Th350 vs. 700R4

I would like to know, from a four wheelers perspective, which is better? the Th350 or the 700R4. thanks.


coot.

A recent article in Petersen's 4-Wheel seemed to favor the 700 because its first gear was lower than the 350, which in turn was lower than the 400. Can't remember which issue.
Pete

I love my 700r4 wouldn't trade anything for it, It's low gear is great...White Knight CLRR

I had a 700R4 stock in my 85, it was great until I went bigger than 33" tires. It couldnt keep me up to highway speed without shifting incessantly from overdrive to 3rd back and forth. The slightest little grade and it would shift down and I would keep losing speed until the top. I changed my axles to 4:56 and it helped a lot but it still wanted to hunt around at hiway speeds. I probably could have sorted it out but got a deal on a TH400 and like it a lot.
Mike


Thumper 2
85 fullsize Jimmy
ColoradoK5 Oct. Blazer of the month

I definetly prefer the 700R4. The 1st gear ratio in the 700 is around 3.0:1 versus the 350 or 400 ratio of around 2.5:1 which gives you much better off the line power and crawling ability. The overdrive gear is also nice for highway cruising. About the concerns of shifting between 3rd and 4th (OD), I only shift it into OD once out on the highway and keep it in Drive around town or on curvy rounds.
And of course, if you have big tires and stock gearing is will have more of a tendency to shift between OD and 3rd, especially on grades. I also want to address the previous post which states "it would shift down and I would keep losing speed until the top". If the 700R4 shifts down into 3rd gear, there should be absolutely no performance difference between it and the 400 because both the 3rd gear of the 700, and 3rd gear of the 400 are the same ratio of 1.0:1. I do agree that a 700 will hunt between 3rd and OD on a grade, but all you have to do is manually shift into 3rd until you get to the top.

6.2Blazer

<font color=purple> Ratios are as follows:

TH700
1st = 3.06:1
2nd = 1.65:1
3rd = 1.00:1
4th = .70:1

TH350
1st = 2.52:1
2nd = 1.52:1
3rd = 1.00:1

TH400
1st = 2.48:1
2nd = 1.48:1
3rd = 1.00:1


The wide spacing of the TH700 has an advantage when it comes to crawl-ratio & the availability of overdrive. The TH350 & TH400 make better competition trannies 'cause the spacing is better matched to acceleration, whereas the TH700 has too big of a gap from 1st to 2nd to allow the vehicle to accelerate efficiently. In terms of durability, the TH350 is probably the best overall 4x4 tranny in stock form. The TH400 is better for towing & drag racing, but is prone to breakage during full-throttle downshifts from 2nd to 1st (as would happen in deep mud, for example). This problem can be corrected with the conversion to TH475 innards. Limited applications of the TH400 also make t-case adapters scarce. While the TH700 isn't too hot in stock form, a good shop can beef one to handle a potent small-block or a mild Rat. </font color=purple>

TEX

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