Gear Box --(Todd)

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Ok people, big problem...
I have very noisy gear box bearings, and also the extension housing seal is leakin...
I have been told this may cost up to $800 to recond the GBox...
so... I think a good 2nd hand one will be in order, but I have choices... should I get (and what are the differences between):
Gemini 5 speed
Gemini 5 speed (deisel)
Rodeo 5 speed
Magna 5 speed

Apparently the Magna box goes like a rocket?? yes? no?

Any info on other boxes that people know of would be appreciated...
thanks

Todd

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Apparently the 4 speed gem boxes are slightly stronger than the 5, but if you can find a 5 gem speed gearbox that makes no noise in 5th and changes gears easily then good for you, personally i have been through at least 5 gem 5 speeds and none of them have been perfect, maybe im unlucky but at the end of the day, those boxes shit me up the wall (i guess they have done pretty well though seeing there about 20 years old) Rodeo and at some debate the diesel gearboxes have a closer ratio, i believe gears 1-3 so you will get to a lower speed quicker. Magna 5 speed will probably require a custom bell housing i believe (haven’t had any experience with them but i would imagine the chance of a magna box bolting straight up to an izusu engine lies somewhere between SFA and none) As for them going like a rocket, well thats going to depend on how much torque your motor puts out, if the gear ratios of them is much lower and your engines crap then it would probably go like a dog trying to turn the wheels. Personally i feel the gear ratios of the gem boxes (or the diff) are set far to high and too much shifting is involved before getting to any decent speed. If your going to go as far as getting a custom bell housing then i would probably go for a celica 5 speed.

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Magna 5 speed? I thought all magnas were FWD therefore fitting them to a Gemini would be impossible..

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Gemispares Drag car has a mitsubishi 5 speed (Magna I'm sure)

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I am building an engine which will have EFI and should have 10.5+:1 (hopefully... never can tell till ya finish these things)
so I want a box that is gonna be able to utilize huge power and go like the clappas... getting a bell housing is fine... don't give a shit... but apparently there is a magna that bolts on... at least that's the impression I got from Dennis at Gemispares...
correct me if wrong....

Todd

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There might be a mitsubishi box that might bolt on with a bit of work, but I also cant imagine a mitsi box bloting onto an isuzu engine. I would also think that it would have to be a sigma box, as I though all magnas were front wheel drive.

I would just stick with the standard box. I have been using the same 5 speed for the past 5 motors, and only now have I got another second hand one that is in good nick, as the old box was getting bad gear wear. The 4 and the 5 speeds were identical I thought, its just that the 5 speeds have an extra gear cluster, which is a bit weaker (5th gear). But If you dont go crazy in fifth all the time, they should last as long as a 4 speed.

I really dont think you are going to have any troubles with a standard box. I have had around 250hp going through my 5 speed, and it hasn't blown up or anything. I feel that it started to get gear wear becasue I ran it for about 6 months with less than a litre of oil, due to a extension seal leak. You can get larger bearing put into them if you are worried, but I wouln't be.

With efi and 10.5:1, even with every other typical mod like good head, big cam, good exhasut sytem, and say a 2 litre bottom end, you will only be pushing out around 130-160hp. Of course some engines get more, but then you have to spend up big on a great head, more compression, bigger cam, and a great bottom end. Its very hard to make huge power by compressing an intake charge at atmospheric air pressure.

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magna? possibly. i though you could put corolla 4 speeds in or something like that, there suppose to be pretty strong (think it was corolla?) 10.5:1 should be able to turn a lower ratio fairly easily. i think the input shaft is pretty much the same and doesnt need changing or needs little mods but dont take my word for it. otherwise get a 3.5 diesel diff. the difference over standard between:
43km in first @ 6500rpm to 49km
76km in second @6500 to 85km
117 in third @6500 to 131
166 in fourth @ 6500 185
194 in fifth @ 6500 217
..so it makes a little difference but not a hell of a lot. At least you can get it off the clock.

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Ok thanks, I might stick with the Standard then although I use 5th around the city all the time aswell... I should stop doing that

G180 with flat tops, efi with Injec Computer (Full Engine Management), 1600 head (not sure what's been done to it yet) Stage 5 cam, extractors 2" Magnaflow at the ass with 2 1/2" tip, obveously no pollution shit..

hopefully that will give us a little power (rather than the super-duper turbo charged 40 of a stocky)

thanks for the help.

Next thing is:
DOES ANYONE HAVE A VERY GOOD 5-SPD Gearbox they want to sell???? (probably not, but worth a shot)

Todd

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Thanks for the help...
I might go for a Deisel Diff, but have also been thinking about an LSD, however, once the dash is all done, it won't be goin off the clock unfortunately... the speedo has a 260KPH dial, but hey, least I can get it off the dial in the mean time!!!

So next question, how good are the LSD's compared to the deisel diffs or is that dependant on where and what I get it from also???

Thanks

Todd

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what computer are you using?

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the lsd will help you accelerate much faster as its much harder to spin 410mm of tyre as opposed to 205's (if thats what your using) as with the single spinner (diesel and stock diff)also added bonus of being heaps more fun in the wet and much better circle work

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errrrr Mine....??!!??

Todd

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It's an Injec- computer... I'm not sure of the model, but it's the better one (lol... duh) I'll get the model on Monday when I see it next (I figure if everything to do with the car is left with the car at the panel shop... and plus it's all covered by their insurance then)

Todd

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Couldn't be.. Theres no way a FWD gearbox is going into a RWD gemini
Sigma maybe?