I have a stock 95 Suburban 1500, 350 with a 4L60 that I use as a daily driver. I have burnt the 4L60 out twice and found from some asking around that they are a very weak tranny. Does anyone have a cheap trick or solution or know of a post that discusses this?
I am gonna bet that this is either driver error or a shitty rebuild. These trannies are just fine in a stock rig. My service truck has it and its original with 285k on it, my Tahoe thats lifted has 150k still orighinal and pops 95 sub has 290k and also never been touched. I have owned numerous rigs with this trans and only 1 has ever failed. It was my driving like a jackass through the hills that caused it.
Not true its hit or miss for the untouched 4l60. But that said if its rebuilt the rebuilder has alot to do.
For the OP I would look at doing a 4l80e swap. Really easy if its a 2wd truck. But it would be just rewiring the trans. for the 80 and burning the chip. Then shorting the rear DS. The 4x4 is little more work.
Short of the swap just find a good rebuilder that use decent parts.
I drive with a light foot in this truck. The truck rarely leaves pavement and occasionally hauls a small trailer with a dirtbike on it for a short distance. I had 100k on the tranny the 1st time and only 23k after I had it rebuilt. (the rebuilder was an idiot and I have a new tranny guy)
My step dad has gone through 5 4L60s in 5 years, my boss's brother just burnt his out, and my friend burnt hers out awhile ago. And the tranny specialist im going to now who has a well established shop even told me they are a horrible tranny.
I asked about swapping to a 4L80, a newer 4L60 (96 was stronger apparently), or an older 700R4 and I was told its a ton of work to do any of the swaps.
Have the 4L60E rebuilt by someone who knows that the fuck they're doing. Retrofits from later transmissions are adaptable to earlier models. Some hard parts will need to be upgraded and possibly replaced. Cheap out on it and you will be right back where you are now.
4l60s are a really good transmission within stock perameters with a good rebuild and x2 on the external cooler. no running through the radiator bullshit
are you flushing your tranny cooler? replacing your converter? is your rad leaking coolant/trans fluid together? sounds like its something other than a shitty build. or like you said possibly a shitty builder
You might want to know what the fuck you're talking about before you start pounding away on the keyboard. The 700/4L60E isn't NOT a TH350 with an OD. This is unlike a 4L80E, which IS literally a TH400 gear section with an OD added to the input side. Most of the parts downstream of the OD section of a 4L80E are interchangeable with a TH400.
The 4L60e is a th350 with overdrive and electronics. It needs a big cooler and a rebuild by a competent rebuilder. There are lots of internal upgrades available to make them damn near bulletproof. Find a reputable builder that will take the time to really diagnose the failure, correct the problem, and fine tune line pressures and everything. It will make a world of difference.
Anyone have any experience with the monster in a box rebuild kit for this tranny? With the right tools and a thorough manual could the average mechanic tackle one of these or am I nuts to even consider it? I have one in my Tahoe and its starting to slip more and more frequently.
Thanks for all the suggestions/info guys. I have a reputable builder now. Im hoping if he rebuilds it then it will last. I do have plans to maybe lift the truck in the future, but if Im having troubles with the tranny already, then I dont know about a lift and bigger tires.
Im thinkin on adding a big bad tranny cooler now that its been suggested. Are there any kits for that?
Use the largest stacked plate design cooler you can fit to the truck, be sure the lines you cut are properly flared as well. Run through the radiator cooler first, then the extra cooler and back to the trans. The top cooler line on the trans is the return line.We like the Hayden Transaver Plus as it comes with hose, mounting brackets and fittings which will make for a strong and long lasting installation. Avoid the tube and fin designs and any of those plastic mounting rigs that push through the radiator fins. As others have stated, the 4L60E can be a durable transmission in this application, you just need to have a builder that knows weak points and can upgrade and update as reqyuired to make this trans the best it can be.
Without knowing what the failure was when the trans went out the first time after 100K, and the next lasting less than 30K sounds sketchy to me. You haven't answered important questions like "was the torque converter replaced?" or "has the cooler been flushed and flow tested?".
The converter will collect a shit load of metal flakes and such in the bottom of it. If not replaced after a failure and it has shit in it guess where it goes the first time you start the truck? Same with the cooler, if not flushed properly and the flow rate tested (most good trans builders will supply this information) your just putting the metal back in the transmission.
If the 4L60E/700R4 was just a "junk, weak" transmission then the basic design would not have been used since the mid '80's on... whoever told you the transmission is junk is a fuckin' idiot.
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Related Threads
?
?
?
?
?
Pirate 4x4
18.7M posts
366.4K members
Since 2000
A forum community dedicated to custom off-road vehicle owners and enthusiasts. Come join the discussion about trail reports, builds, performance, modifications, classifieds, troubleshooting, fabrication, drivetrain, and more!