Outer Limits 4x4 Board

Hi guys,

I am wondering if anyone has some detailed pics and or designs for changing gear box cross member so it isn't under the chassis??

I will be doing this soon just looking for inspiration as we are competing in tuff truck in 4 months and have bent the cross member really bad.

Also I will be putting twin sticks in my truck and need to remake it anyway

Regards
Mitch

Not a manual gearbox, but that was the reason for doing mine, clearance.

Used trailing arm bushes.

Exactly what I was looking for. Have you got any closer pics? Does it use original mounts? And bushes are they trailing arm bushes? Are they the source of rubber mounting?

Regards
Mitch

Hey mitch. You can see that the mount basically picks up the original gearbox mounts and then as VBanbox said, he has used trailing arm bushes to provide the dampening. One thing you should be very carful of with this type of set up is to have very good underbody protection. If either the mount or the driveline gets hung up on something or gets a good hit from the front then that mount will bend pretty fast. Its great for lateral strenght but not for longitudinal strength. As I said though, that isn't a problem with good underbody protection.

Thanks Toughnut I'm looking on my phone so pics aren't to crash hot can these mounts be beefed up with some triangulation? Also I'm looking at running under body protection possibly some big plates with nylon under it. What's your thoughts on this?

Was wondering if and when your getting home?

Regards
Mitch

Big road trucks use a leaf spring at the back of the gear box to
Hold it up. Could work for u if u make slots for each of the spring to sit
In. Give it a bit of flex if u were to hit it.

unmass wrote:Thanks Toughnut I'm looking on my phone so pics aren't to crash hot can these mounts be beefed up with some triangulation? Also I'm looking at running under body protection possibly some big plates with nylon under it. What's your thoughts on this?

Was wondering if and when your getting home?

Regards
Mitch

I'll be home just after the 19th. The cab will be off my shorty too if you want to drop by and see what you're up against. I don't have a custom mount done yet though. I'll be starting the fab work on my truck this break.

Thanks toughnut keen to get a hold of this shorty I'm using it to fix the tuff truck up now. Only have 5 months left.

Regards
Mitch

No worries mate. Got stuck up here an extra week than I though I would. Can you send me your email again and I'll get the pics to you. Give me a yell if you need a hand.

Its mitch@mitchellbros4x4.com.au do you mean give you a yell to help fix the tuff truck? We are sponsoring Team Juzzy and panel damage is quite substantial it needs b pillars etc. I'm there this weekend rebuilding front end than pulling rear locker for some inspection. Hoping to get the body sorted so we can build an exo cage

Regards
Mitch

I made this one out of Bisalloy.

It still uses the original mounting holes so i made some sliders for the bolts with high tensile bolts.

Still gained about 25mm clearance.

I made this when i lifted my driveline 50mm

Looks like a good cross member. I need to see if anyone has made one that sits flush with chassis. So I can belly plate it.

Regards
Mitch

Getting that extra 10mm of clearance is not as important as having a nice smooth and large belly plate. When I say smooth I mean smooth front to rear so eliminating hang up points like the gear box cross member. A few people use a nylon plate on the underside but this is really only used for winch trucks because it slides on the mud easier in competitions and doesn't get that suction effect that flat steel gets.

Also have an angle on the leading edges so that if you hit something it will slide up over it a little easier instead of a flat edge. I've seen some really good belly pans and some not so good ones. Its best to have the car off the ground so the diffs are at full droop when you plan your belly pan as well so you can accomodate for the drive shafts. This is also a big consideration for the front shaft when building a gearbox crossmember.

Your gearbox crossmember, lower rear trailing arm mounts and slider mounts are all good areas to mount the belly pan from. You can also weld angle iron to the chassis to give you extra mounts. Just remember that these mounts pretty much only need to hold the weight of the belly pan because if you have it mounted so it touches the chassis rails it will transfer most of the impact to the chassis and not the mounts.

A little off track but needs to be considered when you are designing your gearbox crossmemeber. Hope it helps.

Yeh good point toughnut that's what I am trying to achieve is a big flat belly pan with nylon the width of the vehicle. I have a few questions is it ok to just have a slot cut out for the front tail shaft? I'm running twin sticks soon so will I need to have a gear box and also transfer case mount?

They make it a fair bit longer with twin sticks. I have a few pics ill upload at work tomorrow of some mounts and if you could let us know what you think as fab work will need to be started soon.

Also anyone know of a cheap place to get nylon sheets? And how thick should the nylon be?

Regards
Mitch

The nylon sheets I've seen have been 10mm. I have a couple of ideas for the mounts that you need to make. You'll be running the drive shaft from the second transfer so it may be better to make a crossmember that loops over the top of the shaft rather than below it. You can also do this on the transfer case mount by using a plate type mount picking up the bolts through the casing on the transfer. This method is pretty common for any vehicle that is hard mounting the drive line like drag cars but you can still use this method with a rubber mount at the chassis side of the mount.

Yeh 10mm sounds good. I sort of knew I needed a mount to loop over front shaft. Shot you ideas via email if you want and ill have a look and hopefully start fabricating soon

Regards
Mitch

This is the belly plate I made before my engine conversion.

http://www.outerlimits4x4.com/viewtopic ... 7&start=60" onclick="window.open(this.href);return false;

Now looking into something flush with chassis as I have gained a heap of clearance.

Here is a few pics from twins on Bartso's gq tuff truck.

Also vanbox is your slide plate removable?

Pleas comment any info is good info





Regards
$itch

Yeah. See how he has picked up the bolts on the transfer case to bolt to the mount? There is going to be a lot of torque on that transfer becuase of the gearing that is why he has strengthened it so much. I believe you could make it sit a bit higher though. If you ran the plate over the top of the transfer case (depending on space) then you could do away with the bar going across the bottom and you could basically flip the chassis mounts so the transfer case is the lowest part at that point. If you are going to mount it like that then you could do what I did with my belly plate the first time I built my truck and run box section from one slider all the way under the chassis to the other slider. This does take an inch or so away from your ramp over height but it makes everything way stronger and you don't have to worry about custom mounts because you cover all of the mounts underneath. When I did this it coverred my gearbox crossmember and I only lost about 10mm of total clearance but I had a nice flat surface underneath and didn't have to custom make any mounts. It all tied in with my roll over protection on the tray so it was very strong.

[quote="toughnut"]Yeah. See how he has picked up the bolts on the transfer case to bolt to the mount? There is going to be a lot of torque on that transfer because of the gearing that is why he has strengthened it so much. I believe you could make it sit a bit higher though. If you ran the plate over the top of the transfer case (depending on space) then you could do away with the bar going across the bottom and you could basically flip the chassis mounts so the transfer case is the lowest part at that point. If you are going to mount it like that then you could do what I did with my belly plate the first time I built my truck and run box section from one slider all the way under the chassis to the other slider. This does take an inch or so away from your ramp over height but it makes everything way stronger and you don't have to worry about custom mounts because you cover all of the mounts underneath. When I did this it covered my gear box cross member and I only lost about 10mm of total clearance but I had a nice flat surface underneath and didn't have to custom make any mounts. It all tied in with my roll over protection on the tray so it was very strong.[/quote

Thanks dude I am going to try and make a mount of the second transfer that picks up on a few bolt holes either side. As far as space over the transfer I don't think it will be an issue being twins it should be behind my cab. When its a ute anyways.

I would be keen to see your belly plate if you have any pics or build thread. I need it to have a flat belly plate with nylon on it so I will loose some ramp over but hopefully the nylon will allow it to slide.

Regards
Mitch

The nylon is really only good in mud. It doesn't make that much of a difference on rocks and stuff. It'll just be a little quieter when you're scraping over rocks.

I was told that it helps the ramp over issues and allow the car to slide. But I suppose that is so long as its flat. Keen to get started on the twins. I wouldn't mind seeing a few belly plates on patrols.

Regards
Mitch

This is the best image that I have left of my old belly protection. I ran 40mm box from the slider on one side right across under the chassis to the other side. I lost a little clearance but it was massively strong and saved my truck from a whole lot of stuff.

Lifting driveline? as in lifting the gearbox higher and engine etc? That would put the COG out and mess up the whole geometry of the truck I'm thinkinZ

morewheeldrive wrote:Lifting driveline? as in lifting the gearbox higher and engine etc? That would put the COG out and mess up the whole geometry of the truck I'm thinkinZ

Who's talking about lifting the driveline? Just talking about running the mount over the top of the transfer case so it doesn't hang so low below base of the chassis.

Was your belly pan removable without removing sliders? Also will I need a gear box mount and a rear transfer mount?

Regards
Mitch

The rear transfer mount does hold some of the weight but it is more for controlling the torque that is going through the transfer to stop it twisting and snapping the adapter bolts. Thats why a mounting plate set up would work better picking up a number of case bolts. You still need the gearbox cross member to hold the main weight of the driveline and to a lesser extent to help control the torque. The belly pan on that pic above wasn't removeable without removing the sliders but it wouldn't be hard to make it that way. I just had cut outs to access the drains and refill points. It wasn't hard to remove the sliders though. 24 bolts. Took about 25mins to remove. A bit longer to put on but not much. All of the bolts were easy to access and adjust.

Yeh I might start designing the case mounting of a spare case I have. As for the gear box cross member I may need to have a good look at how I can achieve a mount that goes above the drive shaft.

Then I will start the sliders and belly plates I may stick with welding some angle to mount the slide plate.

Regards
Mitch

toughnut wrote:The nylon is really only good in mud. It doesn't make that much of a difference on rocks and stuff. It'll just be a little quieter when you're scraping over rocks.

It makes a BIG difference on rocks! With it being smooth and slippery you wont get hung up on the rocks and even if you belly out it doesnt take much to drive off.
Have a look under most tuff trucks or buggys

I actually talked to toughnut a bit before making mine. Based it loosely from his suggestions and pics.

Sliders were welded together with 40mm SHS, the plate then bolted to the ladder frame. When the gearbox/transfer needed an oil change, the plate was dropped for access, thoroughly cleaned and repainted before fitting back up. Again only lost about 10mm clearance overall, but gee the truck became invincible! Saved me many times.

Going to get something under the allison soon, as it is quite vulnerable.