ERKEL

I have already put a new LS1 input shaft,midplate and bellhousing. All went together smoothly until I tried to turn over the input shaft with everything bolted up. The input shaft will turn smoothly once I loosen the bolts up and pull the midplate out about 1/8 inch. It is a new bearing on the input shaft with no shims and no shims behind the new race in the midplate. I have done a search on here but no threads on this situation. Im wondering if I need to mill the small lip that that is in the midplate the the race bottoms out up against. Any info?

85MikeTPI

iTrader: (9)

- Blocker ring not aligned/seated into synchro keys correctly
- bearing not pressed on input shaft fully
- incorrect bearing on input shaft
- other incorrect parts for swap

Can you post pictures?

ERKEL

I believe the thickness of the bearing case itself was .785 and the depth from the very outer edge of the bearing to the trans case was .890.

ERKEL

here is a pic showing how i measured the depth of the bearing to the case

jmd

iTrader: (4)

'93 front plates had a shallower recess for the input shaft bearing outer race.

That may or may not apply to early '94 boxes, but that seems like the issue you have at hand.

85MikeTPI

iTrader: (9)

That was on the M28/M29 units, and this swap would be in the opposite direction, putting a deeper recess LS1 front plate on. The MM6 input shaft shouldn't turn freely on one of those units, but anything's possible. If you are putting the MM6 input on the M29 countershaft, it would be pushing the input out to the side and binding that way.

Did the OP say it was a '94 trans, or is it definitely a '93 ?

ERKEL

It is supposedly a 97 model. I'm going to get another bearing today and mic it to see if it is different.

85MikeTPI

iTrader: (9)

Before you do that, check or take a picture of the countershaft gear and trans case.

Check if it has a CAGS (skip-shift) solenoid in the middle of the case. Also measure the thickness (front to rear) of the countershaft gear that meshes with the input shaft. It should be very close to the thickness of the input shaft gear. (you can also compare the LT1 input gear width to the LS1 input gear)

ERKEL

I got a new bearing today just so I could verify I have the right bearing. Yep I do. This is my first t56 and if im not mistaken the cags is the small sensor on the drivers side of the trans under the reverse solenoid. The thickness of the countershaft gear is 1.070. The distance from the cluster gear to the case is .250 deep. The input shaft gear thickness is 1.115. The distance from the case and the main shaft is .675. With the race pushed all the way in the midplate there is .110 between the end of the race and the midplate. There is a small lip in the midplate where the brg race bottoms out. That lip is .805 from the outside of the midplate and is .115 thick. I can put it back together and I cant turn the input shaft over by hand. If I pull it back apart I can see where there is fluid on the race in the end of the input shaft where it has been against the small brg on the end of the main shaft. There is a small piece of the gold alum tag that is taped to the top of it. Here are the numbers on the tag 9236020 D2232 is on the top and 86-006 E 10397 is on the bottom. I can see where the tag has been broken and there are numbers that are missing in front of those,but that is all I have. Thank You Mike for anything that you might be able to help me with.

85MikeTPI

iTrader: (9)

Your countershaft (and thus the internals) are from a 1993 M28 or M29 T56 and totally different gears from the '94-2002 MM6. You won't be able to easily convert it over to LS1 unless you talk to Jason@TDP about having a custom input shaft lengthened..

The MM6 countershaft gear is 1.160 thick.

The CAGS is the second solenoid in the middle of the case on the drivers side, near the center cover plate. The small sensor under the REV-Lockout is the VSS.

The Tag also indicates it was built in 1993, and you can also count the teeth on the countershaft gear and probably find it has 38, instead of the 36 on a MM6 counter.

jmd

iTrader: (4)

The reason you're unable to turn the input is due to a mis-match of gears. The 31 tooth input in an MM6 box meshes with a 36 tooth countershaft gear. The M28 box you have is 29 / 38.

Sorry you ran into this obstacle in your project.

85MikeTPI

iTrader: (9)

Actually the various parts will mesh together, but the diameter of the gears is changed to result in more/less teeth. In this case the 38 tooth countershaft is larger in diameter and binds the 31 tooth MM6 gear out to the side.

ERKEL

The cluster gear does have 38 teeth and the input has 31. Looks like I'm screwed for the time being. I guess I will make a call Monday and see how much this input shaft will cost.I've got a new stock input if anybody needs one. Thanks for all the help guys.

ERKEL

If anyone has a 93 input shaft in good condition I would be interested in buying it. I sold the stock one last year and now I could use it. I might go a different way on this project and use this Trans on another.

jmd

iTrader: (4)

Thanks.

I was thinking gearsets with different spans between the major o.d. would have different tooth face angles.

BIGdave111

I may run into a similar situation, I have a 1995 z28 with the stock lt1 and T56. I tore apart the trans and its not worth fixing (teeth missing from gears, mainshaft splines wiped, etc etc) want to know if I can use a 97-04 corvette T56 and use my Lt1 bellhousing, midplate, tailshaft housing and shift fork assy to convert it for use behind my LT1? PLEASE HELP ME !

jmd

iTrader: (4)

There's no stock input shaft to accomplish that. Sponsor TDP has posted about a trans. w/ some custom work like that for sale however.

LT1BC

I'm new to this and had spent some time reading 85TPIMikes 800-1,000 HP hybrid write up.

One of the versions he listed was using a C5 Donor without an LS F Body core. A F Body front (mid) plate was swapped onto the C5 Donor making this (essentially) an LS F Body T56. I didn't see a parts listing for a LS input shaft though, so not sure if I'm missing something in my understanding.

BIGdave111 mentioned changing the Lt1 mid plate, and the Lt1 bell housing, but he didn't mention changing the main shaft (to the SSR 32 spline, or an F Body 27 spline shaft - do both of these swap over to the C5 gear sets?). Is that what he's missing to convert the C5 into a direct bolt on to the Lt1?