Why me??? Advice needed, cracked transmission housing. WTF.

[Team Willys]

For what its worth, I Dont hard mount anything. I know a lot of guys do, woodlee has great success with it, but personally I Dont like the vibrations associated with that method. Also, I don't care how stiff your chassis is, they all flex to some extent, especially when being slammed into rocks and such. Like stated above, trans cases Dont flex, they are cast aluminum so they just crack. If it were me, I'd make some motor mounts with tube sleeve poly bushings, put in a real poly trans mount under the trans or under the adapter (you Dont need two mounts right next to each other) and your tmr t-case support already has poly so you are good there. Make sure everything can move a little with no contact to the skid or chassis and then I'd say you'll be good. Built lots of rigs with this combo and so far never had an issue.

 

[patooyee]

Correct, IMO the only way to go.

I've never solid-mounted anything with a stock frame but in general I agree. There are basically only two options:

1. Make sure the motor flexes the same amount as the t-case.
2. Make sure neither flexes (relatively) at all.

1 is nearly impossible to accomplish so that leaves 2.

put in a real poly trans mount under the trans

I would not mount the trans without the t-case being mounted. The t-case will twist and eventually crack the trans since there is nothing holding it from doing so.

For what its worth, my buggy currently is solid-mounted at the block on both sides as well as both heads. My t-case is solid-mounted at both sides. My trans floats between the two, not mounted at all. I am 100% confident my **** ain't going nowhere! Watch, next trip out my trans is going to grenade and kill everyone within 100 yard radius.

 

[hjpcummins]

Re: Re: Why me??? Advice needed, cracked transmission housing. WTF.

Im supporting mine like this, not sur3 if I'm getting myself into the same situation
Iv still gotta run another rear support to the rear of the 205

 

[zukimaster]

I bet Kush is about to have a nervous breakdown!

 

[patooyee]

I bet Kush is about to have a nervous breakdown!

Sounded like it on the phone!

 

[Neal3000]

Pretty weird that he's been riding so much beating the hell outta his rig with no issues for quite a while but then he breaks a d-shaft at speed and now his transmission case is broken do we need Sherlock Holmes to solve this case?

 

[TBItoy]

Pretty weird that he's been riding so much beating the hell outta his rig with no issues for quite a while but then he breaks a d-shaft at speed and now his transmission case is broken do we need Sherlock Holmes to solve this case?

Dun dun DAH!

I think Neal is onto something...



I would definitely address the motor mount and trans mount issues too

 

[patooyee]

Pretty weird that he's been riding so much beating the hell outta his rig with no issues for quite a while but then he breaks a d-shaft at speed and now his transmission case is broken do we need Sherlock Holmes to solve this case?

He's not sure how long its been broken. And there are some pretty obvious red flags recognized by some pretty reputable people with lots of experience. If it were me I would want to address those as best possible to avoid having to rebuild another trans in the future But he is his own man and I'm sure he'll post up what he does with any results in the future.

Just out of curiosity, when you broke your front shaft, was there anything at all left of the shaft still attached to the t-case? Or did the joint break and everything came off?

And to be clear, your advice is to leave all as is, fix the trans and ride?

For what its worth, I absolutely think his driveshaft could have caused it. But I know the way my drive train is mounted, if that happened, my trans would be fine. Unless the driveshaft physically knocked a hole in the case, both my shafts could fly alla round, get stuck on whatever, and the only thing that could break would be more of the driveshafts or the t-case. There's no way possible that the drive train could torque and cause a cracked tail housing like that.

 

[pholmann]

As long as your cage is tied into your frame from front to rear, solid mount everything!!!!!

 

[Neal3000]

I think he should fix it so that engine, trans, and tcase all mount the same, and i don't think it matters too much what method you use, just make it universal. I use those donuts style bushings from AA on mine at the frame on all 3 crossmembers.

The cv at the tcase came apart on mine, it was all still there except the middle of the cv afterwards.

 

[patooyee]

Just for reference, here's my t-case mount from my build thread. I started with poly bushings trying to be fancy. But I ultimately decided to let experience rule out and replaced the bushings with solid aluminum copies. Glad I did.

 

[Neal3000]

He's not sure how long its been broken. And there are some pretty obvious red flags recognized by some pretty reputable people with lots of experience. If it were me I would want to address those as best possible to avoid having to rebuild another trans in the future But he is his own man and I'm sure he'll post up what he does with any results in the future.

Just out of curiosity, when you broke your front shaft, was there anything at all left of the shaft still attached to the t-case? Or did the joint break and everything came off?

And to be clear, your advice is to leave all as is, fix the trans and ride?

For what its worth, I absolutely think his driveshaft could have caused it. But I know the way my drive train is mounted, if that happened, my trans would be fine. Unless the driveshaft physically knocked a hole in the case, both my shafts could fly alla round, get stuck on whatever, and the only thing that could break would be more of the driveshafts or the t-case. There's no way possible that the drive train could torque and cause a cracked tail housing like that.

So if your front shaft broke at the tcase running 50 or so and then beat the hell out of your transmission till you got it stopped you don't think it could crack that pos cast aluminum trans case? You might be suprised, i was. Th400's are weak and thin at the tailshaft area.

 

[Team Willys]

As long as your cage is tied into your frame from front to rear, solid mount everything!!!!!

Highly disagree with this. Seen it done that way time and time again and they all end up with broken tsilhousings or cracked brll housings or broke t-case studs etc. The ONLY time I would do it was in a 100% tube chassis buggy. Then it works most of the time. Can still have issues even then.

When I said to put a poly mount under the trans, I was saying to run it WITH good poly motor mount bushings (like on a control arm or leaf spring) and the poly atlas support ring. So 3 sets of mounts, all poly. I like poly because it seriously limits the amount of allowed movement, but it does allow for some. So when your chassis flexes, and it DOES flex, its not trying to rip the t-case off or bust the bell housing.

 

[pholmann]

Highly disagree with this. Seen it done that way time and time again and they all end up with broken tsilhousings or cracked brll housings or broke t-case studs etc. The ONLY time I would do it was in a 100% tube chassis buggy. Then it works most of the time. Can still have issues even then.

When I said to put a poly mount under the trans, I was saying to run it WITH good poly motor mount bushings (like on a control arm or leaf spring) and the poly atlas support ring. So 3 sets of mounts, all poly. I like poly because it seriously limits the amount of allowed movement, but it does allow for some. So when your chassis flexes, and it DOES flex, its not trying to rip the t-case off or bust the bell housing.

It all depends on how your cage is designed/tied in to the frame. Also how tough your frame is from the start. All of this thread is purely opnion. Nothing is bulletproof!! All you can do is attempt to make your best educated decision on how you feel it should be done. Obviously rubber mounts aren't working for him. He continues to have motor mount problems and now this. Maybe it's time to try something different.

 

[patooyee]

So if your front shaft broke at the tcase running 50 or so and then beat the hell out of your transmission till you got it stopped you don't think it could crack that pos cast aluminum trans case? You might be suprised, i was. Th400's are weak and thin at the tailshaft area.

I think it absolutely would damage the transmission case. But I do not think that it would cause a radial stress crack at the tail housing such as is seen in Kush's pics or that I have had happen on 2 TH350's in the past. I think it would just bash a hole in the case where it contacts. As well it should because, if mounted properly, the trans should be completely isolated from radial stresses as a result of torque.

I don't think your driveshaft slapping the side of your trans cracked the tail housing radially like that if that is the same type of break you are saying you had. I think the torque build up from whatever it was that broke the CV, or the CV binding right before it separated, caused the drive train to twist beyond the point that it normally would. Your mounts eventually bound up causing the transmission to twist and crack. This all happens in a second or less underneath you where you can't see it. Especially with a CV it is possible that the center ball / cage can grenade and the joints can kind of fold on top of each other. When this happens it completely binds the drivetrain but changes the actual length of the shaft minimally. If you are doing 50mph when it happens your driveshaft goes from 50mph to completely locked up in a micro-second. Ford actually has a TSB about this on their Superduties concerning when the NP271/3 cases completely grenade on the highway. In those cases the t-cases aren't mounted at all and the transmission is, so its the aluminum t-case that sees the shock and grenades before the transmission case though.

Here's an example of the Ford issue related to the TSB:

 

[TJTJ]

I know you lengthened the rear shaft. Does it have enough travel now? Maybe bottoming out

 

[Neal3000]

I was running wide open on smooth dirt when it broke and my drivetrain is still mounted the same and it hasn't happened again since. I did eliminate the cv and upgraded to a 1350 single joint driveshaft. There wasn't any binding imo, it was just a tired 30+ year old toyota cv letting go at the worst possible moment.

 

[patooyee]

I was running wide open on smooth dirt when it broke and my drivetrain is still mounted the same and it hasn't happened again since. I did eliminate the cv and upgraded to a 1350 single joint driveshaft. There wasn't any binding imo, it was just a tired 30+ year old toyota cv letting go at the worst possible moment.

Just so I understand you, because I feel like I am missing a piece of the story ... You were running wide open when your front shaft let go at the yoke, leaving nothing left at the yoke and everything still connected to the axle. The driveshaft flopped around slapping everything, including the side of the transmission. This left no damage at the point(s) of impact on the side of the trans case yet caused a radial crack all the way around the tail housing, a point which the driveshaft probably couldn't even reach. (I grant you that it is the weakest point of the case though.) This crack was identical to the one pictured in this thread which JohnG has done 3 times, I have done twice, and countless people on Pirate have done, all fixed by changing mounting methods. Yet in your case there was no unusual torque loads applied when the driveshaft let go as you were going "wide open?" You think the side of the transmission was just super-tough enough to withstand direct impacts by a long heavy spinning steel club and the momentum of the driveshaft moved the transmission sideways enough to make a circular crack all the way around it without putting a hole in the side first?

I guess you were there and I wasn't so only you could know. But I feel like circular cracks that span the entire dia. of the case like you describe are caused by torque, not beating with a club.

Even so, Kush is saying his break was entirely different than yours. His REAR shaft let go at the axle, leaving everything swinging at the t-case. Unless the shaft bent 180* (it didn't) how is it going to double back and slap his transmission? It would first have to get past the t-case and into his undercarriage, which is just hard to believe since angular momentum would be carrying it the opposite direction and not forward. And even if his trans breakage was the result of unusual circumstances only encountered when the rear drive shaft let go, I would think that he would want to address SOMETHING so that he wasn't having to replace his trans every time he busted a rear shaft.

 

[FlatlandFSJ]

I know you lengthened the rear shaft. Does it have enough travel now? Maybe bottoming out

I don't have nearly the experience most of you guys have that are posting in this thread, but I did break a th400 in the same spot cause of this ^^^^^ It was the front slip in my situation, poly mounted everything in a k1500 I swapped a 454/400/205 into a few years back. Apparently the front slip would bottom out by about 1/4" or more before it would hit the bumps. Hit a speed bump(very large pot hole) doing bout 65 and it instantly spilt the case and it kept pulling for about 5 minutes before it locked up. Ive also seen this crack in jack.Bs k5 ultra 4 build. He went through about 4 cases, 2 that where plated and shaved of casting seams. It would heat up the slip so much that it would bind up and try to remove the tcase from the trans on every bump.

Id look at the motor mounts, sounds like that's about the only place in Kushs driveline that really moves around. And im not so sure a bound up slip on the rear shaft would even crack the tail housing since its inline with the mounting face on the trans.

 

[Neal3000]

Just so I understand you, because I feel like I am missing a piece of the story ... You were running wide open when your front shaft let go at the yoke, leaving nothing left at the yoke and everything still connected to the axle. The driveshaft flopped around slapping everything, including the side of the transmission. This left no damage at the point(s) of impact on the side of the trans case yet caused a radial crack all the way around the tail housing, a point which the driveshaft probably couldn't even reach. (I grant you that it is the weakest point of the case though.) This crack was identical to the one pictured in this thread which JohnG has done 3 times, I have done twice, and countless people on Pirate have done, all fixed by changing mounting methods. Yet in your case there was no unusual torque loads applied when the driveshaft let go as you were going "wide open?" You think the side of the transmission was just super-tough enough to withstand direct impacts by a long heavy spinning steel club and the momentum of the driveshaft moved the transmission sideways enough to make a circular crack all the way around it without putting a hole in the side first?

I guess you were there and I wasn't so only you could know. But I feel like circular cracks that span the entire dia. of the case like you describe are caused by torque, not beating with a club.

I have an Atlas, they don't have a nosecone so the cv or yoke is right beside the tailshaft of the trans. It also broke off the rear corner of the trans pan mounting surface, which was right in line with the crack. In fact i bet it hit that corner first which may have torqued the whole case. I don't know why it didn't punch a big hole in the case but it didn't. And i think the fact that it never happened before and hasn't happened since is pretty good proof that the shaft did in fact crack the case. Maybe if you had been smart enough to go to GT instead of ugay you could understand this

As far as Kush's **** goes i totally agree that he needs to fix his mounts, that **** under his trans adapter looks like something a pot-smoking crackhead would fab up. And how did he find the crack, did it just start leaking fluid?