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4L80E to SM465 swap

Yeah the lock up items for the ECU needs disabled

Mentioning the lengths. We were measuring transmissions with doublers the other day. The TH400 and SM465s measured the same lengths bell housing to output.

I don’t know the 4L80e length, but if it is the same as a 400, the shafts should also be ok
 
Bent77 said:
Yeah the lock up items for the ECU needs disabled

Mentioning the lengths. We were measuring transmissions with doublers the other day. The TH400 and SM465s measured the same lengths bell housing to output.

I don’t know the 4L80e length, but if it is the same as a 400, the shafts should also be ok
Click to expand...
After 85 all gm configurations have the same length driveshafts for the same truck.
All fronts are same regardless rears change based on what truck
 
imiceman44 said:
After 85 all gm configurations have the same length driveshafts for the same truck.
All fronts are same regardless rears change based on what truck
Click to expand...
Sweet. So, since the combination of parts I have is what could have come on my truck from the factory it “should” work.
 
I've decided to do the same with mine a while back. Can't afford an auto, sm465's are bullet proof. And I can piece it together. Any used tranny $139 + core at one nearby pick & pull.
 
Big Ray said:
I've decided to do the same with mine a while back. Can't afford an auto, sm465's are bullet proof. And I can piece it together. Any used tranny $139 + core at one nearby pick & pull.
Click to expand...
Unfortunately you're too far away.
I have 3 sm465 32 spline transmissions with adapters for 205, and one for 208/241
 
Big Ray said:
I've decided to do the same with mine a while back. Can't afford an auto, sm465's are bullet proof. And I can piece it together. Any used tranny $139 + core at one nearby pick & pull.
Click to expand...
I spent too much getting my 4L80E rebuilt about 3.5 years ago and it cracked to pieces. I didn’t even get 10k miles on it. The fluid still looked new.
 
JdubBurb said:
It cracked along the top of the bellhousing near the mounting flange and broke off. The metal seems pretty fatigued now. Some say you can weld it, but I wouldn’t trust it.
Click to expand...

I was going to suggest a product called "Ultra Bell" that's used in the drag racing world, it replaces the bellhousing part of the case. You cut the old bell off and this new bell attaches to the pump bolts. I googled around some and it looks like the 4l80e uses an adapter and th400 bell so it's do-able but gets expensive. If you really wanted to save the 4l80e you can but probably not for the price you can swap to a 465.
 
nvrenuf said:
I was going to suggest a product called "Ultra Bell" that's used in the drag racing world, it replaces the bellhousing part of the case. You cut the old bell off and this new bell attaches to the pump bolts. I googled around some and it looks like the 4l80e uses an adapter and th400 bell so it's do-able but gets expensive. If you really wanted to save the 4l80e you can but probably not for the price you can swap to a 465.
Click to expand...
I’ve seen that, but I think the 4L80 setup is a bit more involved than it is on other transmissions. You’re right, it’s definitely more than swapping to an SM465.
 
nvrenuf said:
I was going to suggest a product called "Ultra Bell" that's used in the drag racing world, it replaces the bellhousing part of the case. You cut the old bell off and this new bell attaches to the pump bolts. I googled around some and it looks like the 4l80e uses an adapter and th400 bell so it's do-able but gets expensive. If you really wanted to save the 4l80e you can but probably not for the price you can swap to a 465.
Click to expand...
I got one of those bells I wanted to change an AMC th400 to a GM bell.
But then I found out I need a small torque converter which for racing is normal but for normal stall speed it's a custom job and expensive.
Cost me $250 + shipping for it too :doah:
 
Bent77 said:
Yeah the lock up items for the ECU needs disabled

Mentioning the lengths. We were measuring transmissions with doublers the other day. The TH400 and SM465s measured the same lengths bell housing to output.

I don’t know the 4L80e length, but if it is the same as a 400, the shafts should also be ok
Click to expand...
The ecu knows if what gear the automatic is in and control lockup of the torque converter, correct?
I can move the brake safety switch to the clutch pedal?
If I’m using my existing steering column what would I need to alter(it’s a column shift now, of course)?
 
JdubBurb said:
The ecu knows if what gear the automatic is in and control lockup of the torque converter, correct?
I can move the brake safety switch to the clutch pedal?
If I’m using my existing steering column what would I need to alter(it’s a column shift now, of course)?
Click to expand...
The wiring under the dash at the top of the steering column has 2 pairs of wires IIRC one for neutral on an automatic and one for the safety switch for a manual.
I believe bob @diesel4me knows which is which.
You just need to hook it up to the switch on the clutch.
Don't touch the brake switch.
 
imiceman44 said:
The wiring under the dash at the top of the steering column has 2 pairs of wires IIRC one for neutral on an automatic and one for the safety switch for a manual.
I believe bob @diesel4me knows which is which.
You just need to hook it up to the switch on the clutch.
Don't touch the brake switch.
Click to expand...
Nice, thanks!
 
I am looking at cutting the floor for the SM465 shifter. There is an indent in my floor towards the front and a but to the driver side of the transfer case shifter. Pictures weren’t turning out well. I am I correct in assuming this is what was cut out on the manual transmission trucks and cutting along this will work?
 
My 91 Blazer had an oval-ish indent in the tunnel that matches the shifter boot mounting ring. The indent even had dimples for screws. Mine was centered and about 6"-8" forward of the tcase shifter, roughly even with the bottom of the dash.
 
nvrenuf said:
My 91 Blazer had an oval-ish indent in the tunnel that matches the shifter boot mounting ring. The indent even had dimples for screws. Mine was centered and about 6"-8" forward of the tcase shifter, roughly even with the bottom of the dash.
Click to expand...
Sounds like it.
 
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