4L80 questions

Since you’re just about completely rebuilding it to bring it back to a regular driver, you might as well build another one to replace it and if you don’t need the one that’s in there, sell it to recoup some money spent.

I'm also new to modern tech but have fried multiple ODs and researched the 4L6** extensively, hoping to drop one into a G Body. It's close enough for conversation. Does it actually have a manual VB or did someone just hook up a $50 eBay controller and call it manual? I've looked into those and even the "good" ones fry the trans in short fashion. Wiring the solenoids to the shifter positions or even SPST switches gives full manual but saves the trans. The torque converter would need the same for lockup functionality. A standalone like a U.S. Shift Quick 4 would solve those issues easily but don't bother with an Aces Quick Draw- lack of correspondence. I've had my eye on a Quick 4 for sale on another forum recently, maybe it's still available:

On a performance trans if it needs a different VB then I'd be concerned that the pressure settings and various valves & mods inside are necessary for the longevity of the other parts and mods- VBs are extremely complicated. The clearances, separator plate, accumulators, and servos all need to be copacetic with the VB and its many fluid paths, if you change that it might not be happy. Clutch/ band clearances not matching the orifice size in the separator plate could result in dragging clutches or simultaneously engaging two forward gears- this is a game of thousandths, though it takes a few. Same goes for clutch apply pressure, speed, and clutch material. If fluid paths were modified to eliminate an accumulator or redirect fluid to initiate an act in a different way then you're immediately in trouble. I'd hope that a competent specialist could recreate the mods in another VB given that they're conducive to full auto control.

In researching various mods done by reputable performance shops and even a GM hydraulic engineer I discovered that there's about 1k ways to mess one up. I'd hate to kill a good one by mismatching parts.

If it's not a "built" trans then perhaps the VB could be swapped without issue, and a standalone controller or switches will get you rolling. I'd still be leary of swapping VBs as there were various changes to the 4L6** over the years that "don't matter" until they do, like in custom applications. I can't say for sure if the same is true for the '80.

Holley forums turned up this:

Is it a 4L80 or a 4L80E? If it's a 4L80, more than likely you can just install an original valve body. If it's a 4L80E, you'll need some sort of controller. If you can get the car at the right price, it can be a good deal, but use the transmission as a bargaining tool. It seems strange that someone would install a manual valve body in a cruiser. There's a good possibility that there's something wrong with the transmission.

As said the valve body will probably need changed, depending on how the manual conversion was done. Probably best to get the Sniper TCM to control it with the same 3.5" handheld. While I have been less than thrilled with the Terminator X Max on my Olds 350 SEFI conversion, the trans control works quite well. I did have to adjust the 3 to 4 shift to happen later under light throttle. Very normal shifts with their tables. I am installing the Transgo 4L80E HD2 shift kit this weekend to add even more durability to this trans.

Ribbedroof said:

Looks like a moot point, guy won't respond despite having it listed for sale and having read the messages I sent.

Back to the drawing board I guess

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Take that as a good sign. Wait until the right car comes along. They always do.

A full manual valve body with no TPS input for EPC solenoid is not going to be friendly to street drive. But if the line pressure is being controlled via the throttle pedal, and the rest of the trans is mostly stock, then a manual valve body is not awful to use if you have a decent shifter. And consider that you really don't need 1st gear unless starting on a hill or are heavy as heck, then starting in 2nd gear is a good thing.

Converting back to full auto will cost more than finding a good donor and putting a stock rebuild on it IMHO.

The salient point here is the pedigree of the box. Is it a 4L60 as described, or the "E" variant? Both the L60 and its heavier brother, the L80, come factory standard with no electronic controls. Having that "E" in the descriptor means that either one would need some kind of controller or CPU to function correctly.

Essentially they are both built on the heritage of the TH350 chassis and the TH400 chassis. When GM went four speed, you then got the 200R4/700R4, both, externally, almost identical to the earlier cases. The difference is almost completely internal and it is the OD gear plus the use of internal ATF pressure and the TVS cable that serve to direct the shifts, as opposed to the earlier boxes which used a vacuum actuated module. that significantly differentiates the two generations.

The 700, in turn, evolved over time to become the basis for the 4L series.

Do be aware that the late 4L case does not bolt directly to a Gen I engine block, and might not directly bolt to a Vortec block either; similarly the 200R4/700R4 will not bolt directly to an LS. Just as a personal note here, for me to mate my 200R4 to my "Orphan LS" 5.3 motor, I will need to purchase an adaptor kit from Speedway. It is all about the number and location of the bosses for the bellhousing bolts on the block versus those on the t-case, and the block has one less boss and likely uses metric capscrews. I have come across comments that noted the possibility of drilling the missing hole as they claimed that the boss did exist, only un-machined. The big maybe in all that was the alleged proximity of an adjacent oil or water passage that the drilling could perforate and result in problems.

Ya pays yer money, and ya takes yer chances.


Nick

86 Salon said:

Is it a 4L80 or a 4L80E? If it's a 4L80, more than likely you can just install an original valve body.

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CopperNick said:

The salient point here is the pedigree of the box. Is it a 4L60 as described, or the "E" variant? Both the L60 and its heavier brother, the L80, come factory standard with no electronic controls.

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There was no 4L80......just the 4L80E introduced in 91.