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My '76 710 Goon


datzenmike

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I have a zx 5 speed but I'm fairly sure it's the first year ('79) and does not have the monster over drive ratio. I'll check it again but I had it in my 620 and didn't notice a big difference when I swapped it in. It also has all the markers that ID it as a pre '80 model. Starting around '80 the shifter was modified and the cross pin hole raised. Raising this is actually raising the fulcrum point which allows a shorter shift without shortening the shift lever. Shortened shifters are useless if you have to in any way reach for 1st, 3rd or 5th. To be proper, you should be able to row through the gears without moving your shoulder and elbow and wrist horizontal.

 

Early 280zx

5speedfor710goon010Large.jpg

 

Later 720 diesel 5 speed.

5speedfor710goon012Large.jpg

 

 

Doesn't look like much but here are two 720 shifters I have. The first one is maybe 1/4" longer below the pin and this translates to over an inch at the shift knob.

 

5speedfor710goon005Large.jpg

 

 

Well the easiest way to get that shifter on is to swap the rear case from the 720 onto the zx 5 speed.

 

280zx

5speedfor710goon007Large.jpg

 

 

720 Same right? Not really, if you look at the speedo pinion you can see that it is secured with a 10mm bolt and key in the 6:00 position but the 280zx is at 12:00 Pre '80 pinions won't work in post 80 trannys. Not sure why they changed this arrangement possibly it was the drive gear on main shaft.

 

5speedfor710goon011Large.jpg

 

280zx

5speedfor710goon026Large.jpg

 

later 720

5speedfor710goon027Large.jpg

 

I found the plastic one 0.025" larger diameter so I swapped it onto the 280zx main shaft. Perfect fit.

 

 

5speedfor710goon013Large.jpg

 

Now the other side of the later tailstock. It has a reverse check sleeve added which the earlier ones don't. Its the bigger holes with the bolt holes on each side. I've heard that it prevents you from shifting into reverse while the vehicle is moving.... sort of like a lock out. I don't think it is from examining it. The shift lever inside pushes against a spring load in the check sleeve. I think that it provides a slight resistance when trying to put into reverse. Maybe this added resistance is noticeable and lets you know you are near reverse??

 

The other hole is on both tailstocks and is the return spring and plunger. Helps center the shifter in the 3/4 position when in the neutral gate

 

 

Looking into the tailstock you can see the shift 'striking rod'

 

280zx

5speedfor710goon017Large.jpg

 

Notice the smaller finger sticking down to the right on the later tranny. This engages the reverse check sleeve that would be in the hole on the right side of the case.

 

5speedfor710goon006Large.jpg

 

The longer 'finger' pointing down to the left slides (up and down) through the neutral shift gate below...

 

5speedfor710goon022Large.jpg

 

 

Top to bottom looking forward on the pass side is the 1st/2nd, 3rd/4th and 5th rev shift rods. The rods move opposite to the shift lever. 1st/3rd/5th rods move to the back of tranny.+-

 

5speedfor710goon021Large.jpg

 

I test fitted the 720 tailstock and found the easiest way to engage the shift rods is to place is 1st and lower the tail onto the rest of the tranny. The manual says to leave in neutral and hold the shifter over to the right but it did not work. Tried it twice my way with excellent results.

 

Tomorrow I'll get some gasket sealer and a new rear seal and we're in business.

 

5speedfor710goon023Large.jpg

 

The rev/5th shift fork is massive wide. (they are usually about 1/3 this size)

 

 

Check the shift fork width on this other 5 speed...

 

transFS5W71Bin5th001.jpg

 

 

The 720 rear mainshaft bearing was extremely loose and the shaft could wobble about 1/8" up and down. The 280zx one here is snug. Hard to believe I found this tranny in a wreck. The car was so stripped and crushed I thought it was a 620. I bought it for $30 and got the flywheel, tranny, alternator and a few other things. Had it for 6-7 years under a tarp, "just in case". Finally one day my 620 5 speed jumped out of 5th and refused to stay in gear. Fine for around town but two weeks later 2nd started doing it also. Swapped it in with some semi synthetic oil and have been across Canada and back a good half dozen times. It was reliable, quiet, and shifted with a satisfying 'click' into each gear. I pulled it again when I switched to the Z24. Now it's going in the 710 goon.

 

 

 

 

 

 

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struts001Large.jpg

 

Hmmmmmmm

 

Looks like the makings of a catapult.... :D

Could use something like that when I clean the yard up in the spring, after the snow melts

Fling some dog turds towards some unsuspecting neighbors......clandestine operation of course.... :lol:

 

On another note.....I wanted to use my shorter 720 shifter(26"trannie) in my 31" long tail trannie. fits, works fine...but the shifter is way too close to the seats/driver.

Had to use the longer shifter that came with the trannie.

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Well finally got around to completing the tailstock swap.The 280zx bolts were longer so had to grab another set.

 

goon5speedswap009Large-1.jpg

 

'80 and on trannys have the speedo pinion 180 around from previous years so the cut for the key is 180 different. Here are two similar pinions one is the 280zx and one the later 720 diesel . I put the key way cuts to the left (bottom above threads) but note at the top that the cog gears are off set in opposite directions and won't properly mesh with the drive worm on the mainshaft.

 

The correct one is on the right.

 

goon5speedswap010Large.jpg

 

Installed

 

goon5speedswap018Large-1.jpg

 

Now the check return spring and plunger. I think it helps the shifter sit in the 3/4 gate area when in neutral.

 

goon5speedswap017Large.jpg

 

goon5speedswap020Large-1.jpg

 

Reverse check sleeve. Unknown what it does

 

goon5speedswap019Large-1.jpg

 

'New' breather from another tranny to replace thew broken one.

 

goon5speedswap021Large.jpg

 

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Had to work today...... but had time to make some measurements. Looks like the 5 speed shifter is going to be only 2.5 inches to the rear of where the 4 speed shifter was sitting up through the floor. I measured back from the engine and confirmed the 4 speed location and took a picture of the hole inside the car.

 

goon5speedswap022Large.jpg

 

The hole in the tunnel is quite long and there is a screw on cover over it. I should be able to remove it and move back 2 1/2 inches and install again. There's a clip thing under the E brake handle and there's one forward that's U shaped for securing the center console. When done it should look stock.

 

 

Here's about where the 5 speed shifter should sit. The hole cover has to move back to place it in the center.

 

goon5speedswap026Large.jpg

 

Sitting in position the shifter is much shorter than the stock monkey motion stick and further back. Height seems good. I have a nice 720 boot that fits and seals over the top of the shift pin/bushing area. I'll make a nice black naugahyde wrapper and draw string for the console and stick.

 

goon5speedswap028Large.jpg

 

I was expecting to have to cut the metal tunnel. Maybe I can get away without having to do this.

 

Next is the mount modifications.

 

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There are two lengths of driveshaft on the goon. The 4 speed tranny is shorter than the automatic tranny so the 4spd driveshaft is longer than the auto driveshaft.

Auto and standard tranny driveshafts.

710driveshaft001Large.jpg

 

The difference in length is almost exactly the difference in 4 and 5 speed tranny length so I plan to use the shorter auto driveshaft with my 280zx 5speed. Now if you are running a C type tranny behing your KA, they are even longer, so an even shorter driveshaft would be needed.

 

Almost for sure your driveshaft was shortened. You could measure it from center of U to U joint and I can measure mine.

 

I'll bet your KA could have been moved back. I hear all the time about people complaining about getting at the tranny mounting bolts to the engine against the fire wall. Mine on the 710 had ample room and I had absolutely no problem slipping a spanner in there with my hands. I'll bet the 710 has more room than the 510.

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No problem INDY.

 

I've asked for measurements for the 240 and the Hardbody C types and never get the same answer. To get the correct length the tranny should be standing up with a straight edge across the output where the d/s spline goes in. Measure vertically up from the bell to the straight edge. Anything else like from the bell to the spline area is actually on a slope and will be longer. I realize this is very difficult when in the car and also some trannys have a dust shield over the end.

 

I think these are Hardbody top and 240 under.

 

transshortD21CtypeKA24EandlongS13KA.jpg

 

 

KA S13 top and CA18ET or CA20E bottom. I wonder if these are slope measurements?

 

S-13andS-12MKIICtypes.jpg

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Well the mount needs to be spaced back about 2.5 inches for the 5 speed. I get all my ideas at work. Was thinking that if the automatic and the 5 speed are similar length, maybe the rear tranny mount and cross member from the auto goon would work on the 5 speed swap. Hell maybe the cross member is just turned 180.

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Long story. First they aren't a clamp, this is where I went wrong when looking for them and all anyone could come up with is a large muffler clamp. They are called a split collar. Just go or contact a large fastener company and they can look them up. Now that I know the name maybe a plumbing store or machine shop supply could get them? They were about $10 each but well worth the price for not having a mufler clamp on my srut. Look cool too. 2 inch inner diameter. They also come with single screw tightener but you have to slide the collar on before everything else. The two screw ones come appart for easy install/removal.

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Big day tomorrow. I'll be lifting the 5 speed up into the 710. Too tired tonight but I did go out and clean and lube the clutch arm and pivot and swapped the 200mm release collar onto it.

 

This is the arm I'm using from a diesel 720. They are all the same on the FS5W71B.

 

trannyforkBtypeLarge.jpg

 

710's F4W63 4 speed arm and the 5 speed below it. Almost identical. Same dimentions but slight bend along the length.

 

goon5speedswapF4W63abdFS5W71B036Large.jpg

 

5 speed arm with the 710 release bearing and sleeve/collar installed, greased and installed ready to go..

 

goon5speedswap200mmcollar037Large.jpg

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PART I

 

Bright and early today I unwrapped the goon and got out my tools. Carried the 5 speed over and rolled it under the car. Used a hydraulic jack to lift it up and with some reasonable troubles got it into the back of the motor and bolted down. (the 4 speed bolts were not long enough, shit like that)

 

PART II

 

Feeling lucky, I slipped the rear cross member in loosely (180 degrees looked right) and then slid the tranny mount onto it.

 

goon5speedswap203Large.jpg

 

It fit more than perfect. I've bolted a few trannys back in that were way more trouble to get the bolts through the holes. So on a 710 4 speed swap the crossmember 180 and use the 710 mount. If there is anything wrong, it's that it may sit slightly high. Perhaps I could remove the mount and just slip a small sheet of rubber between the tranny and the crossmember and bolt down.

 

There is less clearance for the exhaust as the clearance hump in the crossmember is now on the wrong side.

 

Shifter fits and clears, though it may be high.

 

goon5speedswap207Large.jpg

goon5speedswap208Large.jpg

 

The shifter has a bend in it so I have the option of closer or further away. I tried both and will stick with closer to the driver for now. The further away position I could shift 1st to 2nd and still grip the steering wheel.

 

This is 1st with the shifter closest to the driver...

goon5speedswap210Large.jpg

 

2nd..

goon5speedswap211Large.jpg

 

Seriously short throw. I also discovered what the reverse check sleeve does. (I thought I fucked up the tailshaft swap) I was testing the gear positions and tried to put it in reverse and it wouldn't... wtf??? Found that you cannot shift directly into reverse from the 5th gear position. You can from any other gear. This would prevent a grinding miss shift into reverse when downshifting from 5th into 4th. Neat!!!

 

PART III

 

Using the shorter 710 automatic driveshaft from my parts car proved to be a good idea. Fits, nothing more need be said about it.

 

goon5speedswap201Large2.jpg

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Seriously short throw. I also discovered what the reverse check sleeve does. (I thought I fucked up the tailshaft swap) I was testing the gear positions and tried to put it in reverse and it wouldn't... wtf??? Found that you cannot shift directly into reverse from the 5th gear position. You can from any other gear. This would prevent a grinding miss shift into reverse when downshifting from 5th into 4th. Neat!!!

 

Good to know.....I think.... :)

Just checked 1 of my trucks....yup....won't go into reverse from 5th.....good.

Checked my other truck, with the recently installed 1980 720 2WD trannie....nope....goes directly into reverse from 5th.....bad.

Hmmmmmmmmm....maybe some issues....stuck....?

Shall yank 1 out on another trannie and have a look.

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Never tried this before.

 

 

 

 

First thought was porn and or some sorted activity... ;)..... :lol:

Excellent...now just need some 'tunes' to enhance the experience of the viewing 'public'... :D

 

Anywho.....no reverse check sleeve on the 80. Have it on all the others I have...81+

Guess some grinding will give a heads up when shifting from 5th to reverse.... :o

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I've since noticed that there are two sets of mounting bolt holes in the body. There is a second set that allows the mount to be moved back for the longer automatic and should work for the long 5 speed. This way I do not have to 180 te mount. In addition I am going to fabricate something to lower the rear tail about 2-3" to be closer to the stock 4 speed. Stay tuned.

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