Aussie needs advice

Hey everyone great forum lots of helpful posts but I'm currently designing a lawn tractor rock crawler and wanting some advice on it. I wanted to move the transaxle forward a bit and turn it 90'. run drive shafts to a front and rear independent atv differentials bolted to solid frames to create 2 solid diffs with custom 4 link suspension do yous think the lawn tractor driveline would be strong enough for the job. the front and rear centre diffs I'm using are rated from 200cc to 500cc and both have manual diff lockers will build a custom chassis and shell around the lawn tractor chassis and driveline maybe a mini Willy's jeep so my setup here won't actually have any direct weight on top of transaxle it just has to drive the shafts to diff which are 5.125 ratio being a lawn tractor I can change the gearing with a pully change. Hoping its strong enough thank you for any advice given been planning this for years finally gonna start building. Cheers

Sounds like a very interesting build, I cant wait to see your suspension setup! I would think that as long as you can get the right output speed out of the transaxle it should work, but its probably not gonna be a speedster. You will have to weld the differential in the transaxle as well or theres a possibility that only one shaft will turn and you will loose your 4WD. Also gonna need a few universal joints for the shafts and what not but I'm assuming you already have that stuff. Are you doing a triangulated 4-link? If not you're gonna need pan hard rods for both diffs or they're gonna walk. What are you planing on doing for steering? Maybe a low ratio box would be nice for a rock crawling machine?

I've considered using the tractor diff as trans/xfer case... it will work... problem is the immense gear reduction... when you say crawler, it WILL be... even at 3000 RPM... because of that gear reduction, yeah, the lawn tractor tranny can handle it... if you try to make it faster by putting a higher gear ratio in the solid difs, you may run into a problem... I would suggest an 820 for the trans for the latter... It WILL work... just gotta work out the details

I can have the diff ratios higher at 3.98 or its 5.125 im trying to get it to run like normal ratio obviously abit faster but with minimul strain on drive line trying to work out ratios as the diff centres are 300 each so need to get a rough ratio to work with before I press order I was hoping with some help work it out

AllisKidD21 I'm using atv front and back manual locking differential, shafts, turning joints hubs and 250cc atv front tyres all round on solid frames with triangulated 4-link with vw buggy long travel coilover shocks as for steering I wanted a steering box not entirely sure what I'm gonna get it off any ideas?

Or I was think Suzuki sierra short track diffs but not sure if they'll be to big for the lawn tractor drive line to power them what do yous think it could handle it not fussed on top speed just crawling ability was thinking of making it a 3/4 scale range rover 110 defender swb based off the toylander I'm building my kids and full scale rigs

There's a project that I seem to not be able to find here on the forum but uses the transaxle setup you are describing with it turned sideways and used as a transfer case. It was call, "Not the norm". Was also in one of the buildoffs and is redneckcomputergeek's project. I'm sure it is on his You Tube channel too. To give you an idea on how to do your setup. He finished the project too but with one transaxle for the rear and a transaxle for the transfer case, so he can run driveshafts in a rear wheel drive tractor.

Thank you looks excatly what I've got planned hes gearing is awfully slow thats what im worried about happening I have atv front and rear diff centres priced ready to order geared at 5.125 or 3.89 not sure on what gearing to get that will work better with the lawn tractor drive line though or sierra diff's but again gearing and strength can any shed some light of what gearing I should get?

I would go for the 3.89 gearing. Should get some kind of speed out of the rig. As for the top speed, I can make a pretty good guess. Most of the people here like the ratio 1 to 1 from engine to transaxle and get a good 10 to 15 mph out of the rig.
This would be on your rig that you want to build, would be the output shafts on the transaxle turned sideways with the 1 to 1 ratio from engine to transaxle. Then with the ratio of 3.89 to 1, the top speed would be 2.5 to 3.8 mph in high gear on the transaxle and engine revving at top speed with the governor. Not too fast there. If you want more speed then a bigger pulley on engine would do it.
As for the weak points in the drive line, It's almost always the axles, or breaking the trans housing by hitting it with something, or bearings on the input shaft, or the input shaft casting in the housing. You can build to take care of these things. Like fresh bearings, or building a structure to reinforce the input shaft housing, or an upgrade on the axles with a Doc Locker to where you can replace the axles, or a skid plate added. The transaxle in your setup, there would be way less stress on the transaxle because of the gearing on the diffs you will be adding. Approximately 3.89 to 5.125 times LESS stress on the transaxle. Only time where you will break something would be when you hit an obstacle and everything stops. Very bad when everything stops suddenly. I would guess the axles coming off the diffs would break first then anything before the diffs just because of the ratios from the diffs.

OH, good luck on the build and Welcome to the forum.

Cheers guys ive had a complete change up on my plans ive found 700mm wide solid front & rear diffs geared at 3.89 through the same company in China will run 23/7-10 ATV tyres I'll be running a big bored performance 125cc semi auto 3+R ATV motor with an atv reverse drive shaft to a Suzuki sierra/samurai transfer case geared high range 1.4 low range 2.5 roughly to run both diffs custom chassis/rollcage motor in front was gonna mount the fuel tank in the back and have a small manual fuel pump to keep fuel pressure to the carb not sure what pressure id need yet and was wondering if you had any suggestions on drive shaft ideas? And I was gonna use 400mm atv shocks front and back was gonna use what redlinemotorsports using for up front but unsure about strength and do yous think the gearing will work good enough though I thought the low range gearbox would come in handy for the technical slow terrains I'll have plenty of low range power and all round strength

Your putting all that in a riding mower? Fuel pressure should be about 2 psi. Drive shafts with U-joints for something like this, I would make. I would use the yokes from the samurai cut off the drive shafts and weld them on square tubing. Square tubing is handy for this because if you need the shaft to telescope then you can use square tubing the next size bigger that slips over the smaller tubing, with no side to side play, to have a drive shaft that telescopes. Plus the square tubing fitted in square tubing, you don't have to worry about a spline joint. With the yokes welded to the ends, U joints will be a breeze to get. If it breaks then just make another one.

Nah not a lawn mower as such has turned into a custom mini buggy now after sourcing 125cc solid diffs and can get a big bored 125cc semi auto engine brand new for bugger all here will be fitting race cdi ignition, bigger carb, oil cooler and catch can thought the ratios should be good with whole package and a strong setup high range for speed and low range for the tricky stuff the chassis will be 190x70cm square tube chassis and frame with a custom roll bar I'll be sitting on the floor pan like a go kart and running a samurai steering box as well and I can get a 2psi electric atv fuel pump I was thinking of using the square tubing didnt think to use the original samurai yokes thanks for all the advice aye