Will 1997 c2500 5.7tbi 2wd extended cab 5 speed drive train work in 1994 c1500 single cab 4.3 tbi automatic?

[Edson]

I have owned a 1994 GMC Sierra single cab short bed with the 4.3tbi and automatic tran good but just really slow, this weekend I purchased a 1995 Chevy c2500 extended cab with a 5.7tbi and 5 speed manual transmission. My concern is what all will be different between those two year models and what will I have to change beside motor mounts and radiator

 

[1998_K1500_Sub]

The thread title says 1997 c2500 but above you said 1995.

Which is it?

You said it’s TBI so… 1995, yes?

Look in the glove box of both for a GM sticker that lists the production codes... there may be perhaps 60 three letter codes on that sticker. Look for any of these specifically and post them:

- MW3 (NV4500 manual transmission)
- M50 (NV3500 manual transmission, wide ratio, 4x4 applications)
- MG5 (NV3500 manual transmission, close ratio, 2x4 applications)

You quite possibly have the same transmission in each, MG5, although clutch may differ.

While you’re at it look for the rear end ratio RPO:
- GT4 (3.73 final gear)
- GT5 (4.10 final gear)
- GU4 (3.08 final gear)
- GU6 (3.42 final gear)

This info might come in handy later.

Quite possibly you have the 16197427 ECU in both trucks; you can look on each to find and compare their part numbers.

Regardless, you could reuse the 1995 ECU in the 1994, and you’ll certainly use the MEMCAL (“chip”) from the 1995.

Whether the engine wiring harness is exactly the same, that’s still for debate. I seem to remember they used different knock sensors (two on 4.3 vs one on 5.7… or maybe the other way around), so wiring there may differ.

All accessories should fit and function.

Hopefully others will comment further.

 

[Edson]

The thread title says 1997 c2500 but above you said 1995.

Which is it?

You said it’s TBI so… 1995, yes?

Look in the glove box of both for a GM sticker that lists the production codes... there may be perhaps 60 three letter codes on that sticker. Look for any of these specifically and post them:

- MW3 (NV4500 manual transmission)
- M50 (NV3500 manual transmission, wide ratio, 4x4 applications)
- MG5 (NV3500 manual transmission, close ratio, 2x4 applications)

You quite possibly have the same transmission in each, MG5, although clutch may differ.

While you’re at it look for the rear end ratio RPO:
- GT4 (3.73 final gear)
- GT5 (4.10 final gear)
- GU4 (3.08 final gear)
- GU6 (3.42 final gear)

This info might come in handy later.

ECU may be the same; you can look on each to find and compare their part numbers.

Regardless, you could reuse the 1995 ECU in the 1994, and you’ll certainly use the MEMCAL (“chip”) from the 1995.

Whether the wiring harness is the same, that’s still for debate. I seem to remember they used different knock sensors (two on 4.3 vs one on 5.7… or maybe the other way around), so wiring there may differ.

All accessories should fit and function.

Hopefully others will comment further.

The thread title says 1997 c2500 but above you said 1995.

Which is it?

You said it’s TBI so… 1995, yes?

Look in the glove box of both for a GM sticker that lists the production codes... there may be perhaps 60 three letter codes on that sticker. Look for any of these specifically and post them:

- MW3 (NV4500 manual transmission)
- M50 (NV3500 manual transmission, wide ratio, 4x4 applications)
- MG5 (NV3500 manual transmission, close ratio, 2x4 applications)

You quite possibly have the same transmission in each, MG5, although clutch may differ.

While you’re at it look for the rear end ratio RPO:
- GT4 (3.73 final gear)
- GT5 (4.10 final gear)
- GU4 (3.08 final gear)
- GU6 (3.42 final gear)

This info might come in handy later.

ECU may be the same; you can look on each to find and compare their part numbers.

Regardless, you could reuse the 1995 ECU in the 1994, and you’ll certainly use the MEMCAL (“chip”) from the 1995.

Whether the wiring harness is the same, that’s still for debate. I seem to remember they used different knock sensors (two on 4.3 vs one on 5.7… or maybe the other way around), so wiring there may differ.

All accessories should fit and function.

Hopefully others will comment further.

Okay I will check tmr and post the codes and sorry I meant 1995 not 1997 and yeah I’m not real quite sure if the engine harness will plug in as the 94 has boxy dash interior And 95 has more round dash interior

 

[RichLo]

It certainly helps that you have a complete donor truck that you can use for the swap.

With some time and patience everything can swap over from the 95 5.7 manual to the 94 4.3 auto. You're current driveshaft may fit the 5-speed but you should measure both transmissions from the bellhousing to the output shaft to see if they are the same length.

 

[Edson]

Okay thanks for the info will measure and my biggest concern was that I’m not sure if the engine harness will plug up from the 95 into the 94 and I really prefer the boxy interior over the 95s interior

 

[tlr1093]

The thread title says 1997 c2500 but above you said 1995.

Which is it?

You said it’s TBI so… 1995, yes?

Look in the glove box of both for a GM sticker that lists the production codes... there may be perhaps 60 three letter codes on that sticker. Look for any of these specifically and post them:

- MW3 (NV4500 manual transmission)
- M50 (NV3500 manual transmission, wide ratio, 4x4 applications)
- MG5 (NV3500 manual transmission, close ratio, 2x4 applications)

You quite possibly have the same transmission in each, MG5, although clutch may differ.

While you’re at it look for the rear end ratio RPO:
- GT4 (3.73 final gear)
- GT5 (4.10 final gear)
- GU4 (3.08 final gear)
- GU6 (3.42 final gear)

This info might come in handy later.

Quite possibly you have the 16197427 ECU in both trucks; you can look on each to find and compare their part numbers.

Regardless, you could reuse the 1995 ECU in the 1994, and you’ll certainly use the MEMCAL (“chip”) from the 1995.

Whether the engine wiring harness is exactly the same, that’s still for debate. I seem to remember they used different knock sensors (two on 4.3 vs one on 5.7… or maybe the other way around), so wiring there may differ.

All accessories should fit and function.

Hopefully others will comment further.

Just curious but I have a 4.3 tbi with the nv3500 and the motors tired! Could I replace my 4.3 computer with the 5.7 automatic computer and it work?

 

[1998_K1500_Sub]

Just curious but I have a 4.3 tbi with the nv3500 and the motors tired! Could I replace my 4.3 computer with the 5.7 automatic computer and it work?

Check the part numbers on the computers. If they're the same, AFAIK the answer is "Yes". In the later models (I think 1994-1995) you *will* need to swap the MEMCAL (pictured below) from the original ECU to the replacement.

In the earlier models (prior to 1994?) there's a similar module(s) that need to be swapped.

Too, you may be able to (re)use the 4.3L's computer, but with the 5.7L's MEMCAL and wiring harness... or, perhaps with some minor wiring harness changes. I think the 1994-1995 4.3Ls used two knock sensors and the 5.7Ls used one, or vise versa... but it is pretty trivial IIRC. I replaced a 4.3L in my 1995 S10 with a 5.7L and only the knock sensor wiring was different. The thing to do IMHO is get a factory service manual for your year and investigate the differences b/t the two engines' wiring.

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Below is the image of common ECU for the 1994/1995 model years. Note the part number is evident on the sticker (16197427 in this case). Your ECU's part number may be different. The MEMCAL used in this ECU is behind that panel at the top, affixed by two screws. The picture given above shows the ECU with the panel removed and the MEMCAL visible.

You must be registered for see images attach

 

[tlr1093]

Sorry I left soooo much context out, the truck is a 1992 c1500 ext cab with the v6 but I have a running 5.7 tbi out of a 93 I believe. I also did some more research and people are say all I should need is a prom for the 350 off eBay. Pre 94 of course

 

[PlayingWithTBI]

I also did some more research and people are say all I should need is a prom for the 350 off eBay. Pre 94 of course

The EPROM needs to be from the same Service Number PCM, you can't mix them from one to another.