Well, I did it again, I cracked another NP435 nearly in half:eek:

It happened, at CalROCS Victorville when I was trying to pull Capn America, off the course when he lost both his front axle shafts. I had it in reverse, and was backing uphill with the winch cable attached to his rig, when I heard a loud bang, and all of the fresh gear oil I had just installed 2 days earlier, dumped out in about 15 seconds.
It still ran, and shifted OK,(but made a hell of a racket in reverse) :D
So I continued driving it around slowly with a dry case throughout the weekend.

Im not excactly sure what caused the failure this time.
Recently the tranny had been popping out of reverse, when in low range, under a heavy load. But it worked fine just backing up normaly, and made no strange sounds or vibrations.
When I dismanteled it yesterday morning, the reverse gear was completely trashed with big gouges out of many of the teeth, and 3 or 4 completely busted off.
The crack in the case runs right through the countershaft support at the bearing.
I am wondering if reverse got bound up, and either forced the gear or the shaft to stress the case and snap it.
That 8:1 reverse gear has the ability to generate monsterouse amounts stress behind a 300 hp V8.

To confound the matter, I also ripped a nearly new poly tranny mount right in half (the bottom section of steel that attaches to the cross member, completely snapped off).
So the culprit for the tranny case snapping could have been, that it wasnt being held in place. The drive train may have buckled, and snapped the case.

In any case, I scored another tranny with a very recent rebuild, and got everything back together. I also redesigned the tranny mount, and added a torque arm. My tranny supplier said he would keep another NP435 set aside for me, and then laughed.
I told him I wouldnt need it,.....but still thanked him for keeping one around for me,..I hope I dont need it. :rasta:

Here is a pic of the :nuke:

Do you have a real good t-case mount ? That could be the problem, if the t-case gets some good leverage it could crack like that.
Once the case moves/spreads the gears are gonna get messed up.

yep you need a torque arm. when i was running the np435 in my jeep i started without one. every trip off road i would break the threaded metal piece out of the poly mount. not sure if it caused your tranny to break though.

I have always used a torque arm in the past, but,... I recently moved my entire drive train forward and downward a couple of inches so that I could shead the body lift, I installed when I swapped in the 5.0. In a rush to get ready for CalROCS, I ran out of time to fab an entirely new cross member and mounting system, so I modified and reused some bracketry I had available, and left the torque arm off. I built some very sturdy mounts yesterday, when I bolted #3 in its place.
Ill do some testing today.

might sound stupid but you might wanna check your axle gears to make sure same??!!:confused:

Maybe you should replace it with a T-18. This way you can write an article on the strength differences between the 2. Won't a T-18 bolt up easier to a 5.0 anyway?

I don't recall how you took out your 1st one, but I do know that reverse is usually your weakest gear on the case. The internal torque is applied to the case differently because of the reverse idler shaft. I blew the whole side of a Muncie RuckCrusher out on the street once in reverse. I mean the whole reverse idler shaft and gear!

h8monday,

let me guess what the problem is -

a) does your Atlas t-case has enough flexibility in it's mount?
is it posible that it sits in on a stiff mount or with a side mount which is not flexible enough, and those mounts do not allow it enough circular motion?
this can be one reason, and if it is, there is no tranny in the world that wo'nt break it's housing, sooner or later, because it would then be caught between the circular movement of the motor on it's mounts and the stiff position of the t-case!

b) if this is'nt the reason, make sure you have at least one(although two on both sides would be better) connecting rod from the t-case through the tranny to the housing bolts on the engine.

i used to break my transmission in situations of high load like the one you described.
once i installed two rods which held firmly all the units(motor, trany, t-case)as one, and at the same time allowed them to move with the engine's motion on suitable mounts, i ceased breaking tranny tails and other components.

in such situations of torque loads, the tranny's case, especially if it is made of aluminum, is the first to break.

i think that if you'll make sure those two things are mended, your transmissions dealer would have to sell the one he's keeping for you to somebody else:flipoff2: :flipoff2:

peace & love:beer:

frogman

t h e F r o g (http://www.thefrog.alloffroad.com)

The NP435 is tough fawkin case, I don't think you are breaking them because of HP of 5.0 and big tires. I used to work in a shop were we maintained a fleet of medium and heavy trucks. Lots of the Fords up to 28K GVW used the NP435 coupled with a 2 speed rear. We used them to deliver equipment and would often tow a 25K trailer along with a loaded truck. Thats a CGVW of 53K, which we often were pushing :D. The only broken NP435 I saw in eight years other than lots of syncros ;) was a broken output shaft due to driver droping the clutch with a full load :eek: . I think some reworking of your mounts is in order. Just my two cents

Originally posted by dorfs
Maybe you should replace it with a T-18. This way you can write an article on the strength differences between the 2. Won't a T-18 bolt up easier to a 5.0 anyway?

I don't recall how you took out your 1st one, but I do know that reverse is usually your weakest gear on the case. The internal torque is applied to the case differently because of the reverse idler shaft. I blew the whole side of a Muncie RuckCrusher out on the street once in reverse. I mean the whole reverse idler shaft and gear!

Looking at both trannys in front of me and from what I know,, they mount the same minus different input and output shafts for different applications. Many fords came with both of these trannys. What were you thinking the difference in " T-18 bolt up " is? are there different bolt patterns available on the same tranny?

Originally posted by H8monday
Well, I did it again, I cracked another NP435 nearly in half:eek:

snip

That 8:1 reverse gear has the ability to generate monsterouse amounts stress behind a 300 hp V8.




Reinstall the TQ arm. The case will never handle the stress otherwise.

I run the same tranny behind a strong running 351 (can you say strong and 351 in the same sentence?) and a heavy as hell 78 Bronco. TSL's and lockers, so good hook up. Never broke the 435 case. You got to have some issues with your mounting setup. Try the TQ arm either attached to the tranny or TC, maybe both in your case...LOL

2 cases,,,damn.... if ya gona do it, do it big.... and in your case often..
:flipoff2:

H8Mon,
Wow, you are tough. The 8.26:1 reverse gear does look weaker than the forward drive gears, and surely develops more direct torque which feeds back through the case under extreme load. But break the case? Shee-ice.
I've run into some severe torque woes with my NP435, but never broken the case. I have a 4.4L H.O. MPI, I-6/NP435/D300w/4:1,4.88's, and 36's, putting out 130:1 in low/low. For you the weak link was the trans case. For me the adapter was the weak link and took it in the shorts. I cracked the cast iron one and had to go to AA's aluminum version. I found out the skid plate was bottoming out the end of the t. case under twisting load and putting a reverse torsional stress leverage back thru the adapter and trans. The 1/2" bolts would get wonky in the holes connecting the adapter to the trans. I finally used studs and 271 locktight just to keep it together. I don't use the torque arm.
The final solution involved Bullet Proof engine mounts keeping the engine/trans/t.case from twisting so much and making sure that the eng/trans/t.case combo stayed in ONE PIECE, unobstructed by stationary parts on the Jeep (like frame/skidplate, which I also made stiffer). All three of the triangulated engine mounts, rear mount 'float' about the same amount, which is just enough to absorb the twisting of the frame. For me the problem is now solved. I think your problem was the unintentional leverage feeding back on the case, but you've given me one more thing to worry about.
regards, as always, jefe

H8monday: what have you done to your 5.0? I plan to run a similar setup as you in my toy but not sure if my motor will be as built as yours.

Those aren't rumor's about you are they? Congratulations not just anybody can break one of those :D

Come on Now man, dont ya watch the Red Green Show on Public Access? Duck Tape the handy mans fix it tool. Remember if women dont find ya handsome, they should at least find ya handy. If at first ya dont succede then switch to power tools.

:flipoff2: :flipoff2:

Note: I used to watch TV back in College, now with the shop i dont even have cable. No time to watch anything.

Fleckster

Maybe it's time to take up a new sport. :flipoff2:

Does anybody have a pic of their torque arm setup? I dropped in a NP435 w/ D300 a month ago and just have a crossmember holding the tranny up without any support to the D300. Is this bad?

if you were a real man like roggy you would just put a rachet strap around it and run it. hell that thing is good for at least the next few rock crawls. don't worry about the oil either you will be going slow. :flipoff2:

Yeah, does anyone have pics of their torque arm setup or can shed some light on where and how to mount them correctly?

Originally posted by Lance
Maybe it's time to take up a new sport. :flipoff2:



Hahahaha, Yeah at least I was present, when I busted up my junk,..... by the way how is that train wreck you call a cruizah, doing?:flipoff2:

Originally posted by camo
if you were a real man like roggy you would just put a rachet strap around it and run it. hell that thing is good for at least the next few rock crawls. don't worry about the oil either you will be going slow. :flipoff2:

Thats why Bob is a legend,....but I deserve a little credit. I climbed under Roggy's rig the morning after he busted his stuff, to try and a lend a hand. I jokingly said, "I think you could use a ratchet strap, and be on the trail in a half hour". He showed up at our camp about an hour later and said he was ready.

By the way,
I ran my rig for about a week without any oil in the tranny, it made a lot of noise but, everything but reverse worked just fine.:flipoff2: I think its a viable weight saving tool you could use on that lightweight tube thingy your running.:D

And if you use a dab or three of JB Weld in addition to the rachet strap, you could even refill it.

Originally posted by diiulio
I dropped in a NP435 w/ D300 a month ago and just have a crossmember holding the tranny up without any support to the D300. Is this bad? [/B]

no, it's not bad.

there is no need for two mounts. one mount over the crossmember is enough, especially with a light weight
t-case like the D-300.

all you have to make sure of, is that in full twist of the engine on it's mounts, the t-case does'nt touch any hard metal, like the crossmember or anything else around it.

also make sure that the mount is in good condition and the rubber is still flexible.

the torque arms come stock with the NP-205, and the t-case has two holes on it's side to which the torque arm is connected. it is a round 7/16" or so steel rod. from the t-case the arm goes on towards the tranny's housing and bolts to one of the housing's bolts. you have many lengths of torque arms according to the model of the vehicle. it is holdind the three units(motor, transmission, t-case) together and when the motor twists, they all twist together, and this is why it's very important that none of them touche any hard object on their twist.

this is done mainly because the NP-205 is VERY heavy, and could break the tranny's housing just because of it's weight(combined with stress situations).

if you put your vehicle through very difficult situations and hard wheeling like in events & competitions, you should have a torque arm too, but you will have to have it fabricated.

it should be made of a steel rod which will be very strong yet flexible.

i'll try to get a picture of it and post it.

BTW - if you do get tough and rough in your wheeling, you'd better take care first of all of your D-300 output shaft, which will probably be the first victim of that hard wheeling, especially if you run tires bigger than 36". get a replacement output shaft with 32 spline.

hope i did'nt make you tired with all the bla bla.........:D :rasta: :D

t h e F r o g (http://www.thefrog.alloffroad.com) :beer: