200-4r and towing

[71MUTT]

There is a seal leaking real bad on my TH350. Instead of getting it rebuilt I was thinking of putting in a 200-4r. I was told that they weren't to good when it comes to towing. I'm currently not doing much towing, but might have a boat or small camper in the future. I have access to a 200 that needs to be rebuilt. Does the 200 have a transmission cooler like the TH350? Is there something I would need to get for it when rebuilding? Searched and read everything I could on the swap, just couldn't find much on towing.
This is for my 71 C-10
Thanks

[Bus Ted Knuckle]

It is going to cost you just as much if not more to rebuild the 200 as the 350...probably more. Then you have to consider your 3rd member gears, you will want to change them too (the ratio will be too tall for the overdrive). You are right about the towing properties of the 200, but it does have a trans cooler that the rest of the autos do.

I think I'd stick with the 350 and drop some money in it.

[71MUTT]

I just read a post from cdowns about his towing with a 200-4r. He said he didn't have a problem. I don't know if he had the 200 with a tow package. I checked the site out where he bought his and they do have one with a tow package. Maybe I'll see if I can get it rebuilt that way.
Anybody have any good info on the tow package?
Thanks

[Truckstr]

I can't comment on the cost to rebuild, but 200-4R trannys - if built correctly - are just as robust as TH350 trannys.

Heat is the biggest single enemy of auto transmissions. A good quality auxiliary transmission cooler is a must when towing with an auto trans.

Also, allowing it to shift in and out of overdrive while under load (read: towing) will tend to shorten the life of an over-drive equipped auto tranny.

Beyond that, you need to take into consderation what you're looking for out of your truck. Highway miles mostly? Towing a lot? Pulling your load up hills? (I notice that you're in FL, so maybe less of a concern than here in TN.)

As far as the difference between the two tranny's gearing, the TH350 has 1st=2.52, 2nd=1,52, 3rd=1.00:1. The 200-4R has 1st=2.74, 2nd=1.57, 3rd=1.00 and 4th (overdrive)=0.67:1.

Now, look at your rearend gearing. Do you know what it is? If you do, then the following equation can help you (or use a tachometer to get the RPM and solve for the gearing).

MPH = (TD x RPM) / (336 x GR) Solve it as an algebra equation for any one unknown, Ex.: RPM = (MPH x GR x 336) / TD

where TD is the Tire Diameter in inches, and GR is the Gear Ratio. Take each gear ratio in the trans and multiply it by the rearend gear ratio to get the 'GR' in the above equation. Ex.: 200-4R trans 4th gear = 0.67. If your rearend ratio is 3.73, then your GR for the above equation would be 0.67 x 3.73 = 2.4991 or 2.5:1. So, RPM at 70MPH with a 28inch tall tire would be 2100RPM versus 3133RPM with with the same 3.73 rearend gear and the TH350. Will your engine be "lugging" at 2100RPM?

If you want an already built 200-4R check here: http://www.200raptor.com/ There are others, of course.

Hope this helps!

Jeff
aka TruckSTR

[71MUTT]

So Truchstr, (or anyone, please) the math formula to figure what the gear ratio of the differential is GR = MPH x RPM x 336 / TD ? (I don't know the gearing of my differential)

Was 3.73 pretty much standard in the 71 C-10?

[stsalvage]

My thought would be the 700R4 cable the 200R4 was a car only trans and the 700R4 was a car and truck trans Me i say spend the money for a JEG's 700R4 there like 1800.00 with torq converter with shift kit not bad for a recondion 700R4

[mnunn454]

Tranny cooler required if towing, period.

Moreso if you go with the 2004R

Agree that driving in overdrive will be too much for towing, but locking it into 3rd is the same ratio in either tranny

If you think that because of the ring and pinion ratio you need/want an overdrive then get a HD TH200 and a tranny cooler and keep it in 3rd when towing. If you don't really need an overdrive, then I'd rebuild the TH350 and add a tranny cooler. JMO

[Truckstr]

Originally Posted by 71MUTT

So Truchstr, (or anyone, please) the math formula to figure what the gear ratio of the differential is GR = MPH x RPM x 336 / TD ? (I don't know the gearing of my differential)

Was 3.73 pretty much standard in the 71 C-10?

No, the correct form of the equation would be GR = (TD x RPM) / (336 x MPH).

Sorry, I know better than to write it the waty I did. I'm just not used to typing an equation out. I'll edit my original post.

Can't say about "standard" gearing, just use the equation to get it - at least get close. Error can be introduced into your calculation when measuring the tire diameter. It would probably be best to measure it from the top of the tire to the ground.

[71MUTT]

Thanks, I'll see what I come up with tomorrow.

So someone tell me. Is 2100 RPM's lugging a stock 350CID motor? I wouldn't think so, but I don't know too much.

[Truckstr]

Originally Posted by 71MUTT

Thanks, I'll see what I come up with tomorrow.

So someone tell me. Is 2100 RPM's lugging a stock 350CID motor? I wouldn't think so, but I don't know too much.

You're very welcome!

No, 2100 RPMs shouldn't lug a stock 350.

stsalvage is right, though. The 200-4R was only originally available in cars. But I've seen some pretty stout engines backed up by a 200-4R. But the same can be said of the 700-R4. Both are good transmissions. Ask around here on the boards. There are guys with all sorts of transmissions in their trucks.

Me? Well, I chose a TH350 and backed it with a Gear Vendors under/overdrive. I'm planning a new, much stronger engine and have plans to change over to a TH400 while keeping the GV. But that's another story.

[tkeduk8r]

I have a 2004r in my 74 c10 and have had NO problems even with towing a loaded doble axle moving trailer over 250 miles.... I do keep it third or direct though, but no issues at all... Im sure it has been said before but they did put them in back of Grand Nationals and they held up OK... The right trans guy can build a good trans... mine cost 550 to build and 'cept for a double shim (metal oring) placed inthe TV Cable tube hole (got stuck at Da-burbs house three summers ago) hasnt given me lick of trouble.... the install is simple too... any questions i feel pretty confident with this one.... lemme know..
--Mike

[Spray-Bomb]

whats the real difference between the 700r4 & the 200r4 ???

[wibilly]

i belive the 200 is a direct bolt in for a thm350 and the 700 is like 11/2' longer the 200's tailshaft housing is part of the case casting and is not removable and the 700's are. as for the internals i would like to know too

[mrein3]

Originally Posted by mnunn454

Tranny cooler required if towing, period.

Moreso if you go with the 2004R

Agree that driving in overdrive will be too much for towing, but locking it into 3rd is the same ratio in either tranny

If you think that because of the ring and pinion ratio you need/want an overdrive then get a HD TH200 and a tranny cooler and keep it in 3rd when towing. If you don't really need an overdrive, then I'd rebuild the TH350 and add a tranny cooler. JMO

That is pretty much all you need to know. Get an external cooler and when towing, DO NOT USE OVERDRIVE. 3rd in the 700r4 and the 200-4R is the same as 3rd in the th350 and th400. Do you know anybody that worries about towing with their th400?

[ChevLoRay]

I had an '81 Impala Wagon when I bought a 25-ft travel trailer. I didn't like the way it acted...didn't use OD. So, I bought a '76 Blazer that had a 400SB and 350TH. The Impala also had a 305 and that was a big part of the reason to get something else. I liked the 200R4 in the wagon, otherwise.

Like others have said, don't use OD when towing.

[71MUTT]

Well, I did the math and I have 3.73 gears in the rear. Picked up the 200-4r tranny today and it seems it's out of a 1986 Monte Carlo. The serial number is 275-861CRF0648. This doesn't match anything from the charts I've searched out, but what I can make out the "86" is the year, the "CR" is the internals and the "F" is for 200R4.
Now I just need to make sure it gets rebuilt properly by someone in Orlando.
Add an external cooler for towing. Don't tow in overdrive and I'll be good to go. Thank everyone for the input.

[mnunn454]

Originally Posted by 71MUTT

Well, I did the math and I have 3.73 gears in the rear. Picked up the 200-4r tranny today and it seems it's out of a 1986 Monte Carlo. The serial number is 275-861CRF0648. This doesn't match anything from the charts I've searched out, but what I can make out the "86" is the year, the "CR" is the internals and the "F" is for 200R4.
Now I just need to make sure it gets rebuilt properly by someone in Orlando.
Add an external cooler for towing. Don't tow in overdrive and I'll be good to go. Thank everyone for the input.

If I recall correctly, 85-87 TH700s are the weaker ones. Not sure if this holds true for the TH200's or not.

As far as overdrive and the 3.73 ring and pinion ratio (when not towing), you'll find it to be and excellent highway ratio.

Finally, I believe the TH200 requires a throttle valve cable in lieu of the vacuum line that the TH350 has. You'll want to pay close attention to hooking that up/adjusting it right. Otherwise, you could shorten whatever remaining life the 200 has left in it.

[71MUTT]

Thanks mnunn454. From the info that I searched out on the boards, bowtieoverdrives makes a tv cable kit to match your existing carb. They also have a switch to replace your existing brake light switch under the dash for the lockup. The TV cable adjustment is some serious sh!t. Unlike my TH350, the kickdown cable hasn't been hooked up since 1988.