What have you done to your square lately??

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AyWoSch Motors

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Ayden
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1986
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K1500 Sierra
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350ci V8
Back when I got the truck 13 years ago, I aquired a th400 core and an np205 to have my favorite trans shop (Metro Transmission in Columbus OH) go through because I wanted to get rid of the np203. It's been under the work bench (in 3 different garages now, lol) ever since, just waiting for me to use it. I feared that after sitting so long, it may not work properly, but it turns out that it does.
How direct of a swap is a 203 to 205?

My blazer has a 203 full time, and i want to make it a offroad race truck. Picked up a free 205 the other day, been thinking of putting it in there.
Is it a straight 1 for 1 swap, or....
 

Bextreme04

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Eric
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1980
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K25
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350-4bbl
Beats me. All the silvery glittery stuff is aluminum particles I believe. Other than the pump whine type noise, it shifted perfectly right up until it didn't shift at all.

I'd assume the filter wasn't plugged since there was enough line pressure to shift properly. Isn't the filter seal below fluid level?
Filter seal is well above the fluid level. Fluid level should be at the pan rail when full. Filter seal is well above the pan rail. Also, I get a pump whine when cold and using the cheap garbage synthetic element filters that everyone sells. I had to switch to the brass element filled high flow filter in order to get rid of the pump whine.
 

Bextreme04

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K25
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350-4bbl
How direct of a swap is a 203 to 205?

My blazer has a 203 full time, and i want to make it a offroad race truck. Picked up a free 205 the other day, been thinking of putting it in there.
Is it a straight 1 for 1 swap, or....
Not direct, at all. Different adapter, different shaft spline counts, different length for the front and rear driveshafts, different shift linkages and shifters.
 

bucket

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How direct of a swap is a 203 to 205?

My blazer has a 203 full time, and i want to make it a offroad race truck. Picked up a free 205 the other day, been thinking of putting it in there.
Is it a straight 1 for 1 swap, or....

If you have a th350, it's not a big deal IF you get a complete setup with adapter and shifter from another th350 truck. They are 27 spline.

You can also use a 10 spline 205 from behind a 465, but you need a conversion sleeve in addition to the th350 adapter.

If you have a th400, it's a no-go unless you change the trans or the output shaft in the trans. Then you also need the expensive 32 spline 205 and matching adapter for the output shaft length length you have.
 

AyWoSch Motors

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K1500 Sierra
Engine Size
350ci V8
If you have a th350, it's not a big deal IF you get a complete setup with adapter and shifter from another th350 truck. They are 27 spline.

You can also use a 10 spline 205 from behind a 465, but you need a conversion sleeve in addition to the th350 adapter.

If you have a th400, it's a no-go unless you change the trans or the output shaft in the trans. Then you also need the expensive 32 spline 205 and matching adapter for the output shaft length length you have.
Well i have a SM465
 

AyWoSch Motors

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K1500 Sierra
Engine Size
350ci V8
If you have a th350, it's not a big deal IF you get a complete setup with adapter and shifter from another th350 truck. They are 27 spline.

You can also use a 10 spline 205 from behind a 465, but you need a conversion sleeve in addition to the th350 adapter.

If you have a th400, it's a no-go unless you change the trans or the output shaft in the trans. Then you also need the expensive 32 spline 205 and matching adapter for the output shaft length length you have.
Well i have a SM465
 

bucket

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Well i have a SM465

You currently have a 465 with a 203? Pretty uncommon. The forward part of that particular 203 and the adapter used to be valuable for doubler swaps, but I'm not sure anymore. Theres other gearing options now.

But if so, you would want a 10 spline 205 and the 465/205 adapter. That's the most common one.
 

Redfish

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I added a little bit of refrigerant to the A/C system. That may seem like a very insignificant thing but...

BigUn/Mrs. Redfish is having her 40th class reunion tomorrow night. She thinks it might be cool to bring The '87 to her Class of '83 Reunion.

I have long suspected that my super cheap refrigerant gauge was not exactly accurate. I have checked the pressure several times on The '87 because the A/C doesn't cool quite as well as I want it to. Factor in the record setting heat, Mrs. Redfish's very long hair... A couple of recent uses really had me questioning my gauge. I added just a bit more and Oh My! Suddenly I have A/C that actually cools the truck!
 

AyWoSch Motors

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You currently have a 465 with a 203? Pretty uncommon. The forward part of that particular 203 and the adapter used to be valuable for doubler swaps, but I'm not sure anymore. Theres other gearing options now.

But if so, you would want a 10 spline 205 and the 465/205 adapter. That's the most common one.
Didn't know that. Good to know.

Yes my 75 blazer is 454, 465, 203, fulltime dana 44 front, 12 bolt rear. Weird setup truck.
I actaully have a whole other 465 203 combo in my parts pile too
But my 205 i have, that i wanted to swap in, is already paired up with another 465 (lower mileage too) so id likely just swap them both together. I also have the front driveshaft that went with that transfer.
So it sounds like id need a differnt rear driveshaft....
Is the cross member the same?
 

bucket

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Didn't know that. Good to know.

Yes my 75 blazer is 454, 465, 203, fulltime dana 44 front, 12 bolt rear. Weird setup truck.
I actaully have a whole other 465 203 combo in my parts pile too
But my 205 i have, that i wanted to swap in, is already paired up with another 465 (lower mileage too) so id likely just swap them both together. I also have the front driveshaft that went with that transfer.
So it sounds like id need a differnt rear driveshaft....
Is the cross member the same?

If it's a figure 8 pattern 205 setup (pre-'85) then yeah the crossmember is the same.
 

PrairieDrifter

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Suburban k10, bonanza k10, k30, k20, c10, gmc 1/2ton
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350, 350, 350, 350, 350, 350
Didn't want to start a thread, and the wiring diagram isn't helping. 84 burban manual windows and locks.

This is a tan wire, not brown, not yellow. The pic is bad. It has a quick connect that's kinda on top of the fuse lock, that runs into the main harness, that looks like it goes to the instrument panel harness.

But also the strange part. It runs into the kick panel grommet for the dome light door jamb switch, on the drivers side. It's meant to be there, it has a two wire plug.

Now that im typing this, I think it's for the door ajar light, if it woulda even had that in 84. Would the door jamb switch had a dual plug setup? But even then, why would the door ajar need a quick disconnect?? Unless it's for the mechanics? lolol

The wiring diagram doesn't show a tan or door ajar. Even if it was brown, I don't have an ecm. The one tan says oil pressure switch, but that wouldnt run into the door jamb.

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Ontheboulder

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colville,wa
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greg
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1987
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gmc sierra classic v2500
Engine Size
350
well since the carport got done, then onto the garden rebuild,lots of do nothing days due to the heat and then the john deere riding mower of 20 years decided to spring a oil leak!!! So pulled the engine and put new gaskets and seals in it even got a new muffler to quiet it up!! hopefully good for another 10 years!! And the GMC is still waiting for me to get something done on it!!
 

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