Hey guys,

I've been searching have not yet been able to find a solid, straight forward answer for this questions. I have a 94 4L60E F-body transmission I bought as a level 3 from Performabuilt...for a different car. The trans was going in a 94 but that project is not happening anymore. I want to put it in my 97 WS6. I have been searching but have been unable to figure out exactly what all needs to happen to make it all work. If it makes a difference the car is also getting a 24x swap with an LS1 pcm (411). Your input is very welcome. Thanks.

Zach

 

That's a tricky one. The '94 and '95 are weird years for the 4l60e. I generally hear than those years aren't usable in other years but maybe there's some way to make it work.

 

You will NEED to swap the '95 Valve Body & plate for a '96-'08 version. And the internal harness if original...Technically you just need to swap the 3-2 Solenoid connector.

 

Cory is correct - the valve body and solenoids are quite different between a '94 and a '97. At a minimum you would have to update the valve body and the pump to convert a '94 into a '97. Otherwise the PCM will show codes and TCC lockup and the 3->2 downshift won't work properly.
Next, even a '97 will not bolt up directly to an LS engine.

Since you now have an LS engine, I strongly suggest you get a LS-style (300mm input shaft) 4L60E/4L65E from between '98 and '07. Avoid the LT-style (298mm input shaft) 4L60E as those don't bolt up directly to an LS engine. All '94-'97 4L60E are LT-style, but some later years are too. LS-style have a bolt hole in the 12 O'Clock position of the bell housing.

Note that you also need an LS-style torque converter.

 

Thanks for the info guys. The car still has and will keep the LT1...I am just going to run a 24x swap that runs with an LS1 411 pcm.

So what happens if you tell the pcm the transmission is a 94...would it not just act accordingly or would it still have the same issues? I feel like I remember Bryan Herter (PCMforless) saying that as long as you told the computer with year transmission it had that it would work just fine. It has been a while and I didn't want to waste my time if I was wrong.

 

You cannot tell the LS1 PCM what year 4L60E you have. It requires a '96 or later (up to '07) valve body.
If you are an expert 4L60E builder and have parts from other years, you could probably make it work, but otherwise the '94 will give you nothing but grief.

 

Yeah I'm starting to see that. I think I will just figure something else out. I'm not a transmission expert so I will have to change my plans. Thanks for the info though it definitely helps.

 

That is correct.....Forgot about the Pump.

There are many big power cars running 5 bellhousing bolts, 300mm input shafts aren't any stronger than 298mm shafts, The longer Stator Support may give marginally better Input Drum support....Though it didn't seem to help with rear Stator bushing wear. Stator Spline wear seems to be increased on 300mm units.
Crank spacers are cheap & the flexplate is easily re-drilled to the standard 10.75" spacing.

I have several customers with LT1 F-body & B-body cars running 298mm 4L60E's behind LS engines without issue with the correct components.

 

While a pro like Clinebarger can adapt a LT-style 4L60E to a LS engine, as can many reasonable competent home mechanics, there are plenty of threads here about people messing this up - putting an LS converter on a LT trans, installing the wrong flex plate, etc.
However the REAL issue here is that a '94 will require extensive rebuilding to work with a LS PCM.

 

The company that sells this particular kit (Torqhead LTD) says their gen 3 pcm WILL control a 94 and 95 transmission. I'm going to get some more info on it but as of last year they say they modify the computer to work with the earlier transmissions.

 

Understood, various aftermarket and custom PCMs/TCMs can control earlier transmissions, but often cost more than a run-the-mill 4L60E is worth.
Since you have a "built" '94 4L60E, a custom PCM might be worth it, but you might still find it cheaper or at least less hassle to find a newer trans.
For example, I regularly see even '06 and '07 4L60E/4L65E/4L70E on CL for $750 and these will work perfectly behind any LS engine (except C5 Vette) even those with an LS1 PCM.