Ghettobuilt transmission jack

[3gress]

Faced with the problem of replacing one six speed with a lower km box we were scratching our heads figuring how to safely lower, remove and replace the gearboxes without losing limbs to crush injuries.
Being unable to buy or hire a suitable trans jack and with thoughts of a near miss involving a diff, a hand and gravity still fresh in our minds, we set about designing a practical solution.
A quick trip to bunnings saw us leave with a removalist trolley/skateboard looking thingy for around the $25 mark. We had four or five scissor jacks between us and promptly drilled and mounted 3 of them upon aforementioned skateyboard thing to create a succesful homebuilt ghetto style trans jack that not only got the trans change done but also came in handy to lift the engine when replacing engine mounts.




The shade tree solution worked impressively well with us being able to adjust height, angle and tilt without damaging a very pretty Ogura clutch also installed at the same time.
Quite happy to encourage bootlegging the design as long as all royalties be attributed to me and not Keith.

[hks_kansei]

I've always just taken the engine and everything out and just done it on the ground.

Less time on my back under the car.

[3gress]

I'd have preferred to do it the same way, removing engine and trans as a unit and aligning on the floor.
We weren't in a position to use the hoist and leveller though, can't remember why.
I'd not long ago installed my engine and box together and the engine leveller addition on the engine hoist really helped make it easy for a now 40 yr old and 11 yr old to get it done with ease.
Nonetheless this little rig made it all cake moving the box about.

[Mr Morlock]

That trolley will not have much strength. Its only cheap board and probably unrated castors. A proper transmission jack allows car to be on a 4 poster. Seriously if anything goes wrong it is not worth taking a risk.

[Magpie]

That trolley will not have much strength. Its only cheap board and probably unrated castors. Seriously if anything goes wrong it is not worth taking a risk.

It is not as if they will be getting under the trolley!

[3gress]

The trolley has a 200kg rating and performed faultlessly. The recesses in the jacks align to the stiffening ribs on the gearbox and you'd be hard pressed to shake it loose in any position.
It got the job done safely and effortlessly. I'd suggest that validates the proof of concept.
Searching online revealed guys suggesting resting gearbox on their laps and using knees to raise the box in place along with numerous other delightfully unsound suggestions.
We werent going to put trust in something anywhere near dubious in regard to safety.

My partner in crime happens to be a very experienced fully qualified engineer and took the matter seriously. I will leave it to him to comment on the worthiness of the design. Having been involved with such things as designing the original torque tube equipped roll bar that had been offered in the past by a well known mx5 workshop up across the border i had no qualms trusting his proffesional opinion, seeing that it was his car and gearboxes at risk.

[legume]

That trolley will not have much strength. A proper transmission jack allows car to be on a 4 poster

I cant imaging the 6 speed being much heavier than the 5 (which can be lifted with one arm). I did my mx on my back and pulled it onto my chest and lifted it up and in while a mate slid across a 70x 35 pine from one ramp to the other.

That trolley will not have much strength. A proper transmission jack allows car to be on a 4 poster

When you think about it, a 1 tonne car over your head and a transmission balanced on a pole is not really that great. Unless you mean the one on a trolley jack? They are not much chop when you need to roll or tilt.

I welded up a frame exactly the same but with a frame above (one trapazoid suspended above the other with three scissor jacks supporting it and a set of castors). Ive used it over a dozen times and just like you, I found it to work exceptionaly well. On front wheel drive cars I support the engine with an engine crane from the side. On the arm of the hoist I welded some pullies and use a rope to hold the gearbox while I push it away from the engine and the lower it down.

[slomo]

How you did it is similar to how I remove the transmission.
Trolley, scissor jack and timber blocks.
Also a piece of 40x20mm timber across the shifter opening with a rope around the shifter extension housing.

Guide bolts when reinstalling, extra long bolts with head cut off and screw driver slot cut.

[hks_kansei]

That trolley will not have much strength. Its only cheap board and probably unrated castors. A proper transmission jack allows car to be on a 4 poster. Seriously if anything goes wrong it is not worth taking a risk.

The trolleys are pre-manufactured, with the castors attached, and sold for use as moving dollies for shifting furniture etc.

Even the cheapest one at Bunnings is rated to 200kg
https://www.bunnings.com.au/syneco-580- ... y_p3962033

with the largest one rated to 700kg
https://www.bunnings.com.au/easyroll-90 ... y_p3961875


An MX5 gearbox is well under that weight, an MX5 engine weighs roughly 150kg if I recall, and while I can't lift one of those on my own, I can comfortably lift an MX5 gearbox on my own.
if I had to guess, i'd say an MX5 gearbox is closer to 50kg or so.
plus maybe 1-2kg per trolley jack (6kg total)

All up, it's only supporting 75kg maybe, max, with the fluids in the gearbox still.



on top of that, even if the box were to slip off the jacks, it's only going to fall maybe 30cm at most, which while still enough room for the gearbox to damage a limb, if underneath it, some common sense can be used to simply keep a limb out of the way (no different to using a professional gearbox jack, and a 4 post hoist, boxes can, and do, slip from them as well.

[97 MXV]

Because Lismore did not hire out transmission jacks, Dan and I were facing the assisted manhandling methods outlined. So when Dan suggested this idea I loved it.
I loved it even more because it had the specifications of a precise positioning tool loaded to only 5% of the jacks rating and to only 25% of the wooden base and caster rating. The jacks were bolted not screwed down with 2 x 8mm bolts so solid, that the weight of the box could not wedge them apart.

I admit that my pispoor prior planning necessitated Dan to produce this Mother of Invention, this outstanding example of engineering improvisation proven to work because frankly I cared then and there what it could do....it could get me out of a situation.

And yes it could do the job safely and sure enough it worked like a charm and so got me back home to Brisbane safely.
Its simplicity of fit, form and function qualifies it as an improvised work tool rather than a contraption, despite its humble appearance.

Of course Dan has some ideas to enhance safety margins in the case of foreseeable misuse or inadvertence, but nothing has arisen so far as a show stopper for the Ghettobuilt transmission jack.

[greenMachine]

That is a great piece of improvised engineering, well done that man! An inspiration to us mere mortals

I have one of those, or one similar, and I have used it for a variety of workshop-related tasks, but now you have given me another use for it.

That trolley will not have much strength. Its only cheap board and probably unrated castors. A proper transmission jack allows car to be on a 4 poster. Seriously if anything goes wrong it is not worth taking a risk.

"Unrated castors" - oh no, clearly massive public safety issue!

"Seriously if anything goes wrong it is not worth taking a risk", one of the more profound truths from our resident wet blanket, spoken no doubt from the comfort and safety of his bed, because we all know that getting out of bed is a risk, and who knows what might happen if you get out of bed every morning.

[Magpie]

Tone of the more profound truths from our resident wet blanket

[97 MXV]

The additional Jinba Ittai (horse and rider as one), the power of the dream is fittingly celebrated here in Australia, and laid on thick for the hero of the day, Dan with his Ghettobuilt transmission jack.

[Mr Morlock]

A bloke in our club died under a car. Age makes one a bit more wary. I guess the risk is lower car on the ground but take a bit of care guys.

[97 MXV]

A bloke in our club died under a car. Age makes one a bit more wary. I guess the risk is lower car on the ground but take a bit of care guys.

Sorry to hear of such tragic consequences and one must therefore respect concerns expressed. Likewise it is good that younger members are being open about what they are doing also so that ideas for affordable continuous improvement are canvassed.

Assuming the car is properly on rated stands...the Ghettobuilt transmission jack is unable to exert a lift force capable of destabilising the car if say the transmission jams against the tunnel while being raised.
This special safety feature occurs because the jack threads are limp wrist hand tightened only (Operating Instructions must prohibit use of hand tools or strong hands for lifting).

The key safety feature I found was that the stand held the transmission in place for as long as was necessary to ensure the fitup was perfect and engagement gradual and unforced.
In the old days when I was a boy, I recall us under cars without such a handy device shaking and rocking the transmission into place with all our might, culminating in cheers of...Got you you bastard !

I too am old enough to not get under for that, I figured there's gotta be a better way and the Ghettobuilt transmission jack at just $25 or so seemed like the answer.