Post-SAS crossmembers

[CronusTRD]

Where have you guys added crossmembers post-sas?

I just added the FROR crossmember and cut out my stock t-case crossmember, and aside from some new vibrations, the truck doesn't feel as stable. Right now my frame goes: front hanger/crossmember, engine, FROR crossmember, rest of stock stuff. I'll be adding a hard mounted crossmember where the old swaybar was, as well as a removeable crossmember behind the radiator to add a guard for the radiator.

[fastrexxx]

In these pics, I hadn't yet cut off the old crossmember;

[fastrexxx]

'Course, if you ran a piece of 3"x3/8" plate from sway bar mount to sway bar mount, that'd probably stiffin things up too. The FROR x-member doesn't really tie the frame rails together (because of the bushings) as good as a solid x-member.

[CronusTRD]

I cut off the stock swaybar mounts so I need to make some new brackets :lol:

I still have to added a crawler so I'm using the FROR crossmember for now since it will be easy to move back. Once that's in, I'll add a more permanent crossmember underneath the transmission pan/transfercase

Aren't you worried about stress cracks on the t-case from that crossmember? Or is that a soft bushing?

[fastrexxx]

Not hard mounted. It's a poly GM car transmission mount. Just enough flex without ripping (like the rubber mounts).

[sloppyslim16]

The mounts are fairly soft. When I put the FROR xmember in I noticed a lot more vibes. The one thing that has helped has been the exo cuz it made the entire frame super rigid.

['00Tacosinger]

Originally Posted by fastrexxx

In these pics, I hadn't yet cut off the old crossmember;

do you have any detail pics of the bushings you are talking about?...can't see anything but solid steel in those pics.

['00Tacosinger]

Originally Posted by CronusTRD

Where have you guys added crossmembers post-sas?

I just added the FROR crossmember and cut out my stock t-case crossmember, and aside from some new vibrations, the truck doesn't feel as stable. Right now my frame goes: front hanger/crossmember, engine, FROR crossmember, rest of stock stuff. I'll be adding a hard mounted crossmember where the old swaybar was, as well as a removeable crossmember behind the radiator to add a guard for the radiator.

I ran that way for a very short time...until I got my center xmember bolted back up (mounting platform for the rear of the tcase skid). The frame flex was kinda wild

now I've got: front xmember boxing the front of the frame, AP xmember behind the radiator, tranny/crawler xmember, center xmember behind the tcase.

[fastrexxx]

Originally Posted by '00Tacosinger

do you have any detail pics of the bushings you are talking about?...can't see anything but solid steel in those pics.

['00Tacosinger]

pic not big enough

cool, thanks. what made you think of using that mount? great idea.

[fastrexxx]

Price/availability. I had to make the crossmember from scratch, so I figured why not. Having the mount in the middle like that means less driveline vibes too. It's worked out well, except for the first two that I ran ripped apart pretty quick. I switched to a poly mount and life has been good.

[Shefron]

Originally Posted by fastrexxx

In these pics, I hadn't yet cut off the old crossmember;

Are you going to add a skid plate for the transfer case?

Looks like a very good place for rocks to hit on.

[Dickfoster]

To tell you the honest truth I think there are several problems with that setup.

['00Tacosinger]

Originally Posted by Dickfoster

To tell you the honest truth I think there are several problems with that setup.

well heck, don't leave us in suspense....list them

[fastrexxx]

Originally Posted by Dickfoster

To tell you the honest truth I think there are several problems with that setup.

I'm open for ideas.

And no, I have not yet made a skid plate for it. I don't really want to either. I'm holding out 'til I swap over to dual 4cyl cases.

[TacomaJoe95]

Just build something like this and call it done. No cross members just one big ass skid plate is all you need.

[Dickfoster]

For starters.

#1 With just a single bolt per side, that crossmember isn't doing a hell of a lot for frame stiffness.

#2 No skid plate for the bottom of the tcase which is made of cast aluminum and prone to bust wide open on the rocks.

That's enough to say it isn't well thought out but if that isn't a tranny mount I see there are lots of other problems.

#3 Mounting the T Case to the crossmember with bolts and bosses not meant to carry that kind of load. All those bosses are meant to do is hold the case halves together. Without a something to add some give under torque the bosses will tend to fracture over time from the repeated stress from the torque of the driveline since the bosses are in shear. I simply can't figure out why people keep doing this when there is a perfectly good place to put a tranny mount that is made for the job and do it up proper by putting the retention bolts in tension like they should be for cast aluminum.

#4 All that complicated shape cutting seems to be going out of the way to make it hard when there is a purpose made mounting location.

#4 Lack of noise isolation between the drive train and chassis. It's gonna sound like shit inside that cab when it doesn't need to. That's another part of what tranny mounts bring to the table. I'm also guessing that this truck has a body lift making the situation all that much worse. As you probably know I've always thought that body lifts were just about as stupid as weld-on sliders. But that's just me I guess.

#5 There are other potential problems depending on what the end product is going to be but I think I've listed enough for now.

[Dickfoster]

Now that's lookin pretty damn good. Maybe a tad heavy but bullet proof, thats fer damn sure. Unless he's going to mount some suspension links to it or something that is.

It just wouldn't do to need to remove the front suspension just to swap a clutch or yank a gear box for service. You'd be looking pretty silly in that case.

['00Tacosinger]

Originally Posted by Dickfoster

For starters.

#1 With just a single bolt per side, that crossmember isn't doing a hell of a lot for frame stiffness.

#2 No skid plate for the bottom of the tcase which is made of cast aluminum and prone to bust wide open on the rocks.

That's enough to say it isn't well thought out but if that isn't a tranny mount I see there are lots of other problems.

#3 Mounting the T Case to the crossmember with bolts and bosses not meant to carry that kind of load. All those bosses are meant to do is hold the case halves together. Without a something to add some give under torque the bosses will tend to fracture over time from the repeated stress from the torque of the driveline since the bosses are in shear. I simply can't figure out why people keep doing this when there is a perfectly good place to put a tranny mount that is made for the job and do it up proper by putting the retention bolts in tension like they should be for cast aluminum.

#4 All that complicated shape cutting seems to be going out of the way to make it hard when there is a purpose made mounting location.

#4 Lack of noise isolation between the drive train and chassis. It's gonna sound like shit inside that cab when it doesn't need to. That's another part of what tranny mounts bring to the table. I'm also guessing that this truck has a body lift making the situation all that much worse. As you probably know I've always thought that body lifts were just about as stupid as weld-on sliders. But that's just me I guess.

#5 There are other potential problems depending on what the end product is going to be but I think I've listed enough for now.

The Dick has spoken...

[Dickfoster]

Well he did ask didn't he? LOL

[fastrexxx]

Originally Posted by Dickfoster

For starters.

#1 With just a single bolt per side, that crossmember isn't doing a hell of a lot for frame stiffness.

Well, it's kinda spliting hairs (and I'm no engineer), but the thin factory "U" shaped x-member seems a whole lot weaker than the 2"x2"x.25" x-member I replaced it with. One bolt on each side is all you need. It works fine for what it is.

Originally Posted by Dickfoster

#2 No skid plate for the bottom of the tcase which is made of cast aluminum and prone to bust wide open on the rocks.

I've already addressed this concern. See above.

Originally Posted by Dickfoster

That's enough to say it isn't well thought out but if that isn't a tranny mount I see there are lots of other problems.

It is a transmission mount (poly).

Originally Posted by Dickfoster

#3 Mounting the T Case to the crossmember with bolts and bosses not meant to carry that kind of load. All those bosses are meant to do is hold the case halves together. Without a something to add some give under torque the bosses will tend to fracture over time from the repeated stress from the torque of the driveline since the bosses are in shear. I simply can't figure out why people keep doing this when there is a perfectly good place to put a tranny mount that is made for the job and do it up proper by putting the retention bolts in tension like they should be for cast aluminum.

My thinking (again, I'm no engineer) is that there are 7 or 8 bolts that hold the plate on to the case. The plate somewhat strengthens that section of the case. Torsional shear is a non-issue because the poly trans mount will allow the same movement as a factory mount.

Originally Posted by Dickfoster

#4 All that complicated shape cutting seems to be going out of the way to make it hard when there is a purpose made mounting location.

I wanted my drive line mounted higher (flat belly). If I had used the factory location in conjunction with the 2x2 crossmember, the t-case would have been through the floor, even with the "then installed" 3" BL. I had the materials, a friend with a plasma, and an idea. Just thinkin out of the box, I guess.

Originally Posted by Dickfoster

#4 Lack of noise isolation between the drive train and chassis. It's gonna sound like shit inside that cab when it doesn't need to. That's another part of what tranny mounts bring to the table. I'm also guessing that this truck has a body lift making the situation all that much worse. As you probably know I've always thought that body lifts were just about as stupid as weld-on sliders. But that's just me I guess.

Again, there is a poly trans mount in there. It just looks solid mounted. And I agree with you, body lifts are dumb. I have since removed it and cut up the floor for clearance for the t-case. It's nice being lower.

Originally Posted by Dickfoster

#5 There are other potential problems depending on what the end product is going to be but I think I've listed enough for now.

I appreciate your thoughts. I put that t-case in there knowing it was going to be temporary. I'll eventually have dual 4cyl cases in there and will have to redo everything. For now, I'll wheel it 'til I'm ready to wrench on it again.

['00Tacosinger]

Originally Posted by fastrexxx

I'll eventually have dual 4cyl cases in there and will have to redo everything. For now, I'll wheel it 'til I'm ready to wrench on it again.

what the heck are 'dual 4cyl cases'??

Oh, and he is an engineer so be prepared to be flamed

[fastrexxx]

Originally Posted by '00Tacosinger

what the heck are 'dual 4cyl cases'??

Seriously?
Dual tranfer cases, dual t-cases, whatever you want to call them. RF1A gear driven transfer case from a 79-95 4 cylinder Hilux. Going that route to replace the single VF1A chain driven case that's in my truck now.

Like this:

Originally Posted by '00Tacosinger

Oh, and he is an engineer so be prepared to be flamed

I figured as much. I'm familiar with The Flaming Dick. I know deep down inside he's just trying to be a nice guy, but always comes across as a grumpy old fart.

[Dickfoster]

I think you must be one of those folks they call an idiot so I'll waste no more time than this on you.

The fact that you're no engineer is painfully obvious. Therefore that was a very true statement if not an understatement. Kudos for that.

A single bolt allows twist. It's not a strength issue or I would have simply said to get a bigger bolt. It's simple mechanical design precept. Were you not paying attention in geometry class when they were talking about triangles and such? I am assuming that you completed high school but maybe I should not assume as much. My bad

I prefaced everything after the second point with (IF) THAT IS NOT A TRANNY MOUNT I SEE (THEN). Therefore everything you typed in responce to points 3 forward is just a waste of bandwidth. In future, I suggest that you concentrate more on quality not quantity. Don't you know that wasting bandwidth contributes to global warming.

[generalee7]

Fastrexx, add this gusset. You'll benefit greatly later on when it doesn't bend on you. Butt welding angle iron to flat plate is not going to last long at all unless its something 3/8" + thick.



It's a little odd that you went through all the work to build a good mount on the transfer case then just used a similar bushing to the stock one. It kind of negates itself since you probably get the same amount of twist in the drive train with that setup than you do from stock.