Tranny / tcase problem

[DirtyLarry]

Originally Posted by Chevy1TonFun

DirtyLarry you can call BS, but this is the voice of experience. I shatter my trans casing and that was with the frame attachment. I was just giving my two cents.

I still call BS. Voice of a lifetime of experience of 20ish year old guy on 1 single truck? I am sure that your 18” of lift, 40” tires, 468 BB and questionable engine and driveline angles as well driving habits through mud races may not have had anything to do with the transmission case breaking, right?

Sorry but I still harbor suspicion with you from THIS Pirate deal from a few years ago. Post #70 at Pirate. Once you play forum games like that it is hard to recoup yourself with guys older than you that still have good memories.

[vectorit]

Interesting.

[Redcap]

Originally Posted by Chevy1TonFun

DirtyLarry you can call BS, but this is the voice of experience. I shatter my trans casing and that was with the frame attachment. I was just giving my two cents.

You are mistaken.

[Zoomad75]

Originally Posted by Chevy1TonFun

DirtyLarry you can call BS, but this is the voice of experience. I shatter my trans casing and that was with the frame attachment. I was just giving my two cents.

I might be reading this the wrong way, but doesn't that statement just prove what Larry's been saying all along? He shattered his trans case and that was with the frame attachment.

Maybe I haven't had enough beer yet.

[powerdriver 1958]

Looks like we have a difference of opinion ,So lets hold the outside this forum battle down....

However My opinion mirrors Larry's . I run an 84 3/4 mudder 3 years racing in a bunch of pits around Kansas City . 350 turbo and a 205 transfer . No transfer brackets no rods from the mounts.

I beat on that thing hard , from the time the green flag dropped till i run out or the red flag was thrown I never lifted . No problems with adapters , No problem with transmission housings .

1 year and a 1/2 I run it as a long bed , Then as a short bed .

[1972RedNeck]

I will never ever use my truck that hard (I have others for that). I will still get a brace rod. I don't know why.

[powerdriver 1958]

...

Union Star mud run - YouTube

[csb#356]

Originally Posted by Zoomad75

I might be reading this the wrong way, but doesn't that statement just prove what Larry's been saying all along? He shattered his trans case and that was with the frame attachment.

Maybe I haven't had enough beer yet.

I've had plenty of beer but still confused by this

[mud slut 350]

Originally Posted by DirtyLarry

No way. The side bracket creates more problems that it saves, which is why GM quit using on trucks build after ‘72. That is information straight from a retired GM truck engineer. The support rod between the tcase and trans bellhousing is not a bad idea to add but still not required.

Aggreed. on all my K5s that ive had and the k10 i have now never had ANY braces from the t case. Thought about puttin that bar back on when i added the 465 but never got around to it never had any problems with any of them. Then need to flex.

QUOTE: DirtyLarry you can call BS, but this is the voice of experience. I shatter my trans casing and that was with the frame attachment. I was just giving my two cents.

Thats why it broke there was no give between engine, trans, and tcase with ur t case tied to the frame so it gave way at the weakest link a.k.a that adapter with the 4 bolts to the trans without it being tied to the frame the eng trans and t case torque as a whole on the engine and trans mounts. think about it this way. you have a peice of paper write engine on one end, trans in the middle and tcase on the end. grab each end and pull it kinda snug twist the side with the engine written on it simulating torque from the engine, and leave the t case side still simulating it being bolted to the frame. Where does the twisting occure? in the middle or the "trans". now that same peice of paper twist again and let the t case side twist with the engine side simulating it being on rubber bushings and theres no stree in the middle. All the stress goes to the eng mounts and the trans mounts once they bottom out the bushings and set on the solid frame. Now nothing can flex any more than something else its all one solid peice. Hope it helps ya get the picture 1 ton

[lowrollin70gmc]

I'm dragging this back up for another question on NP205 support. Looking for Larry's advice on the matter, knowing his level of experience.

I clocked the 205 behind my Cummins/NV5600 flat with a Trail Tech Fab adapter. At the same time I ordered their NP205 support kit. It attaches to the rear of the case, opposite the front driveline and features a poly bushing. Any opinions on this means of support? It is closer to the center than a stock frame mount and does have a bushing.

Adapter (stock photo, mine is welded up and installed so no good pictures)



Support kit


I haven't welded up the support kit, so opinions are welcome.

[mud.man.rj]

My sm465 in my 71 doesn't have one, glad now, noticed it was missing but my engine is chained to the frame (with 3/4" slack) to help. Got to control the HP.

[lowrollin70gmc]

I'll be about 350 hp / 800 lb-ft once I finish turning up the Cummins. I've held back on playing with the pump until everything else is beefed up and this is one of the last things to do.

[b454rat]

The last truck I built was a 454 4-speed with a later 205. Had 35" tires on it. I didn't beat the crap out of it, but gotta have some fun with a big block stick truck. That didn't have a brace on it. All the trucks I've owned, worked on, stripped parts off of in a junkyard, DIDN'T have that brace. Even with a small block, when you jump on it you can feel the drivetrain twist, shifter can move 3-4" maybe more. If you have that brace on there, the one piece is trying to hold the entire drivetrain from twisting. The t-case itself isn't gonna break, the wee little adapter is gonna take the force of it. I've had some 80s trucks with the 208 that had braces to went to the bell housing, but took them off and still didn't have a problem.

If you want to brace or add some support, that brace shown above would OK. Or some other type, but it needs bushings so it can flex with the rest of the drivetrain.

[argonaut]

This thread is an interesting read. It is true that the T/C torque mount would be the cause of adapter and bellhousing failures.

I do see that some on here have said they weren't used on 73 and up trucks. I'm wondering about the validity of that statement only because my 73 K20 had the mount. Not to say that someone didn't add it on later, thinking it was necessary. I'm wondering when GM truly did stop using them.

Also, does anyone have a picture of what the alternative torque rod looks like? I've never seen this before.

[Redcap]

Originally Posted by 1972RedNeck

I will never ever use my truck that hard (I have others for that). I will still get a brace rod. I don't know why.

It is always a good idea to know why you are doing something.

[jjzepplin]

I ran without that bracket for over ten years beating the he!! out of my drive train with 36" Swampers. I did snap my adapter during a head on 55 mph accident though. When I went to replace it I spoke to a shop that rebuilds t-cases and that's it. They told me the one I had was a weak version. It had a support bearing. They said to get the one without that bearing as the casting was much stronger. I have two now just in case. I have that strut but cannot use it as I have a crawl box. If any one wants it for shipping costs it's free! I will recycle my t-case frame brackets...

[argonaut]

I'll take you up on the strut.

[DirtyLarry]

Originally Posted by lowrollin70gmc

I'm dragging this back up for another question on NP205 support. Looking for Larry's advice on the matter, knowing his level of experience.

I clocked the 205 behind my Cummins/NV5600 flat with a Trail Tech Fab adapter. At the same time I ordered their NP205 support kit. It attaches to the rear of the case, opposite the front driveline and features a poly bushing. Any opinions on this means of support? It is closer to the center than a stock frame mount and does have a bushing.

I haven't welded up the support kit, so opinions are welcome.

Somehow I missed this one back in September. That looks like a nice set up there for hardcore use! As long as the tcase is allowed to rotate with the transmission/engine assembly instead of being tied to the frame, that would work great. Nothing wrong with added beef to connect the tcase to the transmission.

[72BBCK20]

This is an interesting topic, I am currently in the final steps of a 72 K20 build with car 427BBC/NV4500/6 bolt round pattern NP205. the powertrain is mounted to an 86 K30 motor and transmission crossmembers with 86 motor and trans mounts. I also installed the tcase to frame bracket. Should I remove the side T/C mount without adding anything else in place? Is this not to much cantilever weight for the NV4500 aluminum tailhousing? NOW is the time to do something before she's back on the road.

[CrewCab59]

With the 4spd long adapter they tend to be weak to start with.

Those builder t-case supports do more damage than without and mixing poly and rubber.

[Alex V.]

Originally Posted by argonaut

This thread is an interesting read. It is true that the T/C torque mount would be the cause of adapter and bellhousing failures.

I do see that some on here have said they weren't used on 73 and up trucks. I'm wondering about the validity of that statement only because my 73 K20 had the mount. Not to say that someone didn't add it on later, thinking it was necessary. I'm wondering when GM truly did stop using them.

Also, does anyone have a picture of what the alternative torque rod looks like? I've never seen this before.

I have a '74 K10 at the moment that had the T-case side brace. The rear diff. and driveshaft have been replaced, and the trans./T-case mount has been broke clean off and welded back together - being a factory 454 truck, it's easier to figure how this happened than if it had been a 6 cyl. truck all its life, as it is now. I can't say with 100% certainty that the truck came from the factory with the T-case brace, but it sure doesn't look like it was added on. However, the evidence presented here suggesting the driveline is under less stress when the brace isn't there makes sense to me so I'm going to leave it off.

FWIW, originally the truck was a 454/auto (currently has a TH350, not sure if it's original or not) with an NP205 and a few HD suspension options - shocks and front springs, IIRC.

[72BBCK20]

What about making some sort of "pinion snubber" type of bumper on the skid plate just to support the overhanging weight of the 205 on that aluminum nv4500 tail housing?

[gmc 2500 4x4]

glad i found this thread, i just bought new bushing kit for the t/c bracket on my '69 k20 now im thinkin bout leaving it off>>>>thanx 4 this info

[MIKE77z]

Again old threads save patts. Looking around for thr new bushing stumbled me on to this thread . Bracket is stay in the boxes ramjet 350 700r4 205 in a 69 blazer .

[El Dorado Jim]

great info. thanks for bringing up this old thread, I think my son's truck has the brace on it, It will be removed tomorrow!