C3 transmission change
Thread Starter
Advanced
Joined: Nov 2012
Posts: 53
Likes: 1
From: Oshkosh Wisconsin
C3 transmission change
Had a recent minor engine fire in our 1979. Will probably rebuild the engine as it has minimal miles on it. Would like to change the automatic to newer one that has an overdrive. Is there one that is the same length and same output shaft splines?
Drifting
Joined: Aug 2005
Posts: 1,682
Likes: 3
From: League City TX
200 4r is about the same length, and has the same splines.
The trans mount location is further back, but you can either modify your crossmember if you have metal working skills, or you can buy an aftermarket crossmember designed for the swap.
The trans mount location is further back, but you can either modify your crossmember if you have metal working skills, or you can buy an aftermarket crossmember designed for the swap.
Thread Starter
Advanced
Joined: Nov 2012
Posts: 53
Likes: 1
From: Oshkosh Wisconsin
Thanks for the tip. I think we will look for a 200 and go that way.
Team Owner
Joined: Jul 1999
Posts: 65,492
Likes: 230
From: Orange Park Florida
it is NOT a 200, it IS a 200 4r, a 200 is a weak 3 speed trans....it's basic setup was used and toughened up a bit and the o/drive added....you want one from a Monte Carlo outta the 80's....
when you rebuild it, you want to add a TRANS GO shift kit....when you get it in the car, we can help you with the lockup converter wiring,.....
Safety Car
Joined: Jan 2009
Posts: 3,736
Likes: 56
From: anchorage ak
it is NOT a 200, it IS a 200 4r, a 200 is a weak 3 speed trans....it's basic setup was used and toughened up a bit and the o/drive added....you want one from a Monte Carlo outta the 80's.... when you rebuild it, you want to add a TRANS GO shift kit....when you get it in the car, we can help you with the lockup converter wiring,.....
Thread Starter
Advanced
Joined: Nov 2012
Posts: 53
Likes: 1
From: Oshkosh Wisconsin
Thanks, everyone. Debating on putting newer engine in and leaving tranny alone or dressing up engine and replacing tranny with 200 R4. Thought taller 1st gear and OD would be nice.
Instructor
Joined: Jun 2006
Posts: 146
Likes: 5
From: North Brunswick New Jersey
The 2004r in a '79 is an easy swap as the bolt-in cross member does not have to be changed or modified. Just take off(unbolt) the bracket for the TH350 tail mount and notice that the holes drilled in the cross member line up with the rear mount on the 2004r. You'll have to read up on the correct set-up for the TV cable to carb on say,.. the Bowtie Overdrives web site for clarification. The speedo gear may have to be changed but the cable hooks right up. I gotta say, it's like having a new car again with the overdrive in. Good luck with whatever you do.
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Melting Slicks
Joined: Oct 2011
Posts: 3,453
Likes: 67
From: Midland Ontario
NCM Sinkhole Donor
FWIW I found one this summer and will be rebuilding over the winter. Will get all necessary parts from BowTie Overdrives and have it ready to go hopefully next spring. I found mine for $200.
Burning Brakes
Joined: Oct 2010
Posts: 1,192
Likes: 7
From: Wentzville MO
2004R is the easiest swap. You don't have to change anything with the crossmember. Just remove the tranny mount plate and reuse the rubber upper mount. I have done it a couple of times on my 78.