chawin

Hey guys,

I have a 2000 WS6 with a 6 speed (T56).
One day driving the car Just driving it like an old man in his station wagon. I Went to shift for 6th and had a little grind... Odd cause its always shifted flawlessly. Next time I go for 6th gear get a small grind then it would go in and would pop out if I let off the gas.... Started getting bad fast and would have to hold it in 6th. Now when I go for 6th it wont even grind... Im just shifting into an empty gate... nothing there at all. Now 5th gear is there and goes in flawlessly from 4th but when on the gas its all good... but when you let off the gas the stick moves forward about an inch and a half and sometimes will pop out of 5th and when you get back on the gas the stick moves back that inch and a half. I stuck my hand through the shifter boot hole and put my hand on the tranny and the tranny doesnt move at all (I have poly motor mounts) All the movement is in the stick and internally. 1-4 and reverse are flawless but 5 and 6 are shot and 5 has its days numbered.

My question is what is going on here? I understand that 5th and 6th are on the same main shaft but what is moving in there to cause that much movement under load or no load. Is the gear pack on the main shaft moving? Is the main shaft moving?

I had read somewhere that 5th/6th can be replace/repaired without pulling everything apart? Truth? Or if since someone would already be in there (either myself or a transmission tech) would it be worthwhile to do any modifications that are a known common failure? I guess my biggest deal right now is what does it sound like is going on with my 5th and 6th? If you need more info let me know

jmd

iTrader: (4)

https://ls1tech.com/forums/16471799-post3.html

chawin

Thank you for the reply.

Very odd how it just very randomly happened. Wasnt hot rodding it or fast shifting or anything. Just gingerly driving along. I could see if I was slamming gears but I wasnt.

So to you guys this sounds more like a shift fork issue rather than the actual gears themselves. Although the synchros may have been damaged but beyond that not so much the gears sliding up and down the mainshaft? (my understanding is they are pressed on and may become "unpressed")

Just weird how the shift lever has so much movement depending on how much load is added to the driveline. I just dont understand what else is moving in there if the gears themselves arent moving.

1999Firehawkls7

iTrader: (3)

Take a T56 apart once or look at pics....theres alot going on in there lol

One of the T56 out of a Lt1 we had apart had a broken fork in it, the 5-6 fork is half as thick as the rest.....this is to make room for the extra (6th) gear in the gear box

Half as thick mean half as strong.....thats why ya never bang on 5th or 6th, not saying ya did and thats what caused it neither

BMR Sales2

iTrader: (40)

It could be a number of things. I have seen similar symptoms happen when the splines between the mainshaft and 5th/6th cluster get wore down and build up too much tolerance. The only way you are really going to find out what is going on is to tear the transmission down at least partially.

chawin

Right, I will end up digging into it real soon. Just before that was trying to get a little insight of what could be the cause or what is going on. I have looked at a T56 that was cut in half and played with it for about a half an hour just looking at how everything was working in there. Though this was quite awhile ago now. At any rate the broken fork or broken pads makes sense since the shift lever cant go far enough to fully engage sixth. But then it doesnt make sense that the shift level moves back and forth in fifth gear depending on load put on the engine... That to me would indicate that 5th is moving on the mainshaft when it should not due to the pressed on fit. That to me makes sense right now until I actually tear into it but I could be very wrong. Ive never tore into one so was thinking one of you T56 veterans would have an idea. Thanks for the help and the suggestions so far guys.

chawin

Just a little update if this helps for anyone that would have an idea what is going on. 1-4 shifts fantastic like usual. 5th still goes in flawlessly but depending on the if im giving the tranny load or not it will pop out under no load unless I hold it with a small amount of pressure. The new news is that if I move the leather boot out of the way and put it in 6th and hold the stick and slowly let the clutch out it will go into 6th and stay in 6th... absolutely no movement in the stick no matter if im giving it WOT or not on the throttle at all and it does not pop out. But to get it into 6th you have to pull the stick back so far backward that it interferes with the console like where the ash tray is. We still leaning toward it being the shift fork as educated guesses?

I will be getting it pulled out and torn apart but in the mean time it is interesting to find out what is really going on in there and what you T56 educated guys come up with for explanations. Thanks again!

jmd

iTrader: (4)

Post 2.

Get 'er pulled. :beer:

68BBChevelle

iTrader: (12)

Having same problems what did you come up with?

68BBChevelle

iTrader: (12)

updates ....