Hi everyone. I was just wondering if its common for a 47rh to crack the od housing where it bolts to the back of the trans. I just cracked my second one in a year. Both times it has cracked up the pass side. The first time I had to find a whole trans because I wasn't able to find just the od unit. This time it also cracked the tcase. I'm kind of confused because the truck is not driven hard and its basically stock. Thanks for any input on this.

 

I've heard of this multiple times. Vibration is the major suspect here...

 

Don't bither buyin a new housing or tcase take it to a good welding or machine shop and have em tig it back together when I had my auto I had this happen once and had I tigged it back together the reason mine cracked was because I had it in 4 low and was pulling a loader out of the mud put to much to it and that was all she wrote

 

Thanks for the replies guys. I was wondering about having the one welded the first time, but I ended up finding the trans that is now broke cheap with around 30,000 on a stock rebuild. Right now I'm thinking of getting a third gen. I love this 12 valve but everything around its falling apart.

 

I drained the fluid and found alot of metal particles in the bottom of the pan. And I finally took the od unit off the first broken trans. Its alot worse than I thought. Two chunks are broken off and you can see more cracking from the inside of the case.

 

Ok what the hell have y'all heard of a torque wrench its that fancy ratchet that stops ya from ovetightening a bolt or nut well here we have a classic ecample of what not to do the way its broke is because whoever put the damn thing on didn't bother to break out the book and torque the damn thing the housing is cast alum wich means that its very strong but brittle at the same time when whoever had it apart put it back together the gorrilla tightened the damn nuts and walla there she goes

 

I know they were not overtightened. They were removed with a stubby 3/8 ratchet. The one in the truck now was put on by the rebuilder when it was rebuilt. I'm going to start pulling it apart tonight.

 

You're not gettin the point if the rebuilder over tightened them the yes it will crack and once it has crack or broken the rest will naturally loosen because the pressure has been relieved its kinda like a wheel think of the bolts as the same if 1 lug nut loosens the rest will work loose not so much because they have to pick up the rest of the load but because physics takes over and the pressure changes and with cast metals no mater if its alum steel brass copper or any other alloy they are all brittle and even 3 ft lbs can cause serious damage

 

Where did yours crack at? I understand what your saying about the overtightening being possible. I deal with stuff broke everyday at work from people thinking they need to tighten everything as tight as they can. Just kinda find it hard to believe both 47rhs I have had broke the same way being from bolts overtightened. The trans that was in the truck when I got it supposedly had never been touched. And I know my tcase was cracked before the od unit this last time, I just thought it was coming from between the case halves. I'm leaning more towards vibration stated earlier. The truck has a bad vibration at just over 70mph, so I just never drive over 65. I'm just wondering if the vibration is still there but just not noticeable.

 

Check your ujoint at the tcase. Mine cracked on the mounting flange as far as th tcase bein broken that's from a drivline vibe either a ujoint or possibly an out of balance driveshaft. Also check the rubber on the trans mount they tear quite easily