T56 grinding all gears

[hokeplaya05]

so had to get my car towed home over the weekend. was out driving Saturday and all of a sudden the trans started grinding when trying to go into any gear. managed to park it and could not get it into any gears at idle. it wouldn't make any noise dead center in neutral but as soon as I moved the gear shifter either right or left to try to put it into gear it would start grinding and would not go into gear and just grind. I tried shutting it off and putting it into first then starting it and in made a terrible grinding noise so I shut it off. I have the front and rear casing off the trans now and I don't see anything out of the normal, granted I've never opened a t56 before but I don't see any messed up gears or anything. fluid came out out nice and red (had dexIII in it) and it was full. thought the clutch fork had loosened up again (happened last fall) but that was tight. clutch still felt and looks good, no obvious fluid loss or anything. I am thinking the trans needs a rebuild, chassis has 174k on it and I am assuming it is the original trans. anyone have any ideas or what to look at in the trans while I have the casings off it? I have been having issues getting it in reverse the past few months and sometimes first at stop lights so that leads me to believe it needs a rebuild. just trying to narrow the possible issue down before dropping the coin on getting it rebuilt (and probably upgraded while I'm at it). TIA

[95 blackbird]

What clutch do you have?

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[hokeplaya05]

It's a MCleod twin disk I installed last summer, probably around 3k miles on it with no issues till now. Should probably update my sig lol

[95 blackbird]

Did you check your adjustable master cylinder?
I had a similar problem a couple years back and that was my issue. The jamb nut came loose and the clutch went out of adjustment.
Did you notice if all 3 of your pedals were all at the same height?
My clutch pedal was about 2 inches lower than the other 2.

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[hokeplaya05]

yup, it was still tight, I've have it set about an inch below my brake pedal since I put the clutch and master

[95 blackbird]

Ok, I was told all pedals should be even

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[hokeplaya05]

hmm yeah I've had it like that since putting the twin disk in and even before that with a tick master and the previous ebay clutch that was in it and never had an issue

[Injuneer]

T56 service manual, courtesy of Shoebox. There is a skimpy troubleshooting section up front, with possible causes of clashing gears, both internal and external.

http://shbox.com/1/4th_gen_tech2.html#t56

[hokeplaya05]

cool thanks for that! this is baffling me, the more I take it apart the more I find nothing is wrong. throw-out bearing is a little wobbly but I think that is from removing the trans which was a PITA so I will get a new one to be safe. pilot bushing looks good, clutch looks good and is operational, hydraulic systems is still holding fluid and working properly. I'm wondering what could've gone bad in the trans that would keep it from going into all gears, it would be one thing if it were just one or two gears, then I would guess syncros or something but the fact it is all gears has me stumped. the only other thing I can think of is possibly the slave is bad? but I would think I would see leaking fluid if that went bad, no? guess I'll be calling around to local trans shops to see if anyone has experience re-building t56's before shipping it out to a place like RPM or Tick performance for a rebuild/upgrade. I hate seeing this car sit on jack stands in my garage as I have been pretty much daily driving it since April so I'd like to get it back up and running asap

[Injuneer]

One of the things that caught my eye in the service manual was “pilot bearing between input shaft and output shaft binding”. That would probably affect all gears.

[SSlowBoat]

when my McLeod master/slave assembly went bad, it did exactly this. It also started overextending the slave and making the fork grind the pp so bad I couldnt push clutch all the way down

I went back to stock valeo hydros and have had no issues since

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[hokeplaya05]

One of the things that caught my eye in the service manual was “pilot bearing between input shaft and output shaft binding”. That would probably affect all gears.

I'm gonna pull that manual up on my computer when I get home and go through the trans as best I can and take a look at that, didn't notice it just skimming through


when my McLeod master/slave assembly went bad, it did exactly this. It also started overextending the slave and making the fork grind the pp so bad I couldnt push clutch all the way down

I went back to stock valeo hydros and have had no issues since

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hmm okay, and no fluid loss when the slave goes? it is a stock slave with McLeod master and I was looking for fluids when it first happened but the ground was dry underneath so ruled that out. I don't remember if I've replaced the slave since I've had the car so that very well could be it

[SSlowBoat]

I'm gonna pull that manual up on my computer when I get home and go through the trans as best I can and take a look at that, didn't notice it just skimming through



hmm okay, and no fluid loss when the slave goes? it is a stock slave with McLeod master and I was looking for fluids when it first happened but the ground was dry underneath so ruled that out. I don't remember if I've replaced the slave since I've had the car so that very well could be itno, no fluid loss, it overextended. the master uses a stock style slave. the stock style slave "self adjusts" for clutch wear. but if it gets too much pressure from the master it can overshoot.

fyi new stock hydros, new clutch. pedal sits 1" lower than brake pedal

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[Brandon++S]

I had my slave go bad. No fluid loss whatsoever. I believe if the seal is bad inside it will bypass and not engage.

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[hokeplaya05]

okay that's good to know, I assumed it would leak fluid if it went bad. hopefully I didn't pull the trans for nothing :cry: is there any way to tell if the slave is bad other then the symptoms I am seeing? anything I can look for?

still probably going to have the trans rebuilt/upgraded while I have it out, we'll see what some local shops say about pricing/experience

[hokeplaya05]

so took a break from this thing, got burned out and focused on house things for a couple weeks. now I'm motivated and want to get this thing figured out and back together. new slave came today so i decided to get under the car and look things over before i tired putting the trans back in and noticed a dowel pin sitting in the bottom of the bell housing (left it attached to the motor when i pulled the trans). saw that one of the 3 dowel pins was missing from the pressure plate (see pic below), not sure exactly what the dowel pin does, anybody have insight? not sure how i missed it before, but i would assume this couldn't have caused the issues i was having, would it?
38662

[Fastbird]

Is that scraping around the pressure plate from the dowel pin? I ask because when I put a Street Twin into Call911's car, there was interference with the clutch arm and pressure plate. If the arm was being overextended, that would certainly be your grinding noise. I can't see that dowel causing all that unless it was wedged somewhere tight.

[SSlowBoat]

that looks exactly like my pressure plate when my slave over extended dude.

[hokeplaya05]

yes, the scraping is from last year when the clutch fork bolt backed out and was contacting the pressure plate, so it is unrelated to the current issue. sorry, I knew someone was gonna mention that and should've put a disclaimer lol bolt was loctited and torqued properly and was tight when I pulled the trans this time so ruled that out.

I didn't think that dowel pin could cause the issues I was having, thinking I am just going to reinstall it and move on. I will need to open it up a bit as it just slides in the hole easily right now with no resistance.

[hokeplaya05]

well think i figured out the issue :banghead: guess i didn't look at the clutch good enough, going to email mcleod to see what they say. i have no idea how this happens, other disk looks fine and the input shaft spine on the trans looks good too
38663

[80elkyLT1T56]

Is that actually off center from the mounting holes? That would do it.


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[hokeplaya05]

so sent the clutch/flywheel assembly back to McLeod for inspection/possible rebuild a couple weeks ago. they rebuilt clutch and they are now on their way back to me and should be delivered next Tuesday. kicker is they rebuilt it for free (according to the invoice a $500 rebuild) which I was not expecting so shoutout to McLeod for the awesome customer service! I wasn't sure since I purchased the clutch 2 years ago and didn't get around to installing it until last summer so it was out of their warranty period when it failed, but it also didn't have very many miles on it either. I will throw the new slave in for piece of mind when I get the clutch back and hopefully have the car back on the road by next weekend. its been way too long since I've driven it and I am itching to drive it again. will post updated when I get the clutch in and its drivable again

[hokeplaya05]

clutch arrived yesterday, going to get it installed tonight and hopefully have the car back on the road in the next couple days :driving:
38708

[80elkyLT1T56]

Are you using a reverse lock out solenoid?


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[hokeplaya05]

yes, comes on the t56 from factory

[80elkyLT1T56]

How much clearance did you need to cut out from your transmission tunnel? Overall and for the solenoid.


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[Injuneer]

The factory T56 setup includes the reverse lockout solenoid, and fits the tunnel of a 4th Gen F-Body with no interference at all. I also had a 94 M6 (assuming we're discussing the 94 Z28 M6 in his signature) and the car was designed for it.

[80elkyLT1T56]

Cool. My 80 Elcamino wasn’t designed for it and it’s a different beast set up wise. Thanks for info.


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[80elkyLT1T56]

https://uploads.tapatalk-cdn.com/20180927/1c8b57ca7451c34aedd613dbfa664746.jpg


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[80elkyLT1T56]

https://uploads.tapatalk-cdn.com/20180927/076bc74a7ec558cc00819c8af8f35913.jpg


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[hokeplaya05]

cool swap, but yeah my car came with the t56 so the trans tunnel has the room for it, but not much else lol

[hokeplaya05]

put 70 miles on the car today with the new clutch, feels really good and i'm super happy to have it back on the road after 2 months on jack stands

[96LT1355Z28]

put 70 miles on the car today with the new clutch, feels really good and i'm super happy to have it back on the road after 2 months on jack stands

Good to hear and I'm glad McLeod took care of you!

[hokeplaya05]

Good to hear and I'm glad McLeod took care of you!

me too! and with a relatively quick turn around time too. over 200 miles on the clutch now, driving the car any time I can to make up for lost time lol