G20 Tranny swap - The 1947 - Present Chevrolet & GMC Truck Message Board Network

paulbunyan · 06-03-2003, 10:24 AM

All,
I have a 1986 G20 with a THM200/4.3l in it. The tranny bangs so hard that
the vans shakes a lil bit when I put it in reverse. So I pulled a THM350 from a 1985 G20 with a 350. Now, my question is, can I simply bolt
the TH350 into my 1986 G20? Physically everything looks like it will fit, but
the wiring connector does not match up. Can anyone tell me what I need to do
to get this to fit or does anyone know what type of car has a tranny that'll
bolt right up in there. I am going back to the junkyard this Sunday so I
probably can pickup another tranny then.

paulbunyan

paulbunyan · 06-03-2003, 10:25 AM

To clarify,
The tranny bangs when I put it in reverse

**Captkaos** · 06-03-2003, 10:56 AM

Trucks/Vans were never offered with a TH200, you have a 700R4 unless it has been changed. You can swap it, but you will need to move the transmission crossmember forward. The TH350 uses no wiring. That is there for the converter lockup on the 700R4.

paulbunyan · 06-03-2003, 02:07 PM

Ok,
I may be wrong on the tranny id, here's the number on a metal tag that was riveted to the side of the tranny that came out of the van. On one line it had 303, then below that it said 86LSA11757. Does anyone know what kind of tranny it is?? And if I can use the turbo 350 on it...

paulbunyan

**Captkaos** · 06-03-2003, 03:04 PM

Yes, you can use a TH350 behind a 4.3L. You will lose overdrive though.

paulbunyan · 06-03-2003, 03:30 PM

Will the torque convertor on the tranny that came out of my van work?
How can I rig up the electrical connector on the tranny to plug into the wire on my van now?

06-03-2003, 10:24 AM	#1
paulbunyan Registered User Join Date: Jun 2003 Posts: 4	G20 Tranny swap All, I have a 1986 G20 with a THM200/4.3l in it. The tranny bangs so hard that the vans shakes a lil bit when I put it in reverse. So I pulled a THM350 from a 1985 G20 with a 350. Now, my question is, can I simply bolt the TH350 into my 1986 G20? Physically everything looks like it will fit, but the wiring connector does not match up. Can anyone tell me what I need to do to get this to fit or does anyone know what type of car has a tranny that'll bolt right up in there. I am going back to the junkyard this Sunday so I probably can pickup another tranny then. paulbunyan

06-03-2003, 10:56 AM	#3
Captkaos www.73-87chevytrucks.com Join Date: Dec 1999 Location: Birmingham, AL Posts: 6,935	Trucks/Vans were never offered with a TH200, you have a 700R4 unless it has been changed. You can swap it, but you will need to move the transmission crossmember forward. The TH350 uses no wiring. That is there for the converter lockup on the 700R4. __________________ Chris Lucas 1973 Chevy C-10 1978 GMC Jimmy (2WD) - SOLD 1987 R10 twin turbo LS 1991 R3500 SRW CrewCab 1985 K5 diesel swapped project 1989 K5 2WD conversion w/ Vette susp Project Captkaos Customs 73-87chevytrucks.com

06-03-2003, 03:04 PM	#5
Captkaos www.73-87chevytrucks.com Join Date: Dec 1999 Location: Birmingham, AL Posts: 6,935	Yes, you can use a TH350 behind a 4.3L. You will lose overdrive though. __________________ Chris Lucas 1973 Chevy C-10 1978 GMC Jimmy (2WD) - SOLD 1987 R10 twin turbo LS 1991 R3500 SRW CrewCab 1985 K5 diesel swapped project 1989 K5 2WD conversion w/ Vette susp Project Captkaos Customs 73-87chevytrucks.com

06-03-2003, 10:25 AM	#2
paulbunyan Registered User Join Date: Jun 2003 Posts: 4	To clarify, The tranny bangs when I put it in reverse

06-03-2003, 02:07 PM	#4
paulbunyan Registered User Join Date: Jun 2003 Posts: 4	Ok, I may be wrong on the tranny id, here's the number on a metal tag that was riveted to the side of the tranny that came out of the van. On one line it had 303, then below that it said 86LSA11757. Does anyone know what kind of tranny it is?? And if I can use the turbo 350 on it... paulbunyan

06-03-2003, 03:30 PM	#6
paulbunyan Registered User Join Date: Jun 2003 Posts: 4	Will the torque convertor on the tranny that came out of my van work? How can I rig up the electrical connector on the tranny to plug into the wire on my van now?



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