I have a mildly built TH350 transmission built by Monster transmission in Florida. The case cracked half way around the top about 4" in front of where the tail housing bolts on. I also have another stock, worn out 350. What does it take to swap out the internals? Are there any special tools needed? Any tricks? Any info appreciated! Thanks!!
a picture would help. if its not that bad just leave it. i had one with a crack, and i was like fuck it! i still have no problem with it!
Its bad enough to where it's pumping a lot of fluid out so I can't just leave it. You can't see the crack in the pic so I drew it in (black line). It's cracked almost all the way around.
On a tranny if you don't know don't do it. It will cost you more if you show up at a shop with a bucket of parts and a case than if you just took it and had it done . Just my 2 cents.
oh shit! yea mine was in the bell housing! way different, take it to a tranny shop. of buy a book on how to, it has a lot of part that i wouldnt fuck with you know?
Good sound advice, never saw one crack externally. When I have one rebuilt, I need to supply another case now and then due to internal cracks. Good luck! Bob
GO TO SHOP! The only things back there that would cause cracking are too important to take guesses at. I hope it's under warranty!
You probably have internal problems so it might be cheaper to just get another tranny,could cost you more trying to save a dollar.
He probably has a nasty vibration from either a bent or out of balance driveshaft...bad u-joint or two, a driveshaft at an imroper angle or broken motor or trans mounts. It will happen again if the cause is not detremined.
Guess I am the only one that would do a swap. Not that hard in my opinion. Get yourself a th350 rebuild book and have at it. There is only one special tool that I remember and I made it out of scrap metal in the garage. I think it was for holding the drum the clutch packs were in or something. Can't remember at the moment. Of course this is if it is "OUT" of warranty. Brian
buy a manual and give it a try, post pics on here as you go, make the rest of us on here look like chicken shits for not trying ourselves. http://www.youtube.com/watch?v=D8v66zh8uY4
solid mounts front and rear??? If your using solid or urethane motor mounts DO NOT USE SOLID TRANS MOUNT! In fact never use a solid trans mount EVER. Chassis flex will bust the transmission just about where that one broke. If not using solid mounts,, please excuse my tirade.
My thought exacly! I have never seen a crack (thats broke) there that was not a result of a trans explosion. I know that a "front mount" SBC and a turbo 400 is a bad combo but that cracks the case at the bellhousing. I agree wholeheartedly with moter Pat
I have heard of cases cracking from too much piston-apply pressure forcing the clutches together too hard and splitting the housings. TH350 sometimes had that happen. It is not unusual for a builder to seek out a "4wd trans" case to build with because it has thicker metal cast in certain critical areas. That looks like the low/reverse piston area. Maybe too hard of clamping pressure? Was your pump pressure boosted way up with a spring kit? Modified springs in a modified valve body? Is it a transbrake tranny? Full manual? One important thing to watch out for in a "built" transmission- It is very common for a builder or installer of a "kit" to follow certain manufacturer instructions to drill a passage here, thread-then-plug a passage there, put a stiffer spring here.... Unless you can find the original instructions, you can never be sure the "new" case you put the internals into will be compatible with the parts you are transferring to the new case. You may find that a critical lube passage has been shut off without you knowing where to drill for a replacement path, or other important modifications that have been done to the old case to make the kit work. If you can, please try to obtain the original installation instructions from the maker of the "kit". That will be the only way you will know what you are dealing with as far as case modifications are concerned. I have used kits that tell you to block certain passages in the case, and modify others. You will need to know how to duplicate that in the "new" trans case if you want good results. It can even give you important clues as to what went wrong and why. I will also agree- NEVER USE A SOLID MOUNT!!! No matter how stiff you think your chassis and cage is, ALL frames will flex some. NEVER force your trans case to flex with the car. Let it float a bit as the car flexes.
The more I look at your picture, the more it looks to me like way too much pressure was being sent to the low/reverse piston and it just acted like a hydraulic jack cylinder to push it's way out of the case. Whether your tranny builder is good or not good may not matter for your next step. I am torn between saying don't take it back there because they will only repeat the same improper procedures all over again, or saying DO take it back there because they will likely know where they went too far and can possibly back off a bit to avoid it second time around. If they say it happened before, then they haven't learned yet... I still say they most likely jacked the pressure up too high. That's where the th350'S sometimes split from too much hydraulic pressure applied to the clutch pack.
I bought a TH350 rebuild kit and book and took care of it in one very long night...still not in the car so I may have proper fucked the tranny, but so far as breaking it down and reassembling, it really wasn'y very difficult
dare-to-be-different has a really good point saying that the case you put the gut into may not be stock either. Contact Monster transmission and find out exactly what mods where made to the tranny you purchased. You never said if this is still under warranty or not?
More great info and advice and exactly what I'd expect from the HAMB! Thx! It's not under warranty. All of the mounts are stock but new on a '77 silverado frame. It sits behind a high HP 383 stroker. It started leaking right after a manual down shift and hard acceleration. Probably the driver's fault...
The Jalopy Journal
