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4L60E - Worst transmission ever made?

1996 Chevy S-10 2.2L I4, 79K miles

Some of you might remember a while back, I posted about how the S-10 was badly misbehaving with overdrive. It would flutter in/out of lockup while going down the highway, and often times would generate massive TCC chatter when dropping out of lockup. I’ve recently had it looked at and was told the fluid had the dreaded burnt stench, and the only real fix is a rebuild. In the meantime, a fresh fluid change and a can of “stop-slip” was added. I go on my way.

It was pretty good for a few weeks, but now it’s worse than ever. It’s virtually impossible to hold it in lockup while driving on the highway and it will fight hard when trying to accelerate or even maintain speed. The last few times I pull into the driveway, transmission fluid is leaking out from multiple points around the trans case. I can drive it close to home around town and it won’t do any of that, but it seems as if the use of overdrive is causing fluid leakage.

I should also add that fuel mileage is now averaging about 18 MPG…on a 2.2 four-cylinder engine. Seems like one other possible reason the truck fights any acceleration: I bet the transmission is dragging the engine.

Now, I had the transmission simply die on me in the '94 K1500 Blazer I used to own. In that case it somehow completely overheated and cooked itself to where the casing was warped. Having heard about many other auto trans problems in numerous GM vehicles of the mid-late 90s, is it psosible that the 4L60E is the most defective transmission that’s ever seen the road?

I’m more than likely just gonna sell the S-10 for whatever I can get. I’m not too hot on rebuilding or finding another transmission.

My opinion is that the 4L60E is not the worst transmission ever made.
Did you buy the truck new or used? If used, then one has no idea exactly what the transmission went through before you bought it.

An overheating engine can also damage a transmission since the trans fluid cooler is inside the radiator.
My son has a 96 Camaro with the 4L60E and it’s been bulletproof. The only thing ever done to it has been 25-30k mile fluid/filter changes and at around 230,000 miles it’s just as solid and non-slipping as the day he bought the car.


I amnot a transmission guy (and I don’t play one on TV) but my sister put three in her 91 Caravan with the 3.3. They lasted 40-60K and they had “all the updated parts installed”, various rebuilders.


The 4L60E is as common as the TH350 except it is newer and bigger. No, its definately not the most defective transmission on the road. Most all vehicle manufacturers have their “Problem children”. When I was at the Oldsmobile GMC dealer back in the 80’s it seemed that all I ever worked on was the 440T4. They would be lined up out the door and I made a ton of money on them. They were replaced by the 4T60 and 65E’s. Aftermarket has pretty much taken over with the 4L60E’s much like the TH350’s. There are aftermarket parts I prefer to use in my overhauls of these. GM had some design flaws in these which got corrected by GM and the aftermarket. I, personally would rather have a fresh built HD 4L60E any day than some of these newer models coming on the market.

The problem you are having with yours is a very common problem. It involves the valve body and a worn TCC regulator valve. This worn valve is causing the converter clutch to slip and chatter, overheating the trans and burning the fluid. No amount of stop slip (or Fix it in a can) is going to stop that valve from leaking. When the problem starts, the first course of action is to R&R the transmission, repair the valve body, flush the cooler, install new TC and reinstall. Thats only if you catch it real early. The years which had the sunshell problems, an overhaul was recommended to upgrade it. I think if yours would have been addressed much earlier, especially with the low miles you have, a simple valve job would have been the end of it.

Hope everything works out for you.


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Yeah, I know the can stuff is only a band-aid. It’s just disturbing that it’s gotten so much worse in a pretty short period of time. I got it last year with only 55K on the clock. That few miles in 12 years tells me it probably wasn’t driven enough to even notice an issue.

Should I opt to fix it, I’d much rather replace than overhaul this one as I’m sure it’s getting pretty well roasted by this, doing god-knows-what to all the internals. I see quite a number of these units for sale on eBay from supposed good dealers, and they only run around $600 or so. I’ve bought stuff on there very often, but I’m not so sure about a transmission. Good idea or bad?

Why was she putting a GM transmission into a Dodge Caravan? That may have been the problem!

I didn’t say she installed them she just carried them around,you never know when you come upon someone who needs one.

I would vote for the old two speed power glide as the all time worse.

Has the fluid ever been changed? When was the last time it was checked? Has it been used to pull a trailer? Have you owned it since it was new?

WOW, a 4L60E with a 2.2L 4-banger!! That’s one heck of a big transmission for such a small engine! Are you sure you have a 4L60E?

Anyway, the 4L60E is generally a good transmission.

If I could get one more opinion from Transman, it’d be much appreciated.

Based on the symptoms, do you think this unit is rebuildable? I’ve had the same independent trans shop do work on other vehicles with excellent results, so if they can save it maybe I should give them a chance. It’s still got drive in all gears, so maybe it’s worth a shot. What do you think?

Joseph - did you read either of my posts? They have the answers to all of your queries except one; it has never pulled a trailer in the year I’ve had it.

Rebuildable? Absolutely, that is, of course, as long as there is no serious damage to the case. You would see this in the pan with a ton of aluminum. As far as overheating, the converter clutch will get hot when it slips but I dont see it getting hot enough to warp the case. I have seen some transmissins get so hot they actually melt the planetary gearset. I have seen clutch packs slip so bad and generate so much heat the clutches and steels will weld themselves together. I dont see this in your case. Your case and all internals are going to have to be vatted to get all the converter clutch debris out but vatting should be done in any rebuild. Dont forget about the cooler, flush it real good and check the flow rate before connecting it in to your newly rebuilt transmission. If you have any more questions, dont hesitate to ask.


95 Vette" trans. started slipping @80K miles" replaced with new 4L60E, driven only 120miles and the reverse gear within lost gear? warranty, taken care of it" drove another 400miles, lost Reverse again, and forward slippage between shifts? brought back, was repaired and had to be rebuild, with replacing lockup torque converter"=drove another 200 miles and Guess what? fluid came out of vent tube trans, top housing, found cooler plugged Within radiator, trans, over heated, wiped out dam near everything within trans" Never ever had any issues with any of our Ford trans, or Toyota" but this has o be the worst built trans. I have ever owned"

For a minute there I thought we had transman back. But no. It’s an 8 year old re-run.

l Yeah I saw a post for Transman in another thread and thought oh boy, we got a transmission expert back. What a let down.

The problem wasn’t with any of those replacement transmissions, they failed because of debris in the transmission cooler. The cooler should have been flushed before being connected to a replacement transmission. If your shop does not have a machine to flush coolers, the radiator should have been replaced.

Me too, @Rod_Knox. At least pleasant memories of transman cam back for a minute. I saw a Craig58 post a couple of days ago in another very stale thread and that felt good, too.

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When I’ve had transmissions disintegrate, the shop insisted on a new after-market cooler that by-passes the radiator. Not very expensive either.

The replacement transmissions that I installed for years came with a pressurized can of cooling system flush.

@rjcapy, the problem with your Corvette is not that the transmissions are bad. This is a labor issue in which the cooler should have been checked at the start. And if the cooler was clogged you have to assume that was due to debris and gunk from high mileage and/or lack of fluid changes.

There’s a poster on this board who says the Ford 4R70W is the worst transmission ever. Transman disagrees with that assessment as do I.

Somewhere there’s someone cursing Toyota over their shoddy transmissions…

Somewhere there’s…

The early GM 700R4 was the worst transmissions ever made. The later ones were ok.