Cracked TH350 case

[Sandcastle89]

Hello all,

Wanted to make a post - it has been a minute. After removing my TH350 for an overhaul - I noticed there is a crack in the back of the housing. Wanted some input from the community if I should try to repair this or replace it. Found a K stamped housing on evil bay for around $500

The housing has a "K" stamp in it (barely visible in the photo) - which after doing some looking online - seems it means a heavier duty case. What do you guys think?

 

[Strick]

I'd replace the case. Just went thru this with my SIL's 86 TH400.

HS

 

[Edelbrock]

I would drill a hole just past the end of the crack (to stop the crack from continuing), and then I would call around different welding shops. Tell them you are a mechanic, and need to have a 4" crack welded on a trans case. A reasonable welding shop should charge $50. Its a very quick job, so if they try charging over $100, then move onto the next shop. You might even get them to do the welding for free if you offer to change the oil on their truck for free while they do the welding (with you buying the oil and filter).

 

[legopnuematic]

That crack isn’t at the bell housing, it’s at the output shaft that mates to the adapter for the transfer case.

Sure someone could blob some spoolgun MiG on it, to do it right is going to be far beyond a 5 minute job. Unless if you have an ‘in’ with someone who does this sort of repair work, the chance of getting back a scrap housing is (in my opinion), pretty high. Or messed up worse than it was to begin with.

I would expect if you found someone capable of doing it, to be looking at $200+. Have to figure the prep of cleaning the area properly, drilling and Veeing out the crack, cleaning again, the welding, after weld dressing and keeping the sealing surface and threaded hole intact or the work to clean them up. That area has been exposed to transmission fluid on the inside for 50 years, if the crack is through to the outside, it’s been subject to all the crud on the outside of the case.

Labor rates of course vary by area, but a competent welder capable of doing this properly isn’t going to be charging $30/hr for their labor, it’s going to be $100+/hr, probably $150+/hr. Figure 2hrs minimum between clean up, prep, welding, post welding cleanup, machining if required.

Might reach out to some transmission shops/builders in your area and see if any have a good bare K case for purchase or something.

 

[Ricko1966]

This was a lot funnier when edelbrock's post said call welding shops and tell them you are a mechanic and have a crack in a bellhousing you need welded up................
After they get done laughing at you for telling them you have a cracked bellhousing. They are probably going to ask you where you are a mechanic at, to which you should probably tell them Ray Charles auto repair. You can use a 2wd th350 case,since you were doing a rebuild anyway.I would think damn near anywhere in the US you can find a th350 core transmission for 100.00 . Check your local pick n pull see if they'll sell you a core,or find out how much for a good th350 from the yard. Maybe even find a good used TH350 on craigslist. Dammit @legopnuematic types faster than me.

 

[nvrenuf]

With respect to the heavy duty “K” cases, I’ve never noticed much difference in case thickness or extra ribbing, etc. The only real difference I’ve seen is the converter cover flanges being wider, thicker and threaded for the thick converter covers.

Note: my experience is with th400’s