I'm putting in the new AC Delco LS6 clutch and the literature says the "external factory balance on the engine must be maintained. To do this, remove the existing flywheel and place it beside the new one so that both flywheels are in the same position relative to the crankshaft dowel. Place the new balance weights in the same locations on the engine side of the new flywheel as the old balance weights were placed on the one you removed from the vehicle." First of all, my factory flywheel doesn't have any external balance weights on it. Second, I thought the LS1's were internally balanced. Third, aren't the LS6 clutch assemblies balanced with the flywheel in the box? If so, why aren't there any kind of alignment paint marks. Finally, my engine doesn't have a crankshaft dowel. What do I do? I want this car running today!

 

Aaargh!!! Can't get the $*!&@# transmission to seat against the bellhousing!!! Input shaft won't go through the pilot bearing and I can't figure out why. I used my old input shaft as a clutch alignment tool and I made sure the pilot bearing slipped over the new input shaft. WTF!

 

How are you doing this? Lift? Driveway? You may need to put it on and off a few times to get the input shaft turned right to slip in, also, make sure you line up the dowels on the sides of the transmission where it mounts to the bell. If you're laying under your car its a huge PITA, just keep trying. Took me 4 hours to get mine in and lined up that way. I did it on a lift today and it took literally 5 minutes both ways. As far as the balancing, the pressure plate only fits on one way (the dowels are not symmetrical). It should be neutral balanced. I have the same clutch kit you do and have had no problems with balance/vibrations. That literature is probably something that gets stuck in every box.

 

Make sure you have the bleeder open on the slave, or you can blow out the seal trying to force the trans up onto a hydro-locked TOB..

 

I figured out the part about the clutch only going on one way. No weights on my old flywheel, so I went ahead with the install. The last time I installed my tranny, I got it in without much difficulty. Today, I can't get the friggin input shaft to go through the pilot bearing.

 

Already tried that trick...no worky

 

What I have had to do in the past was get the input shaft into the clutch and the kind of gently wiggle the transmission in circles to get it to find the sweet spot in the pilot bushing to get it to slide in. I don't know what your situation is as far as room to work with or if you have help or whatever.

 

That's what I was thinking.

An input works better than a plastic pilot tool and an input still isn't quite the same as a trans. balanced in mid-air on a jack. Do the above and you'll have it.

 

I can't wiggle any more... I'm too tired. I'll try again tomorrow.

 

I have done this plenty of times oh the garage floor with a buddy. When I get it up there and its giving me a hard time, I just put the drive shaft in the tailshaft and spin it abit while someone pushs. Works everytime, good luck.

 

Didn't work this time!

 

Un-friggin-believable, my luck with this tranny. The input shaft on my new tranny (GM style retro-fit) is way longer than the one on my old one. I removed the front adaptor and compared the input shaft to one from my broken F-body tranny. The splined part of the shaft is hitting the pilot bearing! I can't just swap my old F-body input shaft in either because it has 31 teeth on 4th gear and the new tranny has 29 teeth. So, can I get an input shaft that has 29 teeth on the gear and is the same length as an LS1 F-body input shaft?

Do I need to pound the pilot bearing in further?
Do i need to have the input shaft machined down?
Do I need to use a spacer plate between the bellhousing and front adaptor?

 

I mentioned this when you first started this project (Post #11), never received a response...

https://ls1tech.com/forums/manual-tr...ift-rails.html

Sorry, figured you read my response and did the needed parts swap..

The retro front plate is pretty much a matched set with the input shaft and countershaft.
Best thing would be to sell it and get an LS1 version.

 

Yeah, Mike, you did mention that and I didn't notice. Rats! The adaptor plates are the same thickness between the two transmissions and the difference in shaft shims under the bearings certainly don't account for the 5/8" difference in length between the two shafts. Wished I had noticed that earlier. I got this brand new transmission really cheap, so even with a new input shaft I'm still just a little over 1/2 the price of a new F-body trans. May not be worth the headache though.
BTW, the retro input shaft measures 8 3/8" from the bearing face to the end of the shaft, the F-body one measures 7 3/4"

 

Are you talking about the T5/Muncie adaptor plate on the retro? Or the Front plate of the transmissions? If you changed front plates to an LS1 version, you would have needed almost .100" of shims on the retro counter shaft. You can't put an LS1 countershaft on a retro front plate, because the bearing race hole is about .060" shallower than an LS1 front plate.

The retro input shaft is longer to account for the 1/2" bellhousing adaptor plate and SBC recessed pilot.

 

I used my F-body front adaptor. I did have to shim up the input shaft bearing about .045", the countershaft bearing about .035", and the countershaft extension bearing about .005". Basically, I have an F-body front adaptor (#1A in the Tremec manual), The retro main case (#44), F-body extension housing (#86), and all the retro guts.

Wait a minute. Isn't the GTO tranny identical except for the gear ratios? Won't an '04 GTO transmission bolt right into an F-body? How about I get the input shaft from one of those?

 

GTO is a MN12 and has double cone synchros on the input shaft, totally different than single cone on the LS1.

 

Crud. I bet y'all are having a good laugh at my expense. Oh well, live and learn.

 

Not at all.. Unique projects have unique issues. Feel free to use the forum to "measure twice, cut once.."

 

I found a 2006 GTO transmission for $1400. Isn't the GTO transmission a direct bolt-in? If not, what needs to change, extension housing, clutch/flywheel? If I have to, I'll fix my F-body tranny, but I really want to run the steeper gears. That's why I wanted to make this retro transmission work so much.