4T60-E Auto Trans - Safe HP/Torque Limit?

[Schmieder]

Ok guys, I've looked all around and I can't find a solid answer.

What is the safest torque/hp maximum for the 4t60e auto transmission?

Considering the tranny was rebuilt 2-3 yrs ago and is in great shape, well taken care of. I also am employing a B&M Super Cooler rated at 14.4K BTU after the trans fluid passes through the radiator. Using a TRANS TEMP gauge rigged to read temps before the fluid hits any cooling unit.

Actually, two questions...

Safest torque/hp maximum?
Maximum safe temp levels?

I'm using a program called Dyno 2003. It seems precise as I entered all the general stats for my car in great detail. Camshaft, stock heads flow charts, tire radius, frontal area, ect. I got the hp/torque results in the same region as factory specs.

Now I can also input the turbo info to get an idea of hp/torque figures. Trying to hit a good strong number at the safest max the engine can handle. And I mean safest as in no catastrophic failures, increased wear and tear is expected. The block will be rebuilt or replaced in a year or two. (reinforcing internals so I can start boosting up near 20-25 psi)

Thanks for the help!

[IsaacHayes]

Before I got the orange car w/5spd I was figuring that out too, and figured I would be ok based on this:

http://www.gmtuners.com/87fiero/87fdrive.htm

Stock rebuild with modified 1-2 and 2-3 shift accumulators
Adjustable vacuum modulator
External trans coolers
70% Valvoline MaxLife DexronIII ATF / 30% CATERPILLAR 8T9572-30w Hydraulic Trans fluid

He also had the clutches tightened up by using slightly thicker metal pieces that go with the clutches (can't think of proper term). Left all torque management in the tune, and replaced all hard parts that like to wear/fail/go boom with the hardened ones.

After 6 years he said it's starting to show it's age. He said he drives it when weather is nice so it does see some use.

Avoid one wheel burnouts with these transmissions if you don't already know. That will explode them quickly.

[1988GTU]

It has earned the nick name "Sleezy E" for a reason. I highly recommend rebuilding and at the same time BUILDING the trans up with the best off the shelf parts to handle some mild power for a decent span of it's horrible life.

You will find QUICK that a good trans rebuild with GOOD parts and some reworking will cost as much if not more than an engine swap.

[Azrael]

The 4T60-E got a number of upgrades over it's manufactuing lifespan to correct certain issues. Most are backwards compatible so you can include them in a future rebuild if they haven't already done this in your last rebuild.

I think the max rated input torque was 280 lbs-ft. GM's hydro-matics are known to survive beyond this figure but reliability becomes a concern.

[mickaz]

team green lsd should help gratly trans life

[mfewtrail]

What kind of power are you looking to put through the 60-E? Anything past what the stock engines(3.4 DOHC/210hp) with this trans were rated for is probably decreasing the life expectancy on the transaxle a great deal. All things considered, how you drive it and what you use it for makes a big difference in whether it will hold up as well.

[robertisaar]

60-e doesn't like more than ~6200RPM anyways....

[Schmieder]

The Dyno Sim shows around 240 lb/ft at 3.5-4.5k RPM and 250 HP around 6.5-7k RPM.

Using a Garrett T3 T04E .5-.63 at 5psi boost in simulation.

Those ratings aren't really high but sure does kick the crap out of stock.



4T60-E supporting 240 lb/ft, 250 HP
B&M Trans Supercooler w/ temp gauge
City driving. 2-3 miles daily
Occasional yet responsible lead foot
RPM's will hardly see 6k that often

and yeah, no one wheel burn outs. I don't like paying for quality tires as often as I have too.

What is a good max temperature to base off of? Since I have the tranny temp gauge I can use that to help keep the tranny safe.

Thanks guys, I just may sport a 60degreev6 logo somewhere, like side rear window.

[Schmieder]

The 4T60-E got a number of upgrades over it's manufactuing lifespan to correct certain issues. Most are backwards compatible so you can include them in a future rebuild if they haven't already done this in your last rebuild.

I think the max rated input torque was 280 lbs-ft. GM's hydro-matics are known to survive beyond this figure but reliability becomes a concern.

Then all should be good. I'm looking at max 240-255 lb/ft

[Schmieder]

Before I got the orange car w/5spd I was figuring that out too, and figured I would be ok based on this:

http://www.gmtuners.com/87fiero/87fdrive.htm

Stock rebuild with modified 1-2 and 2-3 shift accumulators
Adjustable vacuum modulator
External trans coolers
70% Valvoline MaxLife DexronIII ATF / 30% CATERPILLAR 8T9572-30w Hydraulic Trans fluid

He also had the clutches tightened up by using slightly thicker metal pieces that go with the clutches (can't think of proper term). Left all torque management in the tune, and replaced all hard parts that like to wear/fail/go boom with the hardened ones.

After 6 years he said it's starting to show it's age. He said he drives it when weather is nice so it does see some use.

Avoid one wheel burnouts with these transmissions if you don't already know. That will explode them quickly.

Nice, I should be well in the safe area, for now, lol.

[IsaacHayes]

My N/A motor on the DD2003 simulator shows 240ft/lbs at 2000 RPM and builds from there... LOL I think it gets up to like 275 or so and doesn't drop much by 6500. 11.5:1 compression probably helps with that... I'll have to find the plot again for exact #s.

What motor are you putting a turbo on? And what car? W bodies are about 400 lbs or so heavier than L & N bodies, so that will put more wear and tear on a trans. Also a higher stall will create more heat.

If the trans is still in good shape and somewhat fresh, I'd bypass the trans cooler in the radiator totally since that is added heat into the trans along with the abuse from more power. In summer it doesn't take much to get the trans cooking with some spirited driving. In winter you want the trans to get warm though, and the stock system helps since the engine coolant warms it up. If the trans is old and seals are old, it will need to warm up before they stop leaking or you won't get into gear (mine did this and putting GM seal conditioner helped). But if the trans is in good shape, just don't beat on it until it's warmed up from driving in winter.

That added caterpillar trans fluid helps thicken the fluid a little to help coat and lubricate parts better, and also creates firmer shifts from what I was told. That's something you could try as well. And you should drop the pan and shim the accumulators as well. Sloppy slow shifts under power will kill your clutches. Adding extra springs helps too in the same way. At this time you can add the clip to hold up the differential oil tube to prevent that from falling down and then loosing oil to the diff. They sell it on one of the transmission sites online, or I've seen others use a hose clamp to hold it to the other tube from falling out. I'm not sure if your re-builder did that or not but it's a common problem. Also another easy mod is to put an adjustable vacuum modulator on the trans if yours doesn't have one already. I turned mine in 4 turns. I think mine was a black striped one. The shifts on mine after the seal conditioner (my trans has over 220,000 miles) and vacuum modulator went from long and drawn out to quick and smooth.

[pocket-rocket]

60-e doesn't like more than ~6200RPM anyways....

I was going to mention this. I've killed 2 60-e's with a DOHC, and one had a tranny cooler on it rated for something retarded like 14k GVW. IIRC my shift points were set just over 6200 RPM.

What motor are you putting a turbo on? And what car? W bodies are about 400 lbs or so heavier than L & N bodies, so that will put more wear and tear on a trans. Also a higher stall will create more heat.

http://60degreev6.com/forum/f107/need-help-with-turbo-install-t45190

"3400 v6 to fit a Garrett t3/t4? Going into a 1996 Grand Prix."

[discostu]

If the trans is still in good shape and somewhat fresh, I'd bypass the trans cooler in the radiator totally since that is added heat into the trans along with the abuse from more power. In summer it doesn't take much to get the trans cooking with some spirited driving. In winter you want the trans to get warm though, and the stock system helps since the engine coolant warms it up. If the trans is old and seals are old, it will need to warm up before they stop leaking or you won't get into gear (mine did this and putting GM seal conditioner helped). But if the trans is in good shape, just don't beat on it until it's warmed up from driving in winter.

You are generally right about most stuff, but this I'm going to have to disagree with you on Isaac.

The trans cooler in the rad is on the cold side of the radiator, and it doesn't add much heat to the transmission system (except when cold in the winter, or if your engine is overheating). Plus, a liquid cooled system like the one in the rad is much more effective at reducing temperature then an air cooled system is. That's why such a small cooler in the rad can cool a transmission effectively.

A much better option is to have the output of the rad cooler flow into a grille mounted air cooler, so you get a "double cooling" effect on the transmission fluid. The hot trans fluid enters the rad system, and gets cooled very quickly to equal the rad cold side temperature. Then it goes to the air cooler and gets cooled even more (albeit slower), resulting in nice low transmission temperatures.

[IsaacHayes]

Hmm. Very good explanation. I had not thought of the affect of fluid vs air cooling. That sounds like it makes perfect sense. The radiator is much larger even if it has to deal with the heat from the engine too.

I have to admit I have no comparison, I've only seen what the car logs in the ALDL for engine/trans temps. Plus that way you don't have to worry about TOO cold of fluid in the winter. The PCM won't even engage the TC lockup until the trans reaches a certain temperature, so yes a trans can be TOO cold.

[robertisaar]

we actually had this exact discussion on w-body a few months ago. eventually we came across a chart that shown the ideal operating temp for a tranny, can't remember where though...