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#1 |
Can't ReMember
Join Date: Dec 2006
Location: Orlando area
Posts: 258
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200-4r and towing
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
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Adversity doesn't test your character; it reveals it. 71 C-10 LWB 350/TH350. I purchased it in 1978 for $1400. I'm currently abusing it daily. (when it's running ![]() |
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#2 |
Son of a gun
Join Date: Jan 2007
Location: Hot Springs, Arkansas
Posts: 1,636
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Re: 200-4r and towing
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.
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Bill BEATERS ARE NEATER |
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#3 |
Can't ReMember
Join Date: Dec 2006
Location: Orlando area
Posts: 258
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Re: 200-4r and towing
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
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Adversity doesn't test your character; it reveals it. 71 C-10 LWB 350/TH350. I purchased it in 1978 for $1400. I'm currently abusing it daily. (when it's running ![]() |
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#4 |
Registered User
![]() Join Date: Nov 2002
Location: Lebanon, Tennessee
Posts: 1,372
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Re: 200-4r and towing
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
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Jeff '67 short Fleet; my ongoing project. '66 long Fleet; my original "baby." Live life or bust trying. Last edited by Truckstr; 07-03-2007 at 08:00 PM. |
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#5 |
Can't ReMember
Join Date: Dec 2006
Location: Orlando area
Posts: 258
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Re: 200-4r and towing
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?
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Adversity doesn't test your character; it reveals it. 71 C-10 LWB 350/TH350. I purchased it in 1978 for $1400. I'm currently abusing it daily. (when it's running ![]() |
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#6 | |
Registered User
![]() Join Date: Nov 2002
Location: Lebanon, Tennessee
Posts: 1,372
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Re: 200-4r and towing
Quote:
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.
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Jeff '67 short Fleet; my ongoing project. '66 long Fleet; my original "baby." Live life or bust trying. |
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#7 |
Can't ReMember
Join Date: Dec 2006
Location: Orlando area
Posts: 258
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Re: 200-4r and towing
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. ![]()
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Adversity doesn't test your character; it reveals it. 71 C-10 LWB 350/TH350. I purchased it in 1978 for $1400. I'm currently abusing it daily. (when it's running ![]() |
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#8 |
Scrapper 1
Join Date: Jan 2007
Location: Riverside Calif
Posts: 1,649
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Re: 200-4r and towing
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
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#9 |
Registered User
Join Date: Dec 2006
Location: Rhode Island
Posts: 602
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Re: 200-4r and towing
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
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69 C-10 SWB Fleetside 454/TH400 (For Sale) http://67-72chevytrucks.com/vboard/c...ct=1299&cat=12 70 El Camino 454 TH700 29 Model A 4-DR Sedan Deluxe |
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#10 | |
Registered User
Join Date: Feb 2000
Location: Center City, MN, USA
Posts: 3,254
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Re: 200-4r and towing
Quote:
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'70 cab, '71 chassis, 383, TH350, NP205. '71 Malibu convertible '72 Malibu hard top Center City, MN |
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#11 |
Old Skool Club
![]() Join Date: Jun 2001
Location: Benton, AR "The Heart of Arkansas"
Posts: 10,880
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Re: 200-4r and towing
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.
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Member Nr. 2770 '96 GMC Sportside; 4.3/SLT - Daily driven....constantly needs washed. '69 C-10 SWB; 350/TH400 - in limbo The older I get, the better I was. |
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#12 |
Can't ReMember
Join Date: Dec 2006
Location: Orlando area
Posts: 258
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Re: 200-4r and towing
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 ![]() ![]()
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Adversity doesn't test your character; it reveals it. 71 C-10 LWB 350/TH350. I purchased it in 1978 for $1400. I'm currently abusing it daily. (when it's running ![]() |
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#13 | |
Registered User
Join Date: Dec 2006
Location: Rhode Island
Posts: 602
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Re: 200-4r and towing
Quote:
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.
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69 C-10 SWB Fleetside 454/TH400 (For Sale) http://67-72chevytrucks.com/vboard/c...ct=1299&cat=12 70 El Camino 454 TH700 29 Model A 4-DR Sedan Deluxe |
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#15 |
Senior Member
Join Date: Nov 2005
Location: northwestern wi
Posts: 2,111
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Re: 200-4r and towing
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
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