4l60e had uh-oh in a 96... recommendations?

[stutaeng]

I think the electronic version started later than that...look here for design changes:

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[Nad_Yvalhosert]

GMT400 Vortec OBD2 is 96-98 in the pickup, 'till 99 in the SUV, and '00 in the Escalade/Denali.
I dont know about the GMT800 series interchange. Someone else can respond?

 

[Schurkey]

You cram in a TH350, you're in for a nightmare of kludgework getting vacuum plumbing, and kickdown cable working. You'll probably give up the lockup torque converter (There are some TH350C transmissions with a converter clutch) and you'll absolutely give up fuel economy and have increased engine wear due to the lack of overdrive.

The ECM will be expecting to control the transmission: shift points, manage the line pressure, etc. So expect the MIL light to be constantly on. Depending on computer programming, this might also put the engine into some sort of "Limp-Home" mode because the computer thinks the transmission is cooked. I don't really know, and I have no interest in finding out.

Get a Treasure-Yard 4L60E suitable for your truck, with a warranty from the seller, in writing. 2WD transmissions aren't so hard to install. (4WD makes it a whole lot more awkward for a D-I-Y installation.) FLUSH YOUR TRANS COOLER(S), or just replace it/them, then FLUSH THE FLUID in the "new" trans, and install a fresh trans filter.

Here's how this works: Tell Dad that he overloaded and abused the truck, so he can kick in half (or more) of the cost of fixing it. Dad has significant responsibility here, even if you own the thing.

And tell him to stop deliberately damaging the truck with "fixes" like he did with the hole in the floor. (First thing I think of when I hear about failed shift cables, is that the shift cable maybe became a ground-strap and welded itself to the sheath. A failed engine/trans ground strap can kill a shift cable in short order.)

Yes, a 1500 almost certainly has a 10-bolt, 8.5" ring gear axle with shiity leading/trailing shoe brakes of only 254mm (10 inch) diameter. So "2000 pounds" in the bed all the time is not wise.

 

[Nad_Yvalhosert]

no. this pic is my 1980 gmc 350. the 96 has a vortect with tbi. I presume tbi at least, not likely port i dont think

But the info by nad is helpful, thanks. Well, the th350 wouldnt need a tv cable but the kickdown which would be easier to fab I would think than a TV cable. I dont have any lines on a 700r4 nor do I want to mess with a TV cable lol.I might consider using an engne and trans for trade or to cut price if we can find something decent or someone who needs something themselves. But based on the special intake and such, I dont feel like dropping a 305/350 with unknown wear, v belts, and then a 3 speed in and take the obd2 engine out, at that point I would be just better getting a engine less chassis because this trck aint perfect and i would be making more work trying to avoid work haha!

On the subject of transmissions then, what are years of 4l60 that could be replacement transmissions? 91+ would be electronic but im sure sensors or internal changes happened that make cutoffs like the 4t65e in my buicks case.(1997-2002 being its range without massive work)

On the TH350, the kickdown cable IS the TV cable. It's two names for the same thing: Throttle Valve
It's the TH400 that doesn't have one. Just a vacuum line to the modulator.

Also, the Vortec IS port injection. Its known as a CPI, or Central Port Injection. The butterfly assy on the top of the intake is a dry Throttle Body. Not a TBI. TBI is Throttle Body Injection. The TBI combines fuel injectors AND the butterfly opening.
For sake of conversation, the Vortec 454 is SFI: Sequential port Fuel Injection...

 

[Schurkey]

On the TH350, the kickdown cable IS the TV cable. It's two names for the same thing: Throttle Valve
It's the TH400 that doesn't have one. Just a vacuum line to the modulator.

Not exactly.

A TH700, or 4L60, has a Throttle Valve (TV) cable. If that cable isn't connected properly, or the throttle valve in the transmission valve body that it controls sticks in it's bore, the transmission burns up in short order, OR (much less common) the shifts are unreasonably harsh until the trans fails. The TV cable and throttle valve have a major impact on transmission line pressure and shift quality. The '700 and 4L60 does not use a vacuum modulator because the TV cable and throttle valve handle line pressure changes according to engine load (throttle position.)

A TH350 has a Kickdown cable. You leave it disconnected, the trans kickdown doesn't work, but the rest of the trans survives nicely. The kickdown cable controls...kickdown. The vacuum modulator controls the line pressure based on engine load (manifold vacuum.)

A complicating factor is that the geometry of the throttle lever and cable pivot is slightly different between what's intended to work with a TH700/4L60 TV cable, and what's intended to work with a TH350 kickdown cable. A mistake on GM's part, I think. You swap a TH700 or 4L60 into a vehicle that used to have a TH350--or the other way around--and the TV / Kickdown cable geometry isn't correct.

And the kickdown on the TH400 is via an electric solenoid controlled by a switch somewhere on the throttle linkage. Early vehicles tend to have the switch near the carburetor, later vehicles tend to have the switch at the gas pedal. Either way, electrical power engages the solenoid, which causes kickdown. Like the TH350, the line pressure vs. engine load is controlled by the vacuum modulator.





Lastly, a correction or at least an addition to my earlier post. The shift cable can become a "ground strap", and they will sometimes weld themselves to the cable sheath leading to binding-up and eventual seizing of the cable. It's not the engine/trans ground that failed, it's the body ground--instead, the body grounds TO the transmission via the shift cable, which grounds to the engine, which grounds to the battery via the bigass main battery negative cable. I was thinking backwards, somehow.

 

[yevgenievich]

Ecu will complain, but will run the engine fine. Speedo will not work. For a beater truck that needs to move around th350 would be ok. And as above on modulator. Kickdown cable can also just run in to the cab. Pull the cable when need to downshift....

But fixing 4l60e is better.