Learn Me 4L60E Rebuild/Replacement

The 4L60e in our 1998 GMC Yukon tow rig is starting to show signs of wear, like soft shifts and being slow to engage reverse.  I know basically berkeleyall about automatic transmissions, so what are my options here?  Do I want a regular rebuilt unit?  Some sort of high performance rebuild?  Online mail order?  Local shop?  Sell and buy another truck?  Manual swap?  I'm looking for the best bang for my buck, and want it to survive at least a couple more years of towing.  Even a ballpark price of what I should expect to pay for something decent would be excellent.

I asked about this a little while back. Hey, you even replied! :p

automatics are voodoo

I know, and my suggestion of a manual swap would be pretty easy- there are plenty of rusted out manual 4x4 GMT400s around I could take the necessary bits from, but I'm not sure I want a manual trans in the tow rig, or to spend that much time swapping one along with the pedals, transfer case, etc.

A good rebuild will go a long ways, and most likely be the cheaper route vs a manual conversion. I would go with a good builder that can set it up for what you are doing, towing and such. Add an additional cooler if you don't have it already.

You could swap in a 4L80e from a similar year 3/4 ton Suburban, and not have to worry about it again for towing. 

In reply to Sonic :

True, although I could probably just as easily purchase said 3/4ton and sell the Yukon.

For towing purposes I definitely prefer a manual. 

You don't have to avoid OD in a manual. 

FWIW, I have about 80-90k on a 4l80e that I "refreshed" (I just replaced the clutches and rubber seals.) in my driveway with no special tools. 

I bought a cheap rebuild guide/"manual" for it off eBay and it covered everything well enough for me to do it successfully with no prior firsthand experience with rebuilding an automatic. 

I didn't have lip seal installers, so I used strip of deburred aluminum cut off an energy drink can. 

Not the ideal way to go about it, but the hard seal installer kits are pretty pricey, and the full tool kit for it was a couple thousand dollars. 

I went with the "sell it and buy a 3/4 ton" route.  That said I looked into a lot of options before I did and the prospect of rebuilding it myself gave me the heebie jeebies. 

CL seems full of rebuilt trannies that some guy who does it all day every day sells.  Somewhere between $400 and $600 generally.  Then it's just a matter of doing the swap over a weekend or two.

¯\_(ツ)_/¯ said:

I know, and my suggestion of a manual swap would be pretty easy- there are plenty of rusted out manual 4x4 GMT400s around I could take the necessary bits from, but I'm not sure I want a manual trans in the tow rig, or to spend that much time swapping one along with the pedals, transfer case, etc.

I"m sure you have as well, but I've defiitely towed with a manual (Jesse Yuvali's diesel F250 at STPR) and did not enjoy it one bit .. Especially in a rally scenario, where a lot of your starting and stopping and pulling will be on slippery surfaces, on steep hills, in soggy fields, down a stage someplace, and such. Manual is fine if you're gonna be pulling a little utility trailer to home depot or just highway cruising. but.Automatic all the way for SUVs if you're towing a racecar around....especilly a rally car due to factors above.

As to the comment above about avoiding OD....I mean, it's not that tough. I press the button on the shifter stalk to turn it off, and I tow. I get the same mileage towing at 2500rpm as at 1800rpm anyhow in the Tree....

Just my 2 cents. Jim is all hung up on buying a manual transmisison pickup so I've already been making this argument a lot recently. But he's not gonna tow much with his....

In reply to irish44j :

I'm aware, otherwise I'd be all about the manual swap idea.  With my usual rally performance, I'm also pretty beat up by the end of the weekend, with burns on my hands, bruises all over, etc. from crawling all over the car and fixing things, so the last thing I want is to push a stiff clutch or row a clunky gearbox on my way home.

In reply to ¯\_(ツ)_/¯ :

hah, good point. I do love getting in the nice, civilized Sequoia after a rally weekend :)

One of these days the Merkur will be all sorted and you won't crash or break and will be like "damn, I feel physically great" after a rally :)

Crackers said:

For towing purposes I definitely prefer a manual. 

You don't have to avoid OD in a manual. 

 

 

That is not entirely true.  You are still running power down into the countershaft and back up to the mainshaft, which puts a whole lot more stress on stuff than just locking the input and output shafts together.  The early Dodge Cummins trucks had a Getrag, I think, five speed, and they started out with a bulletin about overfilling the trans, then they went to "Only tow heavy loads in direct drive."

A manual trans won't overheat and murder themselves as quickly as an automatic, but they may not last as long in overdrive. And, a nice modern automatic is probably smart enough to not let you murder it.

Interesting. 

Of the manual transmissions available for a GMT400 which ones shouldn't be used for towing in OD? 

I've towed untold thousands of miles in these things, and never had any issues aside from typical age related issues, so it's surprising to hear. 

Whether or not towing in OD is somewhat trans specific, but also somewhat a function of how in-tune the driver is. 

With autos, it's usually not that the trans will mechanically fail from towing in OD, but that it can lead to the trans shifting up / down a lot and in some cases spending more time running with the converter unlocked.  And if the driver isn't paying attention to trans temps and the thing doesn't have some seriously beefy cooling, it'll end up cooking itself. 

With a manual, some have a weaker top gear and can't mechanically handle sustained heavy load in the highest gear.  Others will handle it just fine. 

As a general rule, if the thing is struggling to pull steadily in the highest gear (barely any more power to give without a downshift) and it (or you) is needing to downshift a lot, just stay down a gear (you'll get about the same fuel economy anyway, at least with a gas engine, as the higher gear will keep you in constant fuel enrichment in those cases). 

If it's pulling happily in top gear with power to spare and there's no known mechanical reason to stay down a gear, let it use the higher gear and you'll save a little fuel. 

Most modern vehicles retard ignition timing during shifts which does a lot to alleviate the accelerated wear of downshifting under power. 

I've never avoided OD while towing, i just manually manage my shifts. Back when everything was a 4spd the process was either manually downshift under light power, and when it was time to upshift let off, shift up with shifter, and roll back on after it engaged. 

Assuming nothing else is already wrong, most cars don't have the sheer engine torque to burn up their own clutch packs. One notable exception in my life was my modified 3.5L Dodge Intrepid that lost 4th gear after doing 135mph wot for a while, but that trans has easily explainable physical weaknesses in 4th gear. Of course turbo diesels always came in with burned up top gears more often than the gas motors in my trans shop days, but the gas motors didn't make 500+lb ft at 1700 rpm and a LOT of diesel trucks have tuners on them. Even regarding heat, it should never go above what the cooling system can manage under steady state load unless you're in that tiny zone that exists in some cars where the torque converter unlocks but the trans doesn't downshift. An enthusiast who knows what a 'torque converter unlocking' even is would be able to drive around that too. 

Basically, #drivermod.

4l80 swap

In reply to Vigo :

The big thing to watch with converter lockup is what happens after a downshift.  Some of the older 4sp autos (like the Dodge 46RE) will only lock the converter in 4th with OD enabled in most vehicles they were used in.  If you lock out OD, then you'll get 3rd gear lockup.  With OD enabled, it'll keep the converter unlocked after a downshift to 3rd and that's when the heat problems set in. 

How much weight are you towing? How long did this trans last?

A rebuilt but improved 4L60E is probably the easy button here if the rest of the truck is in good shape. Check out Bowtie overdrives. They have some nice, but somewhat pricey stuff.

This interests me too. I've been pulling 5500lbs quite often with my Tahoe and I think the transmission isn't long for this world if I keep it up past 200k.

Does keeping the temps down prolong it? I have a nice 'n fancy radiator with an in-tank trans cooler (plus the stock auxiliary one) that keeps my temps at 140°F with a 55°F ambient, but I don't think that is the only savior.

I've ordered a couple "rebuild in a box" kits from Makco Transmission.  Their box comes with "everything you need, plus the things you will forget to order."  The prices seem pretty reasonable, and you get "performance" in a box as well.

I did a 4L60E just a year or two ago for a 4.3L S10 that was donated to the shop with a blown trans. The kit came with just that - everything.  It made it easy.  You will need a couple of special tools, but they sell those too (I made my own).

Heat is always the issue. It can be cause, or effect, but very few things fail until the lubricant gets too hot to work properly. 

Gearheadotaku said:

How much weight are you towing? How long did this trans last?

A rebuilt but improved 4L60E is probably the easy button here if the rest of the truck is in good shape. Check out Bowtie overdrives. They have some nice, but somewhat pricey stuff.

Towing around 4500lbs, in the form of a rally car on an open trailer, with a lot of weight in the tow rig itself.  This transmission is original to the truck, which has roughly 135k miles on it now- I don't know its' history prior to 100k miles (I suspect there was towing then too, given the added trans cooler), but it has spent the last 35k of them towing race cars all over the place, and being driven somewhat aggressively by me.

It's worth noting that the trans isn't cooked, and the thing is still driving all over the place currently, but this is about where the internet says they're ready to explode, so I'm trying to be proactive.

So, for an example, is this guy on craigslist an option I should consider?  The price seems right, and I could yank the trans, throw it in the back of the 318ti, and make tradesies over a weekend.  If this is going to cost me $1k+ I may consider flipping it and moving on instead, since the Yukon is probably worth at most $3k either way and I keep wanting an actual truck bed...

In reply to ¯\_(ツ)_/¯ :

If I went by "the internet says it's time for a new trans", I'd have rebuilt the Jeep trans (Chrysler 46RE) 2 or 3 times by now...  And yet it's still ticking at 235k.  

I towed 10,000lbs of Bobcat for 8 years every work day with a manual big block Ford. No problems at all. It is a viable option. Don't be a wimp.