Hey guys, 3 weeks ago my TOB decided to grenade driving through a parking lot. Every single piece of it came apart like so:





I ordered an LT4 throw out bearing based on some forum recommendations, I decided to try one from these guys:

https://www.ebay.com/itm/111366445988?ul_noapp=true

I brought it to a welding place and got the collar tacked up where the failure usually occurs, right after I took my flywheel to a clutch shop to get resurfaced. The guy there was very familiar with LT1/ LT4 hot rodding and told me I would have issues. He brought out an LT1 TOB and measured it in front of me, he said the bores are different sized and the clutch fork on my LT1 T56 won't fit on the square top TOB. He also said because the bore was .02-.03 bigger on the LT4 TOB that it will make noise and possibly cause issues.

Sure enough I measured both when I got back home and the bore is bigger on the LT4 unit. Also the LT1 TOB has bearings and the LT4 is just a sleeve. Can anyone confirm if I'm going to run into problems using the square top? I have the LT1 unit that came with the replacement clutch kit but would have to wait until Monday to get it welded and the car is torn apart in my driveway.

Please advise, thanks guys.

 

Is there interference with the smaller diameter, or does it slide freely? If there's any kind of drag then don't use it. Also, way too much grease on that one on the left. Fun fact- Factory stock TB's were notorious for making a rattling noise.

 

Oof... This is me like 5 vodkas in saying pretty much what he said... It it fits it ships...

Think I'll throw myself out now... lol.

 

I'm going to check that in a bit. Right now I'm realizing I *may* have gotten the wrong one. That company lists another TOB, the one I received and had welded has these dimensions:

https://www.ebay.com/itm/111366445988?ul_noapp=true

Bore (Inch )1.373

Outer Diameter ( Inch )3.442

Width ( Inch )1.639

Fits:

1993ChevroletCorvette40th Anniversary Edition Convertible 2-Door5.7L 350Cu. In. V8 GAS OHV Naturally Aspirated

1993ChevroletCorvette40th Anniversary Edition Hatchback 2-Door5.7L 350Cu. In. V8 GAS OHV Naturally Aspirated

1993ChevroletCorvetteBase Convertible 2-Door5.7L 350Cu. In. V8 GAS OHV Naturally Aspirated

1993ChevroletCorvetteBase Hatchback 2-Door5.7L 350Cu. In. V8 GAS OHV Naturally Aspirated

1993ChevroletCorvetteZR-1 Hatchback 2-Door5.7L 350Cu. In. V8 GAS DOHC Naturally Aspirated

1992ChevroletCorvetteBase Convertible 2-Door5.7L 350Cu. In. V8 GAS OHV Naturally Aspirated

1992ChevroletCorvetteBase Hatchback 2-Door5.7L 350Cu. In. V8 GAS OHV Naturally Aspirated

1992ChevroletCorvetteZR-1 Hatchback 2-Door5.7L 350Cu. In. V8 GAS DOHC Naturally Aspirated

1991ChevroletCorvetteBase Convertible 2-Door5.7L 350Cu. In. V8 GAS OHV Naturally Aspirated

1991ChevroletCorvetteBase Hatchback 2-Door5.7L 350Cu. In. V8 GAS OHV Naturally Aspirated

1991ChevroletCorvetteZR-1 Hatchback 2-Door5.7L 350Cu. In. V8 GAS DOHC Naturally Aspirated

1990ChevroletCorvetteBase Convertible 2-Door5.7L 350Cu. In. V8 GAS OHV Naturally Aspirated

1990ChevroletCorvetteBase Hatchback 2-Door5.7L 350Cu. In. V8 GAS OHV Naturally Aspirated

1990ChevroletCorvetteZR-1 Hatchback 2-Door5.7L 350Cu. In. V8 GAS DOHC Naturally Aspirated

1989ChevroletCorvetteBase Convertible 2-Door5.7L 350Cu. In. V8 GAS OHV Naturally Aspirated

1989ChevroletCorvetteBase Hatchback 2-Door5.7L 350Cu. In. V8 GAS OHV Naturally Aspirated


The other one they sell is:

https://www.ebay.com/itm/AT-Clutches....c100752.m1982

Bore (Inch )1.323

Outer Diameter ( Inch )3.437

Width ( Inch )1.724

Fits:

ChevroletCorvette1994-1996


Looks like I may have gotten the wrong one? I don't understand though, they made LT1 Vettes before those years. Ugh

 

The .02 larger size difference for the square top one will make no difference. The center of these bearings just "floats" over the input shaft.

I have the square top on my McLeod Street Twin that came with my SPEC 2+ clutch. It fits in the stock LT1 fork just fine. You do need to line up the TO bearing so the flat edge side is parallel with the fork ears to get it on but no big deal doing that

IDK about the ebay application difference but it appears they have a specific part # for the 94-96 Vette one....although the LT4 did not come out till 97....

If the one you have slides over the input shaft easily and your fork engages it correctly and is the same height as a round one than it should be fine

 

According to my research, 93 and prior year Vettes used a ZF 6 speed gearbox. Since not only is the bore size off, but this TOB doesn't have the inner plastic/ composite sleeve I'm not going to risk having issues and tearing all this apart.

On Monday I'll take the LT1 TOB that came with the LUK clutch kit to get welded and hope for the best. If it blows apart I'll try the correct LT4 TOB as a replacement, unfortunate that I made this mistake but hopefully this helps out any future poor S.O.B. that has to deal with this

Edit: If anyone has a need for the TOB I have and got professionally welded, shoot me a PM.