Confused?

Mod Coupe · tinkerer Joined: 10 Nov 2002 Posts: 56

I bought a gemini 4spd gearbox a while ago for 20 bucks and it didn't come with a tailshaft. My dad went to the wreckers and bought a 4sp tailshaft and it wouldn't fit. So he took it back and got another one whcih also didn't fit.
Finally we went and got one off a five speed which fit perfectly, (it had fine splines, 4sp had course splines).
Any help would be appreciated, can a gearbox be locked out of fifth gear?

Gene FJ20DET · Posted: Thu Jan 09, 2003 11:27 am Post subject: Re: Confused?

got 2 answers,
1) "Don't post here unless you've already done some of the hard yards yourself. Don't post here asking if someone can build something for you. Quite honestly, don't post here if you are a newbie or not technically minded, this forum is intended for technically capable gemini fans to discuss technical issues.

Don't post asking questions about how to fix your car, this forum is for *research* and *development* not to ask about how to change your brake pads or similar.

As part of my current (August 02) policy of zero tolerance, I will delete and/or ban for any breach of these rules.

2) theres no difference with 4spd and 5spd tail shafts. but there are 2 different types, fine and course spline. iv been told that the wagons mostly came with the course due to extra weight being pulled in the back. i dunno if thats true tho
gene
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zzz · petrol head Joined: 16 Jan 2002 Posts: 1298

i was told the fine spline are stronger
zzz

turbogemguy_2003 · rice boy Joined: 09 Jan 2003 Posts: 15

Ive found that a gemini tailshaft IS the strongest part of the drivetrain.Not on is waeker than the other

Gene FJ20DET · Posted: Thu Jan 09, 2003 7:14 pm Post subject: Re: Confused?

i was told strawberry milk shakes are better then chick, but they were wrong Very Happy

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Gold TX Sleeper · backyard mechanic Joined: 05 Feb 2002 Posts: 509

From a technical point of view, the fine spline tailshaft would definately be stronger.

GasGem · backyard mechanic Joined: 05 Nov 2001 Posts: 755

Course Spline - Fine Spline is determined by the output shaft of the gearbox, you must have the matching tailshaft to gearbox otherwise the will not fix.

Early TX 4spd with reverse next to 1st is different again

The standard gearbox and tailshaft config for Petrol tx- te, is Course spline

Diesels and some later tf - tg's were fitted with fine spline grearboxes and tailshafts, these are stronger gearboxes and the diesels also have a cast iron centre plate in the box which is much stronger.

There is also various ratio's avaliable the changes affect 1,2 & 3 gears only all have the same final drive and 5th gear ratio.

Auto tailshafts are different again and should all be the same as the auto box, (Trimatic was the same throughout the range)

Let's hope this clears things up a bit.
Generalisations have been made.

Cheers
Eggy

Ben Wight · backyard mechanic Joined: 04 Oct 2001 Posts: 946

The fine spline output shaft is stronger by design, as there are more splines, so the load is spread out evenly over each spline, the more splines, the less load each one get, thus will take a greater load to brake a fine spline output shaft, than it would to break a coarse spline shaft. Assuming the use of the same materials and heat treatment.

However, my gearbox man has told me that fine and coarse spline gearboxes are the same internally, and the spline is definitely not the weakest part of the box, when has anyone ever heard of someone breaking an output shaft?

Thus, the two types of gearboxes are as strong as each other from the view of their weakest points, the gears I think.

Ben Wight

Mod Coupe · tinkerer Joined: 10 Nov 2002 Posts: 56

Sorry, Next time i will use the general forum.