What I'm working with!

[Kirden]

If I remember correctly he was having it machined to mat up to an L-series. Should handle a lot more torque than the L-series trannies, and half as old :P

 

Edit:

http://community.ratsun.net/topic/55746-my-blue-240z/page-5

 

It is very picture heavy and honestly I haven't kept up with it recently, but it seems like a great idea. The problem he ran into was finding a machinist to modify the bell housing.

[mrbigtanker]

There's more to this tranny, that went out on you. My first thought is something was wrong and it aint to much horsepower.

[thisismatt]

Ah, tanker, you have a keen eye, my friend.  I do believe you're right, something was wrong, indeed!

[uberkevin]

I agree something was wrong..not sure what.

 

The ka trans to l mod doesn't sound that hard but like you said finding a guy to do the job may be hard.

 

Okay yeah I had slammed it into gear a few times but really I drove it like a new car/motor cuz that's what was... I beat the piss out of my 4 speed behind the l20b.. that thing was mean! And I was way hard on both!!

[datzenmike]

The 71B will handle a 280zx's power/torque.
 
Oh Nooooos! Just got caught up on this thread.

 

 
 

Is my problem the fucked up chewed upness around the shaft?

This isn't right. Earlier 71B 4 speeds has a bushing that supported the mainshaft to keep it centered otherwise it would 'flop around' and that wouldn't help the seal any. The bushing was pounded in and then machined to tolerance to fit the main shaft. Later transmissions and I think all 5 speeds, dropped the bushing and just machined the case to do the same job. None of my info shows a removable bushing in any 5 speed. The fact that it's sticking out the back and chewing the seal says volumes. It shouldn't have this bushing and if it did it's supposed to be pressed in.

 

Pounding one in may have caused it to seize to the mainshaft and spin inside the soft aluminum case. You wouldn't have heard it above the loud exhaust is my guess. With enough play in the case the whole weight of the spinning driveshaft would have just added to the damage. I assume it was vibrating pretty good just before the end.


 
 

Look at the left one. Just above the adapter plate and in the center looks like a crack going up to a damaged area. Could be a casting ridge?


This is not the first to explode. Icehouse had one go on him but a 71C. Tail came apart and shook the front off. Fucked driveshaft and exhaust.

 

 

[flatcat19]

Well, shit.

 

That sucks. Glad you are OK, Kevin.

[uberkevin]

Me and banana pushed the bushing about flush.. but yeah right before it happened there was a horrible vibration the bang! But really it was seconds then bang.

 

When we got the truck to my house we pulled some stuff from under the truck. One part being the bushing we'd pushed in.. it was able to move freely on the yoke still.. but still wow!! I'm glad I'm okay too.. I was backwards on the freeway!! Then what looked like my front end going to hit the rails and back facing the rigjt way again... it could have been really bad!! If it had been rain like the other days... fuck...

[wayno]

Sorry, but I cannot agree with the last sentence in this statement, I haul mass amounts of weight in my work truck all the time, I haul a trailer around almost every time that truck moves, I power shift all the time, I am always dumping the clutch trying to keep the truck/trailer moving, up hills especially, I have never had a transmission destroy itself like that, I wear them out, I destroy the 2nd gear synchro slamming gears, I have been doing this for years, I have a 2 piece driveline, I call driveline.

no, driveline was solid. the tranny decided to fly apart.

 

its in two pieces probably because he was going 65 when the tranny locked, but the rear wheels didn't, so the driveline just twisted and broke in half.

 

LZ23 and powershifting on a Datsun tranny don't mix  :P

[bananahamuck]

But Wayno do you rev up to at least 4500 and drop the clutch to take off?

 

 

The output bushing had no discoloration at all insde or out.. There looked to be no metal transferance between the yolk and bushing (that would hace surely been the case if it had gotten hot enough to seize )  and the bushing slid feely up and down yolk,, after we pulled it out ,, the casing around bushing wasn't in one piece though. It was all there but the cracks were enough to pull bushing out easily with FATs fingers.

 

My theory is that ,,, whatever caused the bushing to back out the first time as those don't jusyt back out for no reason( internal vibration,, wobble from bad bearing ,whatever )  was what eventually caused the extremely sudden gear removal process to happen.. 

 

That and getting 3 gear rubber out front of my house, twice,,, did i mention we have chip-seal out there??

:poke:

 

:rofl:

 

 

 

 

No worries,,  members here in the South Sound aren't always for themselves and we will supply almost anything you need to get that hoooopty back on the street.   Heads up move forward and all the shit.

 

 

Because Datsun

:)

[wayno]

I don't know what RPM I am at when I shift under them circumstances, I just know I am floored, I can only get so much weight up a hill with the setup I have, and I hate crawling up the hill in first, so I floor it and when there is nothing left I slam second, I had a helper with me once, he turned and looked at me like I was crazy when I did it while he was in the truck, and as I said, I ruin the second gear synchros eventually from slamming them, as I get it in gear and dump the clutch as fast as I can.

I did lock up a dogleg once, but it didn't explode.

Now I am not saying that it is not the tranny that exploded, but I call the driveline because it is more likely that it is what let go, there is just to much stuff under there that points to that conclusion.

At first I thought that maybe it had something to do with the yoke, and how far it might have been sticking out of the tail of the transmission, slamming gears and axle wrap could possibly have pulled it out far enough to have the yoke wobble and come out while destroying the tailshaft in the process, but he was going from 4th to 5th, so I am not sure if the engine has enough torque, but it certainly might have the HP to make that driveline vibrate and turn into a noodle.

Is the output shaft bent?

It's that one piece driveline I keep pointing to because they didn't make them like that after the 520, although I cannot recall if the 720 short box/regular cab had a 2 piece or not, but I would guess it was 2 piece.

Did the bushing that you guys pushed back in go in easy, or was it a bitch to get it back in there?

But Wayno do you rev up to at least 4500 and drop the clutch to take off?

 

 

The output bushing had no discoloration at all insde or out.. There looked to be no metal transferance between the yolk and bushing (that would hace surely been the case if it had gotten hot enough to seize )  and the bushing slid feely up and down yolk,, after we pulled it out ,, the casing around bushing wasn't in one piece though. It was all there but the cracks were enough to pull bushing out easily with FATs fingers.

 

My theory is that ,,, whatever caused the bushing to back out the first time as those don't jusyt back out for no reason( internal vibration,, wobble from bad bearing ,whatever )  was what eventually caused the extremely sudden gear removal process to happen.. 

 

That and getting 3 gear rubber out front of my house, twice,,, did i mention we have chip-seal out there??

:poke:

 

:rofl:

 

 

 

 

No worries,,  members here in the South Sound aren't always for themselves and we will supply almost anything you need to get that hoooopty back on the street.   Heads up move forward and all the shit.

 

 

Because Datsun

:)

[flatcat19]

So Kevin still drives like an asshole is what you're trying to say?

 

 

Learn something, Kevin?

[uberkevin]

I doubt ..I did anything in the less than 500 miles I put on it.. like I said yes I did do some hot rodding but nothing near as much of what the L20B.. I didn't even get past 75 once... and while I was driving the truck I did drive a lot better than I did down there Flatcat

[DanielC]

My theory. 

The transmission went into two gears at once, or did not come out of a gear before going into another.

The transmission gears, or more specifically, the ring that slides over the syncro rings, and then engages the gear, their movement is controlled by the three rods that shift the transmission.

On a normal transmission, there is the 1st /2nd rod, a 3rd, 4th rod, and a reverse/5th rod, if a five speed.

On  a dogleg, a first/reverse rod,   a 2nd, and 3rd rod, and a 4th and 5th rod.

 

There is a spring loaded ball, that fits into a detent on the rods.  Each rod has three notches, one for each gear, and one for neutral.

There is also two oblong balls between the three rods.  When you shift into first, or second, the oblong ball is moved into the 3-4 shift rod, and prevents it from moving.  But it is possible for the reverse, and fifth (if a five speed) rod to move when the tranmission is in first or second.

 

If is also possible if the detent oblong ball is missing from between the shift rods for the transmission to go into two gears at once.  on some transmissions, when you are assembling it, and tightening nuts on the mainshaft, you put the transmission into two gears to stop it from turning.  This locks the transmission, and you can easily apply enough torque to the nut to tighten it.

[mrbigtanker]

Well Matt my vision is better then 20/10.

 

What I ment to finish saying is was the u joints bad what about the carrier beating if you have a 2 piece still. I've seen guys beat the shit out of them and still no problems.

[uberkevin]

It was a 520 one piece.

Ujoints I had pressed in by a shop. And balanced.

[datzenmike]

My theory. 

The transmission went into two gears at once, or did not come out of a gear before going into another.

The transmission gears, or more specifically, the ring that slides over the syncro rings, and then engages the gear, their movement is controlled by the three rods that shift the transmission.

On a normal transmission, there is the 1st /2nd rod, a 3rd, 4th rod, and a reverse/5th rod, if a five speed.

On  a dogleg, a first/reverse rod,   a 2nd, and 3rd rod, and a 4th and 5th rod.

 

There is a spring loaded ball, that fits into a detent on the rods.  Each rod has three notches, one for each gear, and one for neutral.

There is also two oblong balls between the three rods.  When you shift into first, or second, the oblong ball is moved into the 3-4 shift rod, and prevents it from moving.  But it is possible for the reverse, and fifth (if a five speed) rod to move when the tranmission is in first or second.

 

If is also possible if the detent oblong ball is missing from between the shift rods for the transmission to go into two gears at once.  on some transmissions, when you are assembling it, and tightening nuts on the mainshaft, you put the transmission into two gears to stop it from turning.  This locks the transmission, and you can easily apply enough torque to the nut to tighten it.

 

While I agree that you can place into two gears at once probably three if you select 5th or reverse, it can only be done with the vehicle stopped and engine off.

[bananahamuck]

Wayno: it went easy.   sometimes things just give up.   sometimes.

 

 

 

So UberAlbert still drives like an asshole is what you're trying to say?


Learn something, UberAlbert?

 

 

Yes ,,,

and no ,, i don't believe he did.

 

:rofl:

 

 

On another subject though, you do know we are indoctrinating him ( with techniques perfected by the SS ) into somehow shaming you into getting your aaass to Canby..   Zero hour ,,, turkey day

[uberkevin]

http://home.comcast.net/~zheimsothtn/transmission.htm

[wayno]

Longshaft

http://home.comcast.net/~zheimsothtn/transmission.htm

[uberkevin]

But I figure I need a new driveine anyway.

[flatcat19]

I told him from day 1 to long shaft it once with a late ZX trans. 

 

 

Short bucket seats and a long tail is just sexy. 

[uberkevin]

I've got some trannys to pick from. To buy.

A ka maybe.. the same kind I had short 720, a 78 620 5 speed a Z 5 speed. And some other 5 speeds tdaaj has.

 

The ka would be the best for long term I believe. .

[uberkevin]

May have just been given the long bed 620 in flatcats front yard.

 

I'll keep you all posted..

May need help getting it here is all..

Flatcat if it's mine you mind touching it? Maybe jack it up and see if brakes work okay?? Maybe check out ign wiring??

It looked a mess what I remember.

 

I'm talking to Chris now.. After forever he got back to me.. He said something along the lines of 'if I can use it it's better then it just sitting there, he could care less about moneys'.. Soo I'll keep you informed. .

[flatcat19]

Um...the ignition wiring I told ya'll to replace? The wiring for the key? Or the wiring for the missing dizzy?

 

Take your pick. 

 

 

 

 

 

I've been planning the great 620 giveaway V2.0. 

[uberkevin]