Author |
Message |
6speedIROC
Senior Forum User
Joined: Mon Feb 01, 2010 12:26 pm Posts: 220 Location: Ottawa
|
T56 HELP - hard to shift into 3rd after rebuild
Just rebuild my transmission as part of the conversion from LT1 to LS1. It shifted perfectly before the rebuild and everything was in great shape inside.
The T56 was an LT1 unit, so converted the front plate & input shaft. Used the gearbox.org Stage 2 rebuild parts, so new carbon fiber/kevlar blocker synchronizer rings, Bronze fork pads, billet keys, 3-4 steel shift fork.
I DIDN'T put in new synchro assemblies. Used GM Dex 3 fluid. Brand new SPEC Stage 2+ & billet flywheel. Tilton master (same as Tick), bled the crap out of it.
The issue is that all gears shift well except 3rd. If I ease it in it will go without grinding, but if I try a quick shift it grinds.
Should I proceed with a 500 mile breakin and hope it works in, or is this more serious..like tear it back down?
_________________86 IROC LQ4/T56/3.50 8.8 (next step..TC76) Build thread: http://ls1tech.com/forums/conversions-hybrids/1819001-1986-iroc-turbo-lq4-t56-build-ac.htmlFormerly 95 LT1 [LE2.2]/T56/4.11 9 Bolt..12.6@114MPH
|
Sat Jun 13, 2015 8:32 pm |
|
|
6speedIROC
Senior Forum User
Joined: Mon Feb 01, 2010 12:26 pm Posts: 220 Location: Ottawa
|
Re: T56 HELP - hard to shift into 3rd after rebuild
No thoughts??
I think it may be that I didn't rough up the synchro mating surfaces on the gears when I rebuilt it. The guy at "TheGearBox" said to rough them up with 80grit emery cloth so the new synchros have something to bite on to.
Do you guys do this?
_________________86 IROC LQ4/T56/3.50 8.8 (next step..TC76) Build thread: http://ls1tech.com/forums/conversions-hybrids/1819001-1986-iroc-turbo-lq4-t56-build-ac.htmlFormerly 95 LT1 [LE2.2]/T56/4.11 9 Bolt..12.6@114MPH
|
Sun Jun 21, 2015 12:31 pm |
|
|
Warp10
Senior Forum User
Joined: Sun Aug 05, 2007 9:33 am Posts: 285 Location: Brampton
|
Re: T56 HELP - hard to shift into 3rd after rebuild
I never had to do that. How where the teeth on the synchro 3-4 assembly? They could have been rounded too much. 6speedIROC wrote: No thoughts??
I think it may be that I didn't rough up the synchro mating surfaces on the gears when I rebuilt it. The guy at "TheGearBox" said to rough them up with 80grit emery cloth so the new synchros have something to bite on to.
Do you guys do this?
_________________2000 Silver T/A Firehawk #C012 M611.00 @ 126.16 Mods: Maple Hawk C012 site
|
Mon Jun 22, 2015 1:34 pm |
|
|
6speedIROC
Senior Forum User
Joined: Mon Feb 01, 2010 12:26 pm Posts: 220 Location: Ottawa
|
Re: T56 HELP - hard to shift into 3rd after rebuild
Teeth were in great shape, no rounding..
_________________86 IROC LQ4/T56/3.50 8.8 (next step..TC76) Build thread: http://ls1tech.com/forums/conversions-hybrids/1819001-1986-iroc-turbo-lq4-t56-build-ac.htmlFormerly 95 LT1 [LE2.2]/T56/4.11 9 Bolt..12.6@114MPH
|
Mon Jun 22, 2015 5:23 pm |
|
|
Warp10
Senior Forum User
Joined: Sun Aug 05, 2007 9:33 am Posts: 285 Location: Brampton
|
Re: T56 HELP - hard to shift into 3rd after rebuild
When you down shift from 4th to 3rd. Same grinding problem?
_________________2000 Silver T/A Firehawk #C012 M611.00 @ 126.16 Mods: Maple Hawk C012 site
|
Mon Jun 22, 2015 5:34 pm |
|
|
6speedIROC
Senior Forum User
Joined: Mon Feb 01, 2010 12:26 pm Posts: 220 Location: Ottawa
|
Re: T56 HELP - hard to shift into 3rd after rebuild
Yes, if I hold pressure on the shifter it will go in no issues after a second or two upshift or downshift. If I try and shift fast it grinds as its not synchronized.
I think its like replacing a clutch, you always resurface.. gives something for the new frislction surface to bit onto. This box was super clean inside..nothing actually needed replacing, just did it as it was apart for the conversion. Had maybe 100,000k.s on it.
_________________86 IROC LQ4/T56/3.50 8.8 (next step..TC76) Build thread: http://ls1tech.com/forums/conversions-hybrids/1819001-1986-iroc-turbo-lq4-t56-build-ac.htmlFormerly 95 LT1 [LE2.2]/T56/4.11 9 Bolt..12.6@114MPH
|
Mon Jun 22, 2015 5:50 pm |
|
|
flame
CCFBG Club Member
Joined: Fri Mar 03, 2006 8:52 pm Posts: 1164 Location: Drayton
|
Re: T56 HELP - hard to shift into 3rd after rebuild
With the engine not running is the 3-4 as smooth as the others? I had a 3-4 synchro that wouldn't let me shift into 3 or 4 no matter how hard I tried.
_________________
|
Mon Jun 22, 2015 6:48 pm |
|
|
6speedIROC
Senior Forum User
Joined: Mon Feb 01, 2010 12:26 pm Posts: 220 Location: Ottawa
|
Re: T56 HELP - hard to shift into 3rd after rebuild
3rd does seem a little stiffer than the others when its not running but no issues with the motor running and the car not moving.
Did you replace the whole syncho?
_________________86 IROC LQ4/T56/3.50 8.8 (next step..TC76) Build thread: http://ls1tech.com/forums/conversions-hybrids/1819001-1986-iroc-turbo-lq4-t56-build-ac.htmlFormerly 95 LT1 [LE2.2]/T56/4.11 9 Bolt..12.6@114MPH
|
Mon Jun 22, 2015 10:24 pm |
|
|
flame
CCFBG Club Member
Joined: Fri Mar 03, 2006 8:52 pm Posts: 1164 Location: Drayton
|
Re: T56 HELP - hard to shift into 3rd after rebuild
Yes the whole synchro was replaced
_________________
|
Tue Jun 23, 2015 7:01 am |
|
|
cam
Senior Forum User
Joined: Sun May 13, 2007 10:48 am Posts: 984
|
Re: T56 HELP - hard to shift into 3rd after rebuild
You installed the CF blocker rings yes? If so they take a while to bed in. Mine wasnt "bad" , no grinding, but it sure was notchy for a while. Its still a bit tight when cold but after a hot pass or two? BUTTA!!! I think id run it for a while, so long as your not grinding teeth and theres no noise it wont hurt anything.
_________________ 1987 IROC ww 99 LS1,TR224/112, STG2 heads ported by American Speed, P Gold springs, LS6 intake, SVO 30's, Ported TB, Comp Cromo Push rods, Katech Rod bolts, LS6 oil pump, T56, SW LT's, 8.8 hybrid rear 3.73, 275/40/17 MT ET streets, lots more
12.1 @ 112 mph 1.69 60'
89 R7U 1LE Players Challenge car all stock.
|
Tue Jun 23, 2015 11:35 pm |
|
|
6speedIROC
Senior Forum User
Joined: Mon Feb 01, 2010 12:26 pm Posts: 220 Location: Ottawa
|
Re: T56 HELP - hard to shift into 3rd after rebuild
Pulled the trans last night. Welded a steel plate to my floor jack and used 2pc 3/8" rods to secure it to the front ears of the trans to stabilize it. Rolled the jack backwards, no manual lifting this beast from the garage floor.. I should have done this 10yrs ago!
Wanted to check the gap from the slave as well. It's right at the high end of the window of .175 to .250" with the .115" shim installed. I called SPEC as I have a 2+ in there and they said the optimum gap is .200 so I may shim it to be 100% sure I have all the travel possible. I'm also running a Tilton (Tick) type master.
On a good note, I was able to pull the trans without disconnecting the slave lines.
I think I'll still pull it apart to re-inspect 3rd and likely roughen up the gear synchro taper faces.
_________________86 IROC LQ4/T56/3.50 8.8 (next step..TC76) Build thread: http://ls1tech.com/forums/conversions-hybrids/1819001-1986-iroc-turbo-lq4-t56-build-ac.htmlFormerly 95 LT1 [LE2.2]/T56/4.11 9 Bolt..12.6@114MPH
|
Wed Jun 24, 2015 9:06 am |
|
|
cam
Senior Forum User
Joined: Sun May 13, 2007 10:48 am Posts: 984
|
Re: T56 HELP - hard to shift into 3rd after rebuild
Check end play as well and imo a 3-4 billet shift fork is essential
_________________ 1987 IROC ww 99 LS1,TR224/112, STG2 heads ported by American Speed, P Gold springs, LS6 intake, SVO 30's, Ported TB, Comp Cromo Push rods, Katech Rod bolts, LS6 oil pump, T56, SW LT's, 8.8 hybrid rear 3.73, 275/40/17 MT ET streets, lots more
12.1 @ 112 mph 1.69 60'
89 R7U 1LE Players Challenge car all stock.
|
Wed Jun 24, 2015 11:34 am |
|
|
6speedIROC
Senior Forum User
Joined: Mon Feb 01, 2010 12:26 pm Posts: 220 Location: Ottawa
|
Re: T56 HELP - hard to shift into 3rd after rebuild
Tore it apart..third gear blocker ring is cracked! 3/4 synchro also doesn't slide so easy anymore. Likely a result of the blocker and a few bad shifts.
_________________86 IROC LQ4/T56/3.50 8.8 (next step..TC76) Build thread: http://ls1tech.com/forums/conversions-hybrids/1819001-1986-iroc-turbo-lq4-t56-build-ac.htmlFormerly 95 LT1 [LE2.2]/T56/4.11 9 Bolt..12.6@114MPH
|
Fri Jul 03, 2015 10:32 am |
|
|
cam
Senior Forum User
Joined: Sun May 13, 2007 10:48 am Posts: 984
|
Re: T56 HELP - hard to shift into 3rd after rebuild
Oddly enough mine let go the other day too. Not sure what all is involved yet, but it aint happy, AT ALL, just a pile of crunchy no movement total failiure My very first 8.8 is surviving through many other part failures though
_________________ 1987 IROC ww 99 LS1,TR224/112, STG2 heads ported by American Speed, P Gold springs, LS6 intake, SVO 30's, Ported TB, Comp Cromo Push rods, Katech Rod bolts, LS6 oil pump, T56, SW LT's, 8.8 hybrid rear 3.73, 275/40/17 MT ET streets, lots more
12.1 @ 112 mph 1.69 60'
89 R7U 1LE Players Challenge car all stock.
|
Fri Jul 03, 2015 1:26 pm |
|
|
6speedIROC
Senior Forum User
Joined: Mon Feb 01, 2010 12:26 pm Posts: 220 Location: Ottawa
|
Re: T56 HELP - hard to shift into 3rd after rebuild
Call Liberty Gears for parts..they seem to be the cheapest.
_________________86 IROC LQ4/T56/3.50 8.8 (next step..TC76) Build thread: http://ls1tech.com/forums/conversions-hybrids/1819001-1986-iroc-turbo-lq4-t56-build-ac.htmlFormerly 95 LT1 [LE2.2]/T56/4.11 9 Bolt..12.6@114MPH
|
Fri Jul 03, 2015 3:17 pm |
|
|
|