[GoremanX]

I'm pretty sure I just blew through the sun shell on my 96 RMW. I was accelerating hard from a stop, it climbed through 1st gear, shifted into 2nd, something went "bang", suddenly there was no 2nd gear and it was free-revving. I caught it in time to prevent over-revving, so the engine's fine, but I have no more 2nd, OD or reverse. Only 1st and 3rd still exist.

I would get it rebuilt, but I was planning a powertrain swap within a few months anyways, and that swap did not involve a 4L60E. I was gonna be running a 200-4R behind a Buick turbo V6. I really hate the idea of spending $2500+ on a rebuilt 4L60E when I was just planning to swap it out anyways. But the V6 isn't even close to ready yet and I need this car back up and running ASAP.

So how hard is it to run a 200-4R behind an LT1? I know I'll need to modify the transmission crossmember and change the driveshaft length (I was planning those anyways). And I'll likely need an adapter plate to accommodate the BOP bellhousing unless the transmission has dual bolt patterns. What about the TV cable? Is there a way to hook that up to the LT1? And I assume the PCM will need to be flashed to remove transmission control. Can the PCM still do TCC lockup control?

 

[Fred Kiehl]

Did you ever think of getting a used trans (96 4L60E) to tide you over?

Are there any P-N-P junk yards near you?

 

[GoremanX]

I've had REALLY bad luck with used 4L60Es in the past. Once needed 3 of them before I found a good one, and the repeated R&R was a nightmare. The thought of doing that again fills me with dread. Plus I most likely need a new torque converter, too. I bet there's little bits of metal circulating through my transmission right now

 

[Marky Dissod]

LT1 pcms control the 4L60E's TCC, as part of the 4L60E.
If the PCM is not capable of controlling a 200-4R, not sure how it could control a 200-4R's TCC.

Remember - TC Clutch LockUp YOU Control

Here's the old thread @ web.archive.org ... Here's the first post ...Just finished a real simple mod that allows you to control your torque converter lockup clutch feature, with no Check Engine Light or apparent (PCM Comm) DTC's. Karl, Pat, and others, here's the deal: 3 Operating Modes...

www.impalassforum.com

Impala SS Forum: TC Clutch Lockup You Control

web.archive.org

Maybe this'll help?
Or, search TURBOWAGON231's posts?

TURBOWAGON231

www.impalassforum.com

EDIT:
You bought TURBOWAGON231's wagon, didn't you?

 

[jayoldschool]

You'd need the 93 F body LTI throttle bracket assembly for the TV cable, along with a converter lockup kit from a place like Bowtie Overdrives. And program the 4L60E out. Just thinking out loud. And a longer driveshaft, IIRC...

 

[sherlock9c1]

Personally, when I've seen 4L60E sunshell failures, the break is pretty clean. It doesn't put much of any metal in the trans. You can still drive it with 1 and 3, just use the manual shifter to hold 1st until you're moving fast enough to shift to D, then leave it in D.

You might just pull it out and put a new sunshell in it, and reassemble. You'll need a new pump gaskets, but that's it. If you were close to me, I could have it done in an hour once you put it on my workbench.

 

[GoremanX]

Interestingly, I've had no issues driving it in D all the time. It doesn't release 1st until 3rd kicks in. So it's basically like driving an oddly-geared powerglide with TCC lockup. If it wasn't for the lack of reverse, I wouldn't even care that much 🤣

I personally have zero experience working on any longitudinal automatic transmissions. But based on what you're saying, it sounds like I may not need a full rebuild... I wonder if I can find someone local who's willing to do just the bare necessity

 

[sherlock9c1]

You'll probably just have to sign some form saying you won't trash talk them when something else in the transmission breaks. That's what shops hate.

If I was you, there are tons of 4L60E teardown videos on youtube. Buy an old wooden chair from a thrift store like I do, use a 2" holesaw to make a hole for the tailshaft, and it'll be easy. You literally don't need any special tools to replace the sunshell. And you'll only have to pull the front planetary out, not even mess with the rear planetary and stuff.

and for your needs, a cheapo Taiwan-made reinforced sunshell will be fine.

Just sayin'.

 

[tayto]

why don't you swap it and let us know how it goes and if it's worth the time, money, etc? i'm also curious how you're going to recalibrate the 2004r to get similar part throttle and WOT shift points as the LT1/4L60E has.

 

[GoremanX]

That part isn't difficult. The stock 4L60 (basically a 700R4) on my '93 RMW with L05 V8 shifts pretty similarly to my '96 RMW. It's setup in the same way as a 200-4R would be. Other than the higher torque/HP beyond 2500rpm, the LT1 isn't that different. Honestly, because of the 3.23 rear end on my '93, it takes off quicker than the '96 does with its 2.93 rear. It just runs out of steam past 3000rpm. But for daily cruising, the differences are minimal and the transmission behaves pretty much the same. The only real difference is the gear hunting that happens on steep highway uphills, where the 4L60 will go back and forth between 3rd and OD and the 4L60E just holds OD, but that's mostly due to my L05 being very tired while the LT1 has almost no blow-by. A healthy L05 actually has more torque at that RPM range (+/- 2000) than a healthy LT1.

 

[Marky Dissod]

... why don't you swap it and let us know how it goes, and if it's worth the time, money, etc?
i'm also curious how you're going to recalibrate the 200-4R to get similar part throttle and WOT shift points as the LT1 / 4L60E has.

Unless a way to electronically control the 200-4R has recently been unveiled, the short answer is:
mechanically.
Hint: 3.42.

... because of the 3.23 on my '93, it takes off quicker than the '96 does with 2.93.
(The L05) just runs out of steam past 3000RpM.
But for daily cruising, the differences are minimal and the transmission behaves pretty much the same.
The only real difference is the gear hunting that happens on steep highway uphills.
Where the 700R4 will go back and forth between 3rd and OD and the 4L60E just holds OD.
That's mostly due to my L05 being very tired, while the LT1 has almost no blow-by.
A healthy L05 actually has more torque at that RpM range (+/- 2000) than a healthy LT1.

How many HEALTHY L05s are left? Even today, probably more healthy LT1s left than L05s.
Any well-maintained LT1, tuned for 91 octane, will have excellent throttle response and solid torque.

As for how the 4L60E behaves (as opposed to the 700R4), that is also very tunable.
And again, 3.42 would help both engines.

 

[GoremanX]

GM still sells brand new L05 short and long blocks. Those engines were used in so many pickups, vans and SUVs back in the day, commercial and consumer, that there's still demand to keep them running. I've been very tempted to acquire one and get my '93 back up to snuff, but I have more than enough projects as it is

 

[Marky Dissod]

GM still sells brand new L05 short and long blocks. Those engines were used in so many pickups, vans and SUVs back in the day, commercial and consumer, that there's still demand to keep them running.

From which an LT1 enthusiast might infer (for example) that, since GM stopped selling LT1s sometime in the 2000s, that there has been insufficient demand for new LT1s years since the 2000s.

I know GM also still sells brand new L31s too. At least L05s & L31s are both capable of 'highway mode'.

 

[GoremanX]

Oh there's no doubt it's unfortunate there are no new LT1 short blocks being manufactured. Honestly I think it's purely a volume thing, and the requirement to maintain that era's emissions in commercial vehicles. Personally I think the LT1 is the pinnacle of SBC design, and it's unfortunate that it's mostly been abandoned. They're disappearing quickly.

I ended up finding someone local who specializes in GM transmission rebuilds for a very reasonable price. He mostly rebuilds them for plow trucks and the like, though he does some oval track applications occasionally, too (which is how I heard of him). He's gonna do the complete removal, rebuild and re-install for $1500, using all brand new components, shift kit and torque converter. Seems worthwhile, and saves me from breaking my back R&R'ing the transmission. I dropped off my car to him this morning and he says he'll try to have it all done by the end of the coming week. Here's hoping!

 

[Marky Dissod]

Personally I think the LT1 is the pinnacle of SBC design, and it's unfortunate that it's mostly been abandoned.
They're disappearing quickly.

Except for the intake manifold (which was designed primarily to fit under an F-car's hood, with little thought about power UNDER 2500RpM, or how few LT1s would ever exceed 6400RpM), I agree completely, and hope that the ones that are left are well maintained.

... ended up finding someone local who specializes in GM transmission rebuilds for a very reasonable price. He mostly rebuilds them for plow trucks and the like, though he does some oval track applications occasionally, too (which is how I heard of him). He's gonna do the complete removal, rebuild and re-install for $1500, using all brand new components, shift kit and torque converter. Seems worthwhile, and saves me from breaking my back R&R'ing the transmission. I dropped off my car to him this morning and he says he'll try to have it all done by the end of the coming week. Here's hoping!

@sherlock9c1 will have better insight here than I will ...
Don't know if a 'shift kit' is necessary or helpful? Again, ask sherlock9c1.
Shifts should be pretty quick, and positive, but they should not thump, thud, or break the tires loose or anything like that.
In many cases, programming yields safer results than a shift kit - but maybe shift kits have improved over the years.

For $1500 ... good, fast, cheap, pick 2, something to that effect ...
If I could have a 4L60E rebuilt to withstand 6000RpM shifts in a 6000lb vehicle for $1500, I'd be willing to wait 3 weeks.
Hope his rebuild lasts you 5 years of fun driving (at LEAST).

 

[sherlock9c1]

If his expenses are low, $1500 is still doable for a quality 4L60E rebuild. There are corners you can cut on a stock LT1 application and still get a full life out of it. Shift kits - there are many ways to achieve quick shifts; buying a particular kit is only one way.

 

[GoremanX]

Car's back with its rebuilt transmission! Turned out better than I could've hoped. Shifts are smooth, and very quick without being harsh at higher engine loads. Noticeable improvement over pre-break. I've already got 300 issue-free miles on it, with a 2000 mile road trip coming up in a week.

Only issue... hood release cable broke 🙄

Still wish I'd gone with the 200-4R option, though...

 

[Caddylack]

The shop that built my trans can do a basic rebuild with warranty for $1400.

 

[GoremanX]

That's a pretty sweet price. This guy quoted me $1500 if I did my own R&R, and $1800 if he did the R&R. I was more than happy to let him do it for $300 extra. That was with a new torque converter. He also includes a 1yr warranty. But obviously that doesn't help me much if it breaks in Michigan next week.

The big transmission shop around here quoted me $2500 for a rebuild, plus $1000 R&R 🥴 And they had a 2 week lead time. Forget that crap.

 

[Caddylack]

That's a pretty sweet price. This guy quoted me $1500 if I did my own R&R, and $1800 if he did the R&R. I was more than happy to let him do it for $300 extra. That was with a new torque converter. He also includes a 1yr warranty. But obviously that doesn't help me much if it breaks in Michigan next week.

The big transmission shop around here quoted me $2500 for a rebuild, plus $1000 R&R 🥴 And they had a 2 week lead time. Forget that crap.

It's probably just a matter of competition/population.

R&R labor seems to be about 4 hours, and shop rates range from $75-$150 an hour.