How to Convert an Auto Gemini to a Manual

[tobytj]

Auto To Manual Conversion For A Gemini

Parts List

 Manual Gearbox and shifter (Note that for a TX model the manual gearbox is different to other models. The rear mountings are different.)
 Tail shaft to match gearbox – check the spline as there are 3 different types. Some 5 speed gearboxes will match the auto spline but auto tail shafts are too long.
 Rear gearbox rear mounting and plate? Not sure, might be the same as auto – should come with your gearbox anyway.
 Flywheel. (6 bolt for a G161 motor and most G180 and G200). The bolts holding the auto drive plate to the crank will fit the manual flywheel.
 Spigot bearing (autos don’t have these but the recess in the crank will be there).
 Clutch plate and pressure plate and thrust bearing, bearing carrier, fork, fork rubber boot and return spring.
 Clutch cable – preferably with steel and not cast ends
 Gear stick/shifter
 Speedo cable? I think the auto cables are different at the gearbox end.
 Rubber boots for floor opening and top of shifter
 Manual console unit with a vinyl gearstick boot. (You don’t need the whole console, just the manual centre insert to replace the auto one)
 Manual pedal assembly with a clutch pedal
 Vacuum connection to manifold from brake boaster (optional or block off surplus hole on the auto one)
 If you are fitting a 5 speed from a shuttle or rodeo that was set up for a hydraulic clutch you will need the clutch fork, rubber dust boot and return spring from a Gemini 4 speed. Relocate the pivot ball to the optional location on the input shaft retainer (easy as) to suit the cable clutch fork. The shuttle /rodeo box should have the bracket for the return spring even though it is not used for a hydraulic clutch.

Removal

Remove tail shaft and let as much of the fluid as possible drain out.
Disconnect pipes to radiator – don’t worry water won’t come out and the auto radiator is fine for a manual.

Remove all the normal bits and take the engine out of the car – changing the transmission in the car is a bit like climbing Mt Everest – it is possible but….

When removing the auto the book says the torque converter should not be separated from the box. Slide the auto off the block 50 mm and undo the bolts holding the torque converter to the drive plate. Remove the torque converter and box as one unit. Remove the drive plate from the crankshaft.

Gearbox Prep

Remove shifter (3 bolts) and put a rag in the hole to stop debris getting in. Lightly grease the clutch pivot, thrust bearing carrier and input shaft spigot.

If thrust bearing is noisy or if you are fitting a new clutch – replace the thrust bearing. You don’t need a press just position the bearing on top of the open jaws of a vice, use a slightly smaller socket as a drift and belt it out – note the position of the front and rear of the bearing and it the right way round. Use the vice to squeeze on the new bearing or tap the carrier on.

Check uni joints in tailshaft. Replace if worn.


Assembly

Fit spigot bearing and grease it a little in the centre
Fit flywheel and torque up bolts.
Fit clutch – use an aligning tool or make sure the gap between the outer edge of the clutch and outer lip of pressure plate is the same all the way round. It has to be spot on.

Bolt up gear box. If it won’t go then check clutch alignment. Some resistance is not unusual while sometimes they slide up easy. Use longer M10 bolts retaining bolts to guide the gearbox into place for the last 50mm.

Body Mods

Discard the rubber plug on the tube that the clutch cable slides into. Wind in the adjustment of clutch cable all the way. And fit into tube in firewall

Change the pedal assembly. Simple bolt out /bolt in. Before you bolt in the manual pedals, connect the clutch cable over the hook on the pedal end. It is a cow to fit otherwise.

Change speedo cable. It can be done from underneath but otherwise detach the instrument cluster and pull it forward (for TX to TE remember to undo the wing nut on the back of the instrument cluster).

Change or modify the vacuum connection on the inlet manifold by blocking off the auto vacuum connection.

A new opening is required in the floor tunnel and the old opening for the auto should be blocked up. Welding a plate over the old opening is best – pop rivets second best. The new opening has to be exactly right so the rubber boot will fit.

Make a template out of piece of cardboard using the body of another manual gemi if available. Alternatively, (but I have not done this myself) use the rubber boot as a template and reduce the opening size all round by the depth of the lip in the rubber. To locate the shifter opening uses the two pre drilled floor holes for the console front mounting bracket as a reference. Measure the distance back from these holes to the shifter opening on another manual.

Use a jig saw to cut the opening for best results.

Electrical

The auto shifter has a cut-out switch for the starter motor to prevent starting with the transmission is in drive. Find the two wires that attach to the switch and permanently join them and insulate the joint.

Locate the reversing light connection under the vehicle – you will need to join this up after fitting the engine and box.

Don’t worry about the different electrical on the carburettor. Auto carburettors don’t an enriching solenoid but you don’t need it.

Make sure you connect up the brake light switch when you change the pedals. Don’t worry about the switches on the clutch or accelerator pedal. Test brake lights.

Fitting

As per normal engine fitting.

Once you have the tail shaft on, place 1.3L (4 speed) or 1.6 L (5 speed) of 30/40 grade engine oil down the shifter hole before fitting the shifter. Don’t use 90 grade gear oil or second gear with crunch. Make sure the box is in neutral and the selectors are all in a row (look into selector hole) before fitting the shifter. It is possible to lock up one of these boxes by selecting two gears at once - but rare!

Fit clutch cable. It passes through the right engine mount bracket. Adjust up clutch cable by hand till there is only a little bit of slack before the thrust bearing engages. There must be some slack so the thruct bearing clears the pressure plate when clutch is engaged (i.e. foot off the pedal).

Couple of Hints

 Good idea to fit a new seal on the back of the gearbox where the tailshaft slides in.
 If gearbox was leaking in donor car replace the rear oil seal.
 I would always fit a new clutch kit and new uni’s on the tail shaft – but if I was young and real short of cash only if probably wouldn’t.
 Shortening the shifter by 50mm is good - any shorter is horrible.

[Twin_Weber]

the gearbox difference is only a problem on the early tx models

[mrcala]

thnx 4 the help have it back on the road goin to get it tuned next week ready 4 sum cruzn

[tobytj]

Post script - parts.
-The auto rear engine mounting is totally different to the manual. (thats the plate with four slots in it and a rubber mount with a single bolt that connects to the gearbox)

- If you use a G200 flywheeel it uses a different clutch to a G161 (bolts spacing a bit wider and clutch a slightly larger diameter). Alternatively you can bolt a G161 flywheel to a G200.

[gemis_rule]

one of my mates is about to do this and asked me these questions as all my geminis are manual i didnt know so i am asking you lot for him.

1 : how much would expect to pay for all the parts
2 : how long would you expect the conversion to take
3 : how much would it cost to get someone to do it


cheers for any help
_________________
- tg race car -
- tg road car ( stock as a rock ... for now ) -
- td wagon project - sold -
- on the wagon hunt again -

[BallaratOldLady]

My TE appears to have been born an auto and has had the change.

Her starter motor is not as good as it could be, the sparky says that the cog bits (mental blank for technical term, sorry) that engage with the drive plate have worn unevenly, he is willing to bet that the drive plate in the original auto was slightly different to the current one.

Does his theory have any merit?

[Encyclopedia Ronnie]

he verry well could the plate that bolts 2 the motor on my auto and on my manual were different when i did the conversion i did swap them over n havnt had dramas yet the way the startor bolts up is a bit different in auto n manuals 2

[cammo]

Hi guys i have just done this conversation, and im new to the land of gemini's.
i took the engine and gear box out replace the auto with a 5 speed manual. replace the spigot gearing, clutch, pressure plate and thrust bearing.
Put the engine back in.
It now runs really s*#t (guess its just the timing because now there is a flywheel on the engine.)
but my big problem is that when i take my foot off the clutch pedal and the box is in neutral it wines and doesnt sound good at all..
Have i done something wrong or is the box stuffed?
Cheers

[Gemi Coupe]

its probably the front bearing in the gearbox, or the thrust bearing.
they are known for making nasty noises.

as for not running right.
Did you check all your vacuum lines to make sure they are connected as they should be?
There is one that normally goes from the back side of the manifold (near the line for the booster) down to the vacuum modulator on the side of the auto trans.
Is that blocked off?
_________________
reprezentin in the wags....

[cammo]

Oh ok well i replaced the thrust bearing.. and i didnt think that the trust bearing would be making contact with my foot off the clutch.
I am thinking it is the gearbox..
and yeah hi have blocked that one off.. and i think all the others are connected. it just sounds like the timing is out..

[johhnyyyy@hotmail.com]

I have a TD gemini (auto) and i have a manual gearbox and engine for it. what would a machanic charge to put it in for me ?