why is the th400 better than the 4l60e?
It will take alot more abuse then a 4l60e. A T400 doesn't have an overdrive though. I drive mine on the street but ended up getting 3.50 gears since it was pretty rough on the highway.
With them both open and apart side by side there would be no doubt in your mind how the TH400 got its reputation. (And also how the 4L60-E/700R4 got theirs!)
For starters the TH400 and the 4L80-E have abolutely no aluminum power-transferring parts inside. The planetary gears are much larger. The input and output shafts dwaft the 60's. Both shifts in a 400 are clutch-packs and all 3 shifts in an 80 are too, the TH400 (and 4L80-E) do not shift with bands. (bands are used only for over-run and reverse in a TH400/4L80-E) You can get a clutch pack to transfer larg amounts of power much more linearly than a band because a band is somewhat self energizing as the rotation of the drum wraps it tighter causing it to grab which ultimately breaks hard parts and results in jolting crappy shifts. The 60's 2-3 shift is a multiple-event sequence where the band must diisengage and the 3-4 clutch pack must engage. If the timing is slightly off you will either get bog from the band not letting go fast enough or 3-4 coming in too soon, or you will get flare up from the 3-4 coming in too late or the band releasing too soon. This simply cannot happen in a TH400 or 4L80-E! Also, the gear ratios in the TH400 are close-ratio. Although the three gears don't go as deep or cover the same range as the 60, there will be no bog or flat spot after the 1-2 shift when the RPM's fall into a hole with the 4L60-E because of the huge difference in gear ratios. The TH400 will shift closer and stay in power band even with a very mild converter compared to a 60 with a very high-stall converter.
This is a 4L60-E input shaft:
This is a 4L80-E input shaft (similar to TH400):
Side-by-side:
This is the output shaft of a 4L80-E. The TH400 output is identical with the addition of the speedometer gear: (grid is 1/4" squares)
So, the TH400 is STILL a superior transmission! The only thing better is the 4L80-E in my opinion!
For starters the TH400 and the 4L80-E have abolutely no aluminum power-transferring parts inside. The planetary gears are much larger. The input and output shafts dwaft the 60's. Both shifts in a 400 are clutch-packs and all 3 shifts in an 80 are too, the TH400 (and 4L80-E) do not shift with bands. (bands are used only for over-run and reverse in a TH400/4L80-E) You can get a clutch pack to transfer larg amounts of power much more linearly than a band because a band is somewhat self energizing as the rotation of the drum wraps it tighter causing it to grab which ultimately breaks hard parts and results in jolting crappy shifts. The 60's 2-3 shift is a multiple-event sequence where the band must diisengage and the 3-4 clutch pack must engage. If the timing is slightly off you will either get bog from the band not letting go fast enough or 3-4 coming in too soon, or you will get flare up from the 3-4 coming in too late or the band releasing too soon. This simply cannot happen in a TH400 or 4L80-E! Also, the gear ratios in the TH400 are close-ratio. Although the three gears don't go as deep or cover the same range as the 60, there will be no bog or flat spot after the 1-2 shift when the RPM's fall into a hole with the 4L60-E because of the huge difference in gear ratios. The TH400 will shift closer and stay in power band even with a very mild converter compared to a 60 with a very high-stall converter.
This is a 4L60-E input shaft:
This is a 4L80-E input shaft (similar to TH400):
Side-by-side:
This is the output shaft of a 4L80-E. The TH400 output is identical with the addition of the speedometer gear: (grid is 1/4" squares)
So, the TH400 is STILL a superior transmission! The only thing better is the 4L80-E in my opinion!
TECH Regular
Joined: Feb 2004
Posts: 439
Likes: 1
From: burbank ca
ratios
Originally Posted by James B.
With them both open and apart side by side there would be no doubt in your mind how the TH400 got its reputation. (And also how the 4L60-E/700R4 got theirs!)
For starters the TH400 and the 4L80-E have abolutely no aluminum power-transferring parts inside. The planetary gears are much larger. The input and output shafts dwaft the 60's. Both shifts in a 400 are clutch-packs and all 3 shifts in an 80 are too, the TH400 (and 4L80-E) do not shift with bands. (bands are used only for over-run and reverse in a TH400/4L80-E) You can get a clutch pack to transfer larg amounts of power much more linearly than a band because a band is somewhat self energizing as the rotation of the drum wraps it tighter causing it to grab which ultimately breaks hard parts and results in jolting crappy shifts. The 60's 2-3 shift is a multiple-event sequence where the band must diisengage and the 3-4 clutch pack must engage. If the timing is slightly off you will either get bog from the band not letting go fast enough or 3-4 coming in too soon, or you will get flare up from the 3-4 coming in too late or the band releasing too soon. This simply cannot happen in a TH400 or 4L80-E! Also, the gear ratios in the TH400 are close-ratio. Although the three gears don't go as deep or cover the same range as the 60, there will be no bog or flat spot after the 1-2 shift when the RPM's fall into a hole with the 4L60-E because of the huge difference in gear ratios. The TH400 will shift closer and stay in power band even with a very mild converter compared to a 60 with a very high-stall converter.
This is a 4L60-E input shaft:
This is a 4L80-E input shaft (similar to TH400):
Side-by-side:
This is the output shaft of a 4L80-E. The TH400 output is identical with the addition of the speedometer gear: (grid is 1/4" squares)
So, the TH400 is STILL a superior transmission! The only thing better is the 4L80-E in my opinion!
For starters the TH400 and the 4L80-E have abolutely no aluminum power-transferring parts inside. The planetary gears are much larger. The input and output shafts dwaft the 60's. Both shifts in a 400 are clutch-packs and all 3 shifts in an 80 are too, the TH400 (and 4L80-E) do not shift with bands. (bands are used only for over-run and reverse in a TH400/4L80-E) You can get a clutch pack to transfer larg amounts of power much more linearly than a band because a band is somewhat self energizing as the rotation of the drum wraps it tighter causing it to grab which ultimately breaks hard parts and results in jolting crappy shifts. The 60's 2-3 shift is a multiple-event sequence where the band must diisengage and the 3-4 clutch pack must engage. If the timing is slightly off you will either get bog from the band not letting go fast enough or 3-4 coming in too soon, or you will get flare up from the 3-4 coming in too late or the band releasing too soon. This simply cannot happen in a TH400 or 4L80-E! Also, the gear ratios in the TH400 are close-ratio. Although the three gears don't go as deep or cover the same range as the 60, there will be no bog or flat spot after the 1-2 shift when the RPM's fall into a hole with the 4L60-E because of the huge difference in gear ratios. The TH400 will shift closer and stay in power band even with a very mild converter compared to a 60 with a very high-stall converter.
This is a 4L60-E input shaft:
This is a 4L80-E input shaft (similar to TH400):
Side-by-side:
This is the output shaft of a 4L80-E. The TH400 output is identical with the addition of the speedometer gear: (grid is 1/4" squares)
So, the TH400 is STILL a superior transmission! The only thing better is the 4L80-E in my opinion!
Originally Posted by john kilgore
james, you very smart guy, do you build trans's? the biggest problem with 700 type trans is second gear is low over driven- 2-4 band l have posted the math before. if you would like it again just ask. for your 4L80 2.40-1.40 ratios instead of 2.48-1.48. jk
I'm not a "trans builder" or even a "mechanic" really, but I do ALL my own work. The 4L80-E that's in my truck right now I bought off a salvage yard selling it on EBay. I rebuilt it myself nice and slow over a 1-month period. For the rebuild I used Level-10's PTS kit, also installed a TransGo shift kit, and updated the overdrive assembly to the 2001 design with an improved roller clutch. The only problem I found in this trans tearing it down was a spun bushing in the forward clutch drum for the overdrive planetary. I ended up replacing that drum because it was out of spec. It's got a B&M pan on it and a Sonnax line adapter to make the existing cooling lines work. Luckily the trans came with the dipstick and a 13" torque converter sized for a 350. I'm using the old converter with it and it locks up perfectly. I'm much happier with the 80 and the way it shifts over the 60. The same could be expected from the 400 - from first to third they're mechanically identical.
The TH400 and 4L80-E have 2.48:1 first and 1.48:1 second gear ratios stock, and there are aftermarket planetary sets available that have a 2.75:1 first and 1.57:1 second gear. These work in both the 400 and the 80, but in an 80 they must be used with a controller where the ratios can be programmed or errors will result.
The reasons I bring up the major differences in the ways 700/60 and 400/80 work is because I had a 4L60-E built with every available best aftermarket part possible. It survived 26,000 miles daily abuse without hard-parts failure. Eventually the 3-4 clutches gave out. So basically, a 4L60-E can be built to handle a lot of torque but the reality always comes back to being that it's getting overworked and just cannot last like that.
This is a pretty accurate representation of how I normally treated it:
http://james.jaguar.net/pics/launch4.mpg
