Huge torque converter gap after trans swap

[mwojoaa96]

this is a continuation of a different solved thread.

I am working on a 1995 c1500 4.3
I bought a new 1995 used trans from a 1995 fbody lt1.

I converted the tail shaft, shifter, blah blah blah and went to bolt it up

Now I have a 1/4”+ gap between my torque converter and flex play. I know 1/8 to 3/16 is normal but this is a big gap. What changed!!!

The transmissions looked identical besides the stuff I swapped up. Both K cases, same 298mm input shaft. Even swapped a new TC on and same issue!! I am stumped… what can I do?

 

[mwojoaa96]

Sorry actually measured it the gap is more like 5/16

 

[Orpedcrow]

Flexplate on backwards? I do t know if that’s possible, but it was the first thing I thought of.

 

[Orpedcrow]

Next time you have the transmission out, take a straight edge like a carpenters level and place it across the bellhousimg bolts, then measure from the bottom of the edge to the shaft and or the front of the front pump. Check both transmissions and verify they are the same dimensions.

 

[pressureangle]

this is a continuation of a different solved thread.

I am working on a 1995 c1500 4.3
I bought a new 1995 used trans from a 1995 fbody lt1.

I converted the tail shaft, shifter, blah blah blah and went to bolt it up

Now I have a 1/4”+ gap between my torque converter and flex play. I know 1/8 to 3/16 is normal but this is a big gap. What changed!!!

The transmissions looked identical besides the stuff I swapped up. Both K cases, same 298mm input shaft. Even swapped a new TC on and same issue!! I am stumped… what can I do?

It's probably ok in a stock low HP setup. But here's Circle D's installation recommendations- greater than 3/16" they want shims between the converter and flex plate.

Installation Tips

Our mission is to make exceptional torque converters while providing unparalleled knowledge and outstanding customer service. We are driven to continually improve and raise the bar with our products, relentlessly pursuing perfection. Ford, Mopar, GM, and others are supported: 4L60, 4L80, 6L80...

www.circledspecialties.com

 

[mwojoaa96]

Let me clarify what I mean. So once I have everything installed. I can slide the torque converter flush with the flex plate but the 5/16 exists between the pump and the TC. Is that normal?

Note my engine is the 4.3 vortec.

 

[L31MaxExpress]

Let me clarify what I mean. So once I have everything installed. I can slide the torque converter flush with the flex plate but the 5/16 exists between the pump and the TC. Is that normal?

Note my engine is the 4.3 vortec.

No it is not normal, needs to be shimmed tighter. I would use the recommendations from Circle D. The pump hub is not exactly strong and if too much gap exist, the pump hub drive on the torque converter will not make full contact with the pump hub and bad things can happen aka the pump hub breaks.

 

[95burban]

Put a flat washer between the tc and flex plate

 

[mwojoaa96]

No it is not normal, needs to be shimmed tighter. I would use the recommendations from Circle D. The pump hub is not exactly strong and if too much gap exist, the pump hub drive on the torque converter will not make full contact with the pump hub and bad things can happen aka the pump hub breaks.

Should I shim it until there is zero gap all the way from the pump to the crank? Probably get longer bolts too?

 

[tayto]

the issue with it being 1/4"+ is the pilot might not be engaged in the back of the crank correctly. sounds like converter was manufactured wrong