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Old 12-11-2009, 07:00 AM   #1
Gyoas759
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TH400 vs. 700R4. Which is better?

Just wondering what the advantages and disadvantages are to each tranny and if one has shown itself any better than the other. I originally thought I had a 700R4 trans in my 89 3/4 ton burb, but yesterday when I was looking for a replacement pan gasket for the trans I discovered that it's a TH400. Which is better?
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Old 12-11-2009, 07:13 AM   #2
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This could be argued for days, but it depends on what you are doing. For a daily driver on the highway a 700R4, for a mudder truck definitely the TH400. For any rig it's going to depend on the purpose.

The TH400 is much stronger, but it doesn't have overdrive and the first gear is only 2.48:1.

The 700R4 has an overdrive gear (0.7:1), and a 3.06:1 first gear, but it's not as strong.

So it depends on what your using it for and how much power you have. If you need an overdrive with the strength of the TH400 you want a 4L80E.
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Old 12-11-2009, 07:14 AM   #3
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700R4 is a 4 speed (overdrive) but not as strong as the TH400
TH400 is a strong 3 speed
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Old 12-11-2009, 07:35 AM
Posted in reply to Keitha's post starting "700R4 is a 4 speed (overdrive) but not..."
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My #1 priority is durability. I want this truck to last and last. It will be used as a secondary vehicle for when is uses are asked for - towing, some light to moderate off roading and trips when the 9 seater capacity will be called upon. Not looking much for speed or performance. (though I wouldn't mind it.) Just looking for rugged durability. The truck has only 48k on it. I'd like it to see 250k on this same set up.
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Old 12-11-2009, 07:44 AM
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Stick with the TH400 - they were standard in the 3/4 ton Subs until 1991 model year when the 4L80e was introduced. The 700r4 only came in the 1/2 tons.
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Old 12-11-2009, 09:14 AM
Posted in reply to Keitha's post starting "Stick with the TH400 - they were..."
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Stick with the TH400 - they were standard in the 3/4 ton Subs until 1991 model year when the 4L80e was introduced. The 700r4 only came in the 1/2 tons.
AFAIC....the only adavantage to the 700R4 is lower first gear, and overdrive. Other than that a POS....

And they put them in at least some 7200GVW 3/4 ton also.
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Old 12-11-2009, 09:29 AM
Posted in reply to 76zimmer's post starting "AFAIC....the only adavantage to the..."
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AFAIC....the only adavantage to the 700R4 is lower first gear, and overdrive. Other than that a POS.....
How so? That is a broad statement. It's pretty simple, the TH400 is stronger, the TH700R4 has overdrive. If you are planning on using the Suburban for long distance trips, the overdrive would be nice. There is absolutely nothing wrong with a nicely built TH700R4. Calling it a POS is very ignorant.Martin
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Old 12-11-2009, 09:49 AM
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The 700r is a great trans. It is basically a TH350 with overdrive.

I have 2 Blazers, one has a TH350 the other a 700r. Needless to say, but the 3 speed one stays parked and is only used off-road. I can't afford the gas to drive it on the highway. Have you ever heard the expression, "I can pass anything but a Gas Station." With the 4 speed I can do 70mph and still get about 15mpg.

Now having said that, If I were you I wouldn't bother swapping a transmission. Why? Well, the hassle and cost involved is NOT worth the results. You have to have the right T-case adapter, front and rear driveshafts, kickdown setup, and on and on.

It's not worth the swap unless you tranny is blown and you have a donor vehicle with everything you need.
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Old 12-11-2009, 07:03 PM
Posted in reply to hotrodbill's post starting "The 700r is a great trans. It is..."
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READ: AFAIC.....(meaning my opinion from someone who has owned one)
Well for one thing you have to have enough engine to pull a 700R4 at highway speeds. A 305 don't do that very well unless empty. My truck wasn't an everyday commuter, so when I did drive it at highway speeds it wasn't empty, so that meant it was hunting for a gear appropriate to the speed I was trying to maintain. Pulling a 7000lb. trailer meant pulling in Drive anyways, yielding 7-8 mpg while doing 70 mph (with 3.73 gears). In 85 you could only get a 350 if you ordered a HD 3/4 ton (C6P option). That meant 8600 gvw. Then you couldn't get an overdrive trans. to go with the 350 engine. So basically the 700R4 option was worthless to me....read again AFAIC!!! I'm not saying it doesn't have its place, but for a towing truck I do believe its worthless as a stock 4L60E, which it basically is without all the electronic functions. The GVW of that trans was rated at 11,400lbs. and that was only if you didn't use the OD capability.
Practically any trans could be made into a decent, or desirable trans. given enough money, but a 400 would win hands down, overall, in a stock (as produced) environment.
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Old 12-11-2009, 10:59 PM
Posted in reply to 76zimmer's post starting "READ: AFAIC.....(meaning my opinion..."
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Jees !! The 700r4 was never designed to be a HD towing trans. That is why it was put in 1/2 ton trucks/ cars and some light duty 3/4 tons DuuuuH!
It was a light duty trans that did what it was designed for very well.(well.. errrr...... after it was modified in 88)
Later model post 88 700s are just as strong or better as a TH350.
I dont understand why you are slamming them. They are a good trans.
yeah they are not a TH 400 or 4l80E
But i have blown more Th350s and TH400s than 700r4s in my trucks.
Course i have been around a lot longer than the 700s and have had more oppurtinuitys and engines built to blow 400s.
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