Tony85cutlass

Hello fellow Cutlass owners. I have a 1985 Cutlass supreme coupe. The car has three speed transmission, and I want a four speed trans for highway. Any options/ideas??? If anyone has an idea or can let me know what would work I would be very appreciative.

Diego

You're talking about an automatic, correct?

Regardless, you should be more specific if you want to get the wisdom you're looking for.

1969w3155

His car only came w/an automatic. This car should already have highway friendly gearing.

Diego

However, we don't know how stock his car is, hence my request for clarification.

BangScreech4-4-2

He could very easily want to put a Muncie in there. Be pretty cool in a retro sort of way. I see no reason not to get some clarification. BTW, wouldn't an '85 have come with a 200R4 in the first place? So did OP or some previous owner replace it with a TH-350 ... or what? Yeah, some clarification definitely wouldn't hurt.

nsnarsk65cutlass

200r4 is a 4 speed.

rustyroger

The '85 models had a three speed transmission, I think they had a lock-up converter. Certainly my '83 wagon with a 307 did. However, replacing it with a 200r4 is a straightforward enough swap for a competent diy mechanic. Make sure you get all the ancillary parts you need, a complete donor vehicle would be ideal.
There are several threads discussing this swap, perhaps somebody could direct Tony towards some of them.

Roger.

BangScreech4-4-2

That's what I mean -- if it came from the factory with a four-speed, why would he need another one unless somewhere along the line somebody had replaced it?

70cutty

The transmission in your car is most likely th200c, which most if not all cutlass supremes came with in 85, especially the v6. If you want a 4 speed, 200r4 is a direct swap. It will use the same wiring for the lockup converter, same tv cable, driveshaft length is the same. All you have to do is move the crossmember back to the next set of holes since the mount is further back.

BangScreech4-4-2

Wow. I would have thought you got a 200R4 with all V8 applications.

joe_padavano

Not quite. The G-body cars used that screwy angled crossmember. You must use a 200-4R crossmember. You can't just slide the other one back. Also, not all G-body frames have the reinforcement needed for the 200-4R crossmember. The frame is not symmetric. Fortunately, you can get this part repro.

70cutty

Interesting, I could have sworn when we were doing the 85 (back in '96), on 85 in particular, the crossmember was the same for both transmissions and all we did was moved it back.
But I am probably wrong. Thanks for clearing it up Joe.

Tony85cutlass

Hello gentlemen. I am sorry that I didn't clarify that the vehicle I own is a three speed automatic. Is it possible that this vehicle from day one could have been a four speed, but the vehicle had an engine swap from an unknown engine to a chevy 350ci with four barrel Holley carb. I can say that the vehicle only shifts twice which leads me to believe it is a three speed. also the shifter only reads D, 2, and 1. Thank you for letting me know that the 200R4 would fit the bill. Thank you for sharing your knowledge.

Octania

for sale
1985 442
body is shot
403, 4-spd AT, 3.73:1 final drive still OK
Central lower MI

rustyroger

I think the 231 V6 motors had a th200C, larger engines had a th350C. Maybe the 200r4 was an option, but mostly '85 G bodies left the factory with a 3 speed. They were geared to cruise with a 3 speed, you might need a lower geared rear axle to get the best from an overdrive 'box.

Roger.

joe_padavano

If you are defining "G-body" as 1982-up (which is technically correct), then you are right. The 79 H/O and 80 442 came with the 350/TH350 combo, but those are actually A-body cars per GM's nomenclature. In the 1980s, the three speed AT was typically the TH200C. The 200-4R was factory-available from the 1983 H/O onward.

1969w3155

I deleted my post, to try and make sure that my info was correct, but not before you read it Joe, but I did mean newer G bodies, particularly the mid 80's Cutlasses.