2004R vs 700R4

[vmrod]

The 2004R is the exact size (length) of my TH350. I can do this swap with no changes to my driveshaft.

The 700R4 is longer, and the driveshaft would need to be shortened and the crossmemeber modified or changed.

Why do more people go with the 700R4? Is there some hidden benefit?

(by the way, this would be for a motor putting out between 250 and 375HP)

 

[Yoda]

I'll steer my ole buddy BLACKDOG to this thread. Last year he studied the is whole issue for his 1980. Ended up going with the 200R and as happy as a clam at lobster fest

Bud

 

[Bob Chadwick]

I've got a link on my web page from the "other" forum where the topic was covered pretty well. If I recall it correctly, both transmissions need some beefing up to deal with any HP increases but the real question is your rear end. Higher gearing works better with one, lower gearing works better with the other. Check out the link.

 

[MaineShark]

The 700-R4 has a more aggressive first gear. Many like this, while others say that it is too aggressive (in other words, you will only be in it for a few feet before it shifts to second).

The 200-4R has closer ratios, and a deeper overdrive.

Basically, the 700-R4 will complement a car with numerically-low rear gearing (eg, 3.08), while the 200-4R will complement a car with numerically-high rear gearing (eg, 3.55).

In general, the 200-4R seems to be the superior transmission, but it depends on your specific application. If the total gearing for each gear (transmission ratio and rear end ratio) doesn't complement your engine's powerband, either one will perform poorly.

Now, if you are willing to change your rear gearing, or already have rear gearing that will work well, then the 200-4R is the hands-down winner (in my opinion, anyway).

Joe

 

[silver 80]

anyone ever looked at the 4L60? They sell a tail housing to relocate the mount to a 200 R4. I would think all you would need then is the d-shaft.
Is it wider than a 700R4? A 4L60 is stronger isn't it? could you maybe use the new tail housing to fit on the 700R4?

 

[b_pappy]

You might check out
www.bowtieoverdrives.com
Their web-site covers a lot of Q&A's. They did the trans for my '56 Nomad, a level 2 2004R. Terrific trans. I went the lockup torque converter too, a lot of shops didn't want to mess with it, or didn't how.
Bruce

 

[patsnitrovette]

i like the low first gear (3.08)of the 700,and i also have 3.70 gears,great low end take off

 

[ohsobad]

Transmission decisions.

The 700R4, from what I know, is chosen because of the low first gear ratio of 3.06:1. That first gear really gets the car out of the hole, but the drop off to second gear is 1.54:1, third is 1.00:1, and fourth is .74:1 ratio. So if you put a 3.73:1 gearset in the rear, first gear will be 11.41:1, with fourth being 2.76:1. With that combination in your car, you will have a screamer the first three gears and some drivability for your streat machine. If you use the 200R4, you would have to use a steeper gear to get the kind of tourqe multiplication that the 700R4 provides. I'm not sure but i think the 200 has a 2.54:1 first gear ratio, so do the math and see what you are comfortable with. To get an overview of the gear ratios of the most popular transmissions, got to www.gearvendors.com .

 

[KANE]

I went with a 700R4 on my 78. Great tranny. In a light weight car (3300lbs or less) you will reap benefits from either tranny. I liked the bullit proof rebuild of the 700R4.

The selection depends on the engine, weight, and rear end.

If you look at the historical usage of the 200R4, you'd see it was the choice of tranny for the GN and GNX of the 80's. Turbocharged V-6s with lots of high end rpm band thump. That makes a big difference. That tranny, rear end, and engine were set up to spool up and make the best of a high rpm horsepower curve. It didn't need a tranny that could access a low rpm toque band.

If you look at the historical usage of the 700R4, you'd see it was the choice of tranny for the Corvettes and F-bodies. Normally aspirated V-8s with lots of low end. These cars were TPI motors that ran out of power around 5K rpm due to their design. They needed instant access to a wide, low rpm torque that was there with the 3.06 first gear.

If you have a low end torque motor.... go with the 700R4.

 

[vmrod]

Thanks for all the advice.

I really like the idea of the 2004R being a direct swap, however I have a 3.08 rear end gear, so I have to take the 700R4 into consideration as well. Although I am not just yet in the market for either one, I want to research the pros and cons of each.

 

[Glensgages]

When juggling OD swaps & rear gear swaps, I think you really need to ask yourself what are your goals.
IF you're putting a 700R4/200-4r OD trans in an earlier C3, AND contemplating a rear-gear swap, base the rear-gear on the OD-ratio. For instance...
My '82 had the 700-R4/2.87:1 combination; in OD, the .7 made it 'feel' like 2.00:1 gears. 80 MPH was 'just' 2000 RPM; even with the ridiculously-low RPM-potential of a stock Cross-Fire, that makes 120 MPH @ 3000 RPM, and 160 MPH @ 4000 RPM (theoretically).

After an August '03 swap to 3.73s, I now turn just 60 MPH @ 2000 RPM; 120 MPH, still quite high, is now 4000 RPM.
On the other hand, the 3.06:1 First Gear, and 3.73:1 rear gear, is VERY deep; pulling-out from the head of traffic at a red-light, it often shifts into 2nd gear BEFORE I CROSS THE STREET!!!

At the strip, however, the too-wide ratios of the stock 700R4 hinder performance; it 'leaps' from the line
(as much as ANY Cross-Fire can 'leap' :eyerole ),
then the RPMs drop from 4500 to 2400, and the ol' L83 can't quite 'pull' at that RPM.
It kinda 'lays-there', until it gets going again; the 2-to-3 shift, also @ 4500 RPM, results in a repeat. Because of this, I 'trap' at 90+ MPH, turning 'just' 4300, in 3rd Gear.

The deeper 3.73s allow the un-modified Cross-Fire to 'pull' to 4500 RPMs; with 1.6 rockers & true duals/no-cat exhaust, I think it'll pull to 5000 RPM legitimately, but even with 3.73s, I won't be able to 'use' it at the strip.
The increased power will make traction even-trickier; with 60' times of just 2.11-2.13 seconds, it is on the verge of spinning the 255/60R15s at the 'hit' of the throttle before any changes to the L83. I am forced to use 26" x 8" 'sticky-streets' for any and all future testing, which'll tax the aluminum Dana-44 housing...
ad
In closing, figure how many RPM you want to turn at 'what' MPH in OD, then calculate your needed rear-gear ratio...

Just my $.02 worth...

 

[vmrod]

Well, I would not be taking my car to the strip, so strip performance doesn't mean anything to me. I do like the quick launch ideas, but again, I don't need to be pulling wheelies at the stop lights. I want aggresive acceleration, and very good gas mileage while in OD. I suppose turning 3000 at 80 would be pretty good. So, what does that mean to me? Especially take into consideration that I prefer the 2004R, as it is cheaper for me to buy and an easier retro-fit.

 

[Glensgages]

...I want aggresive acceleration, and very good gas mileage while in OD...

Then, I think you'll enjoy the 200-4r automatic.

Everything in-between might suck.....ad , but the OD on the open-road is :cool !!!

 

[MaineShark]

...as it is cheaper for me to buy and an easier retro-fit.

And the money you save could be put toward changing the rear-end gearing.

With 3.08 rear gearing:
TH350 (current):
1st: 7.76
2nd: 4.68
3rd: 3.08

700-R4:
1st: 9.42
2nd: 4.99
3rd: 3.08
OD: 2.16

200-4R:
1st: 8.44
2nd: 4.84
3rd: 3.08
OD: 2.06

With 3.55 rear gearing:
200-4R:
1st: 9.73
2nd: 5.57
3rd: 3.55
OD: 2.38

So even something mild like 3.55 gears behind a 200-4R give you very nice overall ratios (even more aggressive than the 700-R4), and you would have brand new gears, too boot! The ratios are also closer (less rpm drop between gears), which makes for a nicer ride, and they are certainly better than your current TH350, so you could install the 200-4R at one point and get a nice change, then re-do the gears at a later date and get another boost

Joe

 

[vmrod]

Thanks.
That is the very info I like to hear!!