quick66

Hi,

First post here...

I'm in the process of rebuilding the G-force T56 out of my '66 Chevelle. I should have taken better notes/pictures during disassembly. I'm having a hard time remembering which spacers/thrust washers go where. I was wondering if anyone might be able to provide some visual identification and/or measurements (ID, thickness, etc...) for the following.

From the TTC T56 Service Manual:

308 #38 & #26 - My tranny has G-force gears with triple cone synchros 1-4. Are these spacers needed? I didn't take anything out of the transmission that resembles these.
3-8 #179 - Spacer that goes between needle bearing and 3rd gear
3-11 -#115 Spacer that goees between the 5/6 synchro and the 6th gear blocker ring
3-11 #108 washer, Thrust
3-19 #135 & 139 Washer, Reverse idler thrust

I feel like an idiot for not taking better notes. I'm normally very meticulous with this type of thing. I was so consumed with trying to look for signs of damage that I didn't pay close enough attention to the parts ordering as I took it apart.

Thanks very much for any help you can offer.

85MikeTPI

iTrader: (9)

http://www.eecis.udel.edu/~davis/z28...SR_2pc_Hybrid/

http://www.eecis.udel.edu/~davis/z28...100201_LS7T56/

Any any of the "GTO" builds pictured in:
http://www.eecis.udel.edu/~davis/z28/2008
http://www.eecis.udel.edu/~davis/z28/2009
http://www.eecis.udel.edu/~davis/z28/2010

may help you out with the triple/double cone builds..

The #38 & #26 connect the mainshaft to the double-cone synchros. They are not present in the triples.

#179 ??? You mean #171? That's not used in the triple/double units.

The #115 spacer is a thin metal ring that protects the needle bearing from getting chewed up on the snapring.. It should still be needed/present.

#108 is not used in the 5-6 double cone setups.. The 6th gears have extended flanges in this setup that don't require the spacer.

The Rev idler spacers come in twos, single, and sometimes none at all.. If you don't have any, it may not be a problem..

quick66

Hey Mike,

Thanks for the reply and the links. I misinformed you about what I was dealing with. I thought my transmission had triple cone synchros 1-4. I think only 1-2 are triples and 3-4 are double. I snapped a few pictures of the parts. I'm hoping that you can provide me with some guidance based on look at the pictures. There are two attachments. One is a picture of all (or most all) of the parts. The second one is a picture of the washers. The washers on the right hand row are the ones I took out of the transmission. The ones on the left are what G-Force sent me for the rebuild.

quick66

Durn, the images were reduced a lot during upload. I can email the orginals (high resolution) to you if you like.

Thanks again for your help.

85MikeTPI

iTrader: (9)

I assumed so, since that's what the late model OEMs are..

I'll PM you my email address (although it's not hard to find if anyone was looking for me...)

mike

quick66

I sent you some high res pics Mike. I *assume* that the term "cone" refers to the number of friction surfaces. This is the first manual tranny I have ever tried to rebuild. I've done a serveral autos (TH-400s/350s). This is all new for me

LS123

iTrader: (11)

Here are the parts in order (left pic):

On the left:

-spacer goes on top of the 6th gear needle bearing (against the snap ring)

-next 2 are the spacers below and top of the rear carrier bearing for the main shaft (there are thin snap rings that hold them in place)

-spacer that sit on top the reverse gear and below the snap ring

On the right:

-wave washer between the reverse blocker and the reverse gear

-plastic washer sits on the back side of the reverse synchro

-spacer that sits between counter shaft and the extension shaft (make sure the open end faces forward of the trans)

85MikeTPI

iTrader: (9)

I think you're correct about the 6th gear needle bearing spacer. I mistook it for a 2nd gear spacer, but now that you mention it, it's way too small..

The hi-res pics helped, but I'm still not sure on the top right washer. Definitely not the wave.. I think it might be a custom G-force piece that goes between the counter and extension, like the cup washer, but thick&flat to accommodate the different interface.

Finally, the bottom right washer is the 3rd gear spacer that's on the double-cone units. Too large and not cupped to be the counter/ext spacer.

quick66

Thanks for all the answers and help Mike and LS123. I think I can now put this thing back together with confidence

Any tips on how to fabricate a tool to check the endplay? I've got a good hydraulic mag base and a .0005" indicator that I use for my engine builds. I saw a post somewhere that showed where a guy used some metric threaded rod and a coupler. I'll have to see if I can dig that up again. I just hate to buy a specialty tool that I might never need again. I already dropped $100+ on a long two jaw puller to get the thing apart.

85MikeTPI

iTrader: (9)

I just use a piece of allthread I got from NAPA

http://www.eecis.udel.edu/~davis/z28...CP_%20067.html

If you can't find the M12x1.75 allthread, you can get the same result with SAE allthread and welding a cut-off M12x1.75 bolt to the end. You'll need some nuts and sleeves to lock the allthread to the countershaft when checking it.

quick66

Excellent! Thanks again. I will get back on this next weekend. Hopefully I can get it back together. I only had 120 miles on the transmission when I broke it Went to pull 4th gear at about 7,200RPM and managed to put it in second. The gears stacked up on the mainshaft and 6th gear tried to weld itself to the 5-6 synchro hub. I was able to drive the car home, but it was whining like a three year old in every gear. I bought a new 6th gear, 5-6 synchro hub and all new bearings and races from G-Force. I also had the gears REM coated. I probably didn't need to change the bearings with that few of miles on it, but I figured better safe than sorry. What kind of clearances are you guys running for the main and counter shafts? This trans is behind a 750hp/700ft lbs 540ci big block in my Chevelle. I'm worried that the gears stacked up on a missed shift. I was thinking of putting a little more clearance in it for good measure (maybe .0002"-.0003"). What do you think? I'm running a 10" slipper clutch with sintered iron disk from Advanced Clutches (Rob Youngblood). http://www.advancedclutches.com/metalcoverclutches.htm

85MikeTPI

iTrader: (9)

"stacked up" as in they were binding and burning against the synchro hubs? I don't think that has as much to do with bearing clearances as with the shifter. You may want to use the shifter stops to limit travel, even though the stock T56 has built in stops. The G-force gears may have a slightly different setup than the OEM..

But as for clearances, I usually shoot for:

mainshaft: 0.000-0.002 preload
countershaft: 0.002-0.004 preload
extension: 0.000-0.001 end-play

With new bearings I allow an additional 0.001-0.002 of preload.

quick66

Yes, Mike. 6th gear was burning against the synchro hub. Interesting on the shift stops. I set the stops before I installed the tranny in the car. I'll check it closer this time around. As for the end play... Since I'm using new bearings, are you saying I should add .001"-.002" to the figures above?

85MikeTPI

iTrader: (9)

Yes, add an additional 1 to 2 thousands to the pre-loads, and adding a bit of pre-load to the extension...

Was your failure after 120miles beyond the 500mile breakin period, or 120 miles after you installed it? I wouldn't start thrashing the trans until you give it at least 500 miles, unless its a pure track car. The gears out back (5th, 6th, Rev) are known to burn from lack of lubrication until the breakin period..

I know you probably don't care, but most people here on ls1tech get greated with this thread as their first search experience with G-force T56s:

https://ls1tech.com/forums/manual-tr...ion-parts.html

quick66

Wow, not a very encouraging read there. In all fairness to G-force, I didn't put 500 miles on the tranny. I took it out and started running the heck out of it, and it wasn't their gear that had a problem it was the OEM one. I'll put everything back together and baby it for a while. It's just a weekend warrior anyway. Hopefully it will hold up this time.

quick66

Any tips on how to remove the race from 4th gear/input shaft?

LS123

iTrader: (11)

You need a special removal tool (this is a must) with a slide hammer to get that out.

85MikeTPI

iTrader: (9)

I've used a tool similar to this from harbor freight. OTC makes them also..

OTC-6542

If you don't need to remove them frequently and the races are not heated into the input, the simple hand tool will usually work.

quick66

OK, thanks. I ordered the OTC bearing cup puller and slide hammer. I had a slide hammer already but the thread size/pitch was different. I got all the gears installed on the mainshaft and countershaft extension last night. Everything went together fine using the information you guys provided for the washers/spacers. One other question I have is regarding thrust washer (108) that goes on 6th gear. I have two washers that are identical in width and ID. These washers were in the bottom left and upper right of the picture I attached. One (top right) has some grooves machined in it on one side. The one with the grooves machined in it is what came out of the transmission; the other one came with the snap rings/and spacers that G-force sent me for the rebuild. I would prefer to use the one that came out of there. I'm assuming those grooves are there for a reason. Should the grooves face 6th gear or the counter shaft?

quick66

FYI, I called G-Force and they said I should use the thrust washer that has the grooves machined in it. They said the washer is grooved in order to provide improved oiling of the coupler (e.g. countershaft). The grooved side of the washer goes towards the countershaft. Thanks again for all the help guys!