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Engineers? - Passenger side tcase brace function

GM's design was not a tube design like that one. Gm just used bushings under bolts bolted to the frame. But what if you made a tube bushing like that but faced it towards the frame so as the frame flexed I think you'd be fine. Keep in mind your transmission is still mounted to a crossmember to the frame.
 
with the side mount bracket ( gm ) or bushing ( aftermarket ) you are limiting the flex to much and something has to give .

unless your running a full custom cage mount for the engine and trans and t-case i my self would NOT run the side mount bracket or bushing .
 
yblow said:
GM's design was not a tube design like that one. Gm just used bushings under bolts bolted to the frame. But what if you made a tube bushing like that but faced it towards the frame so as the frame flexed I think you'd be fine. Keep in mind your transmission is still mounted to a crossmember to the frame.
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The idea they finally figured it out is that you want the whole married setup solid and floating on 3 mounts for ultimate flexibility. Anything you can do to reinforce the weak points in the setup, like an aluminum adapter, would make it live longer
 
obijuank5 said:
I think it's there to help take the front to back load off the case like from the driveshaft compressing and extending. There is still a measurable load placed on the case by the shaft and as time goes on, it only gets worse from poor maintenance by the owner.
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I've always wondered about those bars and this makes the most sense of any reason for them I've heard.
 
mrk5 said:
I've always wondered about those bars and this makes the most sense of any reason for them I've heard.
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One thing that back this up, is that they don't use them on gmt400 trucks.
Because the slip on the front driveshaft for the ifs is only for service remove/replace.
 
imiceman44 said:
I have different plans for my cases.
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Yes, if hard wheeling and rock crawling then the factory bracket braces would not be enough to do the job. One of the things I think the factory stock T-case to bell-housing bracket does not address is supporting the weight of the T-case under hard wheeling conditions. That bracket brace is mostly for torsional twist when in 4-wheel drive.
 
Lots of good comments, thanks. I also commented on my thoughts about the relevance of that brace for front shaft length changes in my first post. And I have all braces in place, including 2 inspection cover, and starter for that matter.

I agree on not going from tcase to the frame, it really needs to be locked up relative the the engine/trans/tcase stack so that you absolutely minimize any flexing load on the adapter/tail-housing to prevent it being the fuse. I once broke a transmission in half (right above/behind the valve body) on a waterfall of very bad trail (to get out of broken like that) due to my rear leaf pack collapsing driving the collapsed rear shaft into the back of my doubler (why I went to 4 link on the truggy). You do NOT want to do that, it was nearly impossible to get out with that dead weight vehicle. Although there was an upside. Another wheeler who broke his 14FF rear carrier was able to go back out the next day after we spent half the night swapping my carrier (same gears) into his. :D

Anyway, I agree that an offset will allow it to flex a bit in tensile stress (front shaft compressing). But assuming the front shaft is serviced, I don't think loads will get anywhere near that high. I'm only talking about a 1" offset, so the change in angle is arctan(1 / length), so miniscule, which means the sine of tiny degree is tiny, which means that change in length due to flex shouldn't be appreciably different than a straight bar. Playing a bit loose with the math (ignoring tensile/bending/columnar/young's/etc complexities) , but that's how it plays in my head.

And I'm not completely averse to dimpling to get clearance in both spots if it comes to that. But I wanted to discuss the realities of moving that bar over just a bit before making that call. Doing so would provide the neatest/cleanest solution, as long as it doesn't significantly increase my chances for a busted case/trans...
 
yblow said:
Why not just make something like this ebay item#181313570548 tube bushings with a bracket from were your bar mounts on TC to the frame. You might have to move you exhaust a little, either way your modifying your exhaust. If your real hell bent you can install some mad dawg fender well headers and have all that space wide open on the frame.
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Actually, the header or other options down that line won't work. This is the down pipe of a turbo. However, I could just do a stack out the hood like some of the pullers and drag trucks use. :yikes:
 
BadDog said:
Actually, the header or other options down that line won't work. This is the down pipe of a turbo. However, I could just do a stack out the hood like some of the pullers and drag trucks use. :yikes:
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#hoodstacklife.
 
Definitely helps fight driveshaft thrust. We stripped a K5 one time that took a hard hit on the right front, the guy rear ended a semi on that side. It broke the 10 bolt housing and shoved the whole mess back far enough it shoved the front drive sprocket right out the back of the housing on the NP241. But the 700R4 case and adapter actually lived. Normal conditions create so much potential for driveshaft thrust that it's a good idea to keep it in some form.
 
Well, the deed is now done as of this last weekend.

The bar is offset inboard about 1" and slightly up right alongside the front CV. It's got a rather long overlap (double width) area forming the offset. I don't have the facilities (or knowledge) to run an FEA, but mathematically I really don't see how it would make any significant impact on ability to manage loads from the shaft, even if the slip were to get stiff.

The exhaust down pipe is reworked but I'm waiting on an exhaust band clamp that will be in tomorrow, so I haven't gotten everything back together yet. When it's all in, probably this next weekend, I'll post a pic of the final solution.
 
You know myself and others, @ktmoutfront, have had trouble with the 4 bolts on the adapter to the transmission loosening up repeatedly. I wonder if the support bar would help keep that from happening.
 
mrk5 said:
You know myself and others, @ktmoutfront, have had trouble with the 4 bolts on the adapter to the transmission loosening up repeatedly. I wonder if the support bar would help keep that from happening.
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My factory brace is still there. Bolts still will not stay tight. Cleaned and loctite threads. Over torqued, you name it. Still come loose.
 
I switched mine for high grade (B7 I think?) studs installed with permanent (red) Loctite. Then service grade (blue) loctite nuts with lock washers. Too soon to be sure, but an easy upgrade (in more than one way), and I can't imagine a problem with those loosening.
 
ktmoutfront said:
My factory brace is still there. Bolts still will not stay tight. Cleaned and loctite threads. Over torqued, you name it. Still come loose.
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Darn, thought I was on to something because I've never had that bar on my trucks.
 
ktmoutfront said:
My factory brace is still there. Bolts still will not stay tight. Cleaned and loctite threads. Over torqued, you name it. Still come loose.
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That's weird. I'm curious if you ever measured the male and female fit of the adapter bores. And how was the rotational fitup, was it tight or did it allow a little degree of movement.
 
Loosening fasteners is typically a vibration issue, not a bending/flexing issue of the clamped materials. Switching to studs/nuts should help increase clamp force and be less of an issue.
 
ktmoutfront said:
My factory brace is still there. Bolts still will not stay tight. Cleaned and loctite threads. Over torqued, you name it. Still come loose.
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Guessing yes, but are the bolts long enough?

Accidentally ended up with the wrong bolts on the 14sf diff cover (think maybe I swapped them with ones from a 10b) and they just kept coming loose. How critical would you figure that to be for that application?? But longer bolts solved the issue completely.
 
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