and have a little money to continue on with this project. I have pretty much decided to just use the zf-5 with teh D20 adapter and see how that works out for the time being. I will leave the Atlas swap for another day :)

Just to keep things straight here is my list of stuff to purchase...

12" Dual Centerforce clutch disk for zf-5
Throw out bearing (dodge)
ZF to D20 adapter
Longer crank/flywheel bolts
Dual sticks for a T shift D20
Fabricate a cross member
Brake pedal to make a clutch pedal
351W Auto starter
 
#63 ·
I like where you are going with your build. Keeping it simple.....You have obviously researched every viable option throughout your quest for "the perfect driveline".

I would love to install Atlas as well, however I am worried that time will be it's worst enemy. Parts availability and unforeseen damage always occurs at the most inopportune time. It is not something you can order parts for at any local parts house. That is why I will never put down the coin required to purchase one of these fine units.

You are venturing into new territory - the ability to travel on major highways keeping low rpms at 70mph and could pull anything you wish at low speeds.

I would love to be able to pull my boat out of the water at a snails pace at the boat ramp ( very steep ) and drive to a different state without listening to an engine tool along at over 2500rpm.

Your engine loves low rpms and will enjoy your set up- looking forward to your reviews (pros and cons) when you get this finished.
 
#64 ·
Ok I am about to start the ZF swap, have one or two little items to pick up but the bronco is in the garage and I will start removing the interior tonight and then drop the current NP435 and Dana20 out of it Friday and Saturday.

Only have a few more parts to order.. 351w Auto starter and the clutch plate for the 460 zf-5 however I am not sure what size I need until I pull the current pressure plate and flywheel but assume its the 12" version that is common behind the 400.

I will take as many pictures as I can along the way, I am interested to see what kind of clearances I have between the frame rails, exhaust and how much cutting I will have to do for the shifter.. will be entertaining :-X22
 
#65 ·
Have everything ready to go to pull the trans and TC however after taking a look I think I will just drop the exhaust to get it out of the way.. anyway quit for the night it was getting cold out there.

Old stuff coming out.. nothing exciting...











ahhh so much better...



Picked up some retractable 3 point Hummer seatbelts... going to make this thing a bit more street friendly and remove the two elbow hoops behind the seats and replace it with a removable bar in case I want to put the harnesses back in one day..



anyway hope to have everything out tomorrow!
 
#68 · (Edited)
Well wrestled the np435 and Dana20 out of the bronco this afternoon, ended up taking more floor out as I just could not get that NP435 to slide back far enough. I guess I was going to have to do it anyway for the zf...













Tomorrow I will pull the clutch and flywheel and install the spacer and then do a ZF test fit to make sure this thing will fit!
 
#71 ·
Any intentions of keeping the aftermarket shifter, I am curious if it has given you any trouble? Seems to me that there are a lot more (moving parts). sometimes "less is more". It is cool to look at though
Ya the Dana20 should be fine, I wasn't too worried about it lasting but more interested in crawling gears. I do have the upgraded 32 spline output shaft in it so I should be good.

Not keeping the gearbanger. I wasn't too fond of it, but did its job. It does have allot of slop in the joints and while looking cool added a ton of vagueness to the shifting. Glad to be rid of it :)
 
#73 ·
Is the clutch not the right size- I thought that you could reuse the clutch/pressure plate/throw-out bearing on the 5 speed.. Are the splines or diameter of the input shaft's' different between the two?
I understand the "shimming" of the flywheel is due to the difference between bell housings. You can use a different starter that has a deeper reach within the bell housing, I am not sure but ford made different ones for standard and automatic trannies. Post which starter works with your application.

Looking at the pics is the shifter located that much further to the rear on the 5 speed vs the 4. I hope- that way you can utilize the factory shift arm
 
#75 ·
Slowly but surely....

got the flywheel chamfered today to match the spacer so they sit flush and after work I installed the flywheel and spacer with the special flywheel bolts I picked up...

still pretty clean back here...



metal plate thingy installed :) had to grind a little off by the frame, probably have to do the same to the bellhousing on the zf.. we will see....



spacer on the crank...



and the flywheel torqued and installed



thats about as far as I got tonight, tomorrow I need to unscrew the stud from the exhaust manifold and then probably try to stab the zf in there to see what happens and take the grinder to the bits I need to relieve on the bellhousing.
 
#76 ·
so not too much done today, more running around picking up a few things i needed.

Found a clutch centering tool thought it would be good to have as I was having quite a bit trouble centering the zf, but turns out it was probably not the case.

Pulled everything apart again, measured the run out and was no more than .055 so it looks good.

I wrestled with the zf for a while and realized the throwout bearing center housing was hitting the fingers on the centerforce clutch.

Tomorrow I will take the clutch off once again and grind the fingers down 1/8th of an inch and try again. You can see where the fingers are hitting in the pics.




 
#77 ·
Might be a good idea to cover up those weights (which you probably will, just pointing it out in case you were thinking of being lazy :toothless). Probably not a good idea to get 100K worth of grit in them before they even start life.

Otherwise lookin good..........
 
#78 ·
It's in and the shifter clears everything. Have lots of little stuff to do still on the trans but overall it's in.







I ended up grinding the fingers down about 1/8 of an inch. Slid pretty much right in was just a tight fit and a bit of a pain doing it by myself but not too bad. We will see what happens when it starts I guess or at least turns over but my concern now is the clutch fork as it seems pretty far engaged with the hydro cylinder installed. Guess I will find out what works soon enough. ;)
 
#79 ·
Nice work! I did a similar swap in my 79 Bronco, and it was a fight from the start with the larger input shaft and clutch disc (I also used a ZF5 from behind a 460). I ended up going with a clutch set for a 94 Super Duty from O'Reilly's (you can choose either a 12" or 11", so I went with the 11" for price and clearance reasons). I also chose to go with the mechanical clutch linkage, just because of the simplicity of it, but hopefully your hydro setup works! I have had mine in now for a few thousand miles, and besides some minor adjustments, it has been going down the road fine.
 
#81 · (Edited)
Finally got some me time today and worked on the swap a bit more. Justin was kind enough to lend me his time and press to get the spud shaft and bearing into the adapter housing. Took me a few tries to get the adapter ring lined up but went together really nicely. Then tried to install the twin sticks however the JB fab sticks will not work with this setup, going to drop Jon a line and see what we can work out as I might have to make something custom or go with cable shifters... next up is the cross member. Talked to Justin about it for a while sound like a decent piece of DOM and a Poly bushing might be in my future...

anyway here are some pics.. Dana 20 ready for the spud housing


Adapter ring


Adapter ring installed on the Dana20 and some white lithium grease for good measure.


I know its really hard to see however the big block zf is quite a but shorter than its small block counter part. These two extensions are right in the way of the shifter mount on the housing ring. Both of those extensions have bolts in them that easily come out so not sure what they are for? Might be able to fab something up mounted to them but not sure as its pretty vertical to the shift rails... this is looking up from the bottom of the trans



This is pretty much straight up from the shift forks on the D20



they come out...



I know this is really hard to see but the silver thing is the adapter in between the zf and dana20..


Took some driveline measurements

Rear driveshaft will need to be 30.75" (Originally about 35")
Front driveshaft will need to be 26.25" (Originally about 24")

Who knows how i measured before but its not too far off ;)
 
#82 ·
Took some driveline measurements

Rear driveshaft will need to be 30.75" (Originally about 35")
Front driveshaft will need to be 26.25" (Originally about 24")

Who knows how i measured before but its not too far off ;)
Looks great!! Seems the Dana 20 got 2 inches fatter :haha
 
#83 ·
Bet you a dollar that those bolts- used to hold the bracket for the shift rails on the previous transfer case. I hope that you can grind those down and reuse those for your twin stick. Not sure if yours was twin sticked before, I never have installed them myself but if so a little creativity and you will be in good shape.
 
#85 ·
So just a quick update, I pulled the Dana20 rear yoke and tried to install the Flange but looks like I will need a new seal to go around the Flange as the old one is just slightly too small to do a proper job of sealing... I will have to shop around to see if I can find a new one or order one online.

Measured the rear driveline - 32" so will be ordering my new 1350 driveshaft tomorrow from FrontRange..

I might try to clock the Dana 20 up a couple of holes on the spacer so the front yoke is higher and it should make it slightly easier to build a crossmember.. I might need some extra eyes on the problem if I can thaw out.. brrrrrrr

I still haven't cut the mounts off the zf.. i will be doing that tomorrow

And I guess the last thing to report is I will be headed over to steel yard tomorrow or friday to pick up some plate and something to build the crossbar with, thinking of using DOM but not sure I can get any that is already cut - guess i will find out!
 
#86 · (Edited)
Making some progress...

I have the transmission and transfer case pretty much in the location where it will sit from now on. Friday I picked up a 5 foot section of 1/4 inch plate and 8 feet of 1 1/2" x 120 wall DOM for the cross member - Just waiting on the Ruff Stuff pivot kit to finally fab up the crossmember.

Finally cut off the ZF-5 transfer case pivot points and got the twin sticks installed. I had to cut more of the floor out to fit the sticks, but thats fine I expected it.
4 low just clears the zf-5 2nd gear and just clears the dash in 3rd and 5th.. its close but wont hit :)



I also swapped the rear Dana 20 yoke with a flange for the 1350 driveshaft, will get to the 9 inch yoke this week sometime...



Right now I'm wrestling with the brake/clutch pedal assembly. I had to essentially pull the whole thing out and will be working on that this week to get the hydro clutch setup installed.. hopefully be done with that in a few days. Hoping to finally stop disassembly and start putting stuff back on soon :)

Anyway, crossing my fingers that this swap works will be great to drive it without the vibration or the bag of hammers!
 
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