95 4L80e from a Diesel truck, anyone know what has to be changed other that the torque converter to go behind a gas engine?

[PedroC]

I got a 4L80e for cheep from a friend but it off a parted out diesel truck looking for info.
Is the main pump the same? The guts should be exactly the same but I don’t know and it’s hard to find anything info other then the torque converter is different.

 

[stutaeng]

I'm not sure on the torque converter... I "think" there was just one type? B81 or something like that?

AFAIK, there are no differences in the gas vs diesel internal components of these units (or SBC vs BBC for that matter.) Differences were more related to years though.

What year is your truck?

 

[Schurkey]

First Guess: Just like all the other GM automatics, there were multiple versions each year, tailored to the vehicle it was installed in. Some would use more or fewer clutches in the various clutch-packs; different sized pistons in the servo(s), and in the days before computer control, there'd be a bunch of changes to valve body, governor, modulator, etc.

However, I bet that ANY 4L80E has enough strength for the majority of folks. With computer-control of shifting and pressure-regulation, the valve body/governor/modulator differences would not apply.

If there's something diesel-specific about that trans that would make it unsuitable for a gasoline application...I don't know about it.

 

[tpass]

as a general rule.. 91-93 can be interchanged.. and 94+ can interchange. If you try to put earlier into later there are some mods that need to be done, but I don't know what they are. (TCM related)

Quick way to I.D. them is the 91-93's have the cooler lines right next to each other. The later versions have cooler lines spaced much further apart, one is more rearward.

 

[stutaeng]

as a general rule.. 91-93 can be interchanged.. and 94+ can interchange. If you try to put earlier into later there are some mods that need to be done, but I don't know what they are. (TCM related)

Quick way to I.D. them is the 91-93's have the cooler lines right next to each other. The later versions have cooler lines spaced much further apart, one is more rearward.

Agreed on the 91-93, and 94+. I've never seen them, but some of the early ones (91-93?) had a bolt-on case connector, or so I've read.

The 91-96 units had the cooler lines side by side. It was in 97 that they introduced the rear lube circuit.

I've got a unit with a '94 tag on that I rebuilt (guy say it came from a 95 C2500 truck)...sometimes the year of the unit can be a year lagging the year of the truck, I imagine on the time the transmission was built at the factory vs what truck model it actually makes into?

 

[tayto]

the early units had a different case connector. most have probably been updated at this stage. using a 91-93 unit in 94+ is fairly straight forward. the big thing that needs to be replaced is the PCS. you will need to drill a vent in the valve body for this solenoid as well as use an update separator plate (transgo). i think ypu can block a hole in the old separator plate, but i have never done it personally. you can also use the 94+ accumulator housing as well. GM deleted the TS compensator valve in the 94+ units. , i have discarded and blocked it with set screws and epoxy if the budget does not allow getting the updated one.

not to sure why the diesel converter wont work pretty sure it's the same bolt pattern as a gaser. however, it will have a lower than normal stall speed.

 

[Supercharged111]

As far as I know, there are 2 torque converters: loose and tight. Tight = 454/6.5, loose = 350 and anything less (think bread trucks). I think they were B81 tight and B82 loose.

 

[MIHELA]

There are 3 stall speeds; low, medium and high. Diesels are low stall, rated somewhere around 1600 RPM in a stock engine application.

 

[Supercharged111]

There are 3 stall speeds; low, medium and high. Diesels are low stall, rated somewhere around 1600 RPM in a stock engine application.

Can you break that down further? When I rebuilt the 97 4L80 for my 98 K1500 there were only 2 converters in the book, and my dually stalls around 1600. Maybe there was a year break?

 

[MIHELA]

99+ introduced the high stall behind the 6.0. It's around 2200 stall. Diesels and some 350s got low stall. Medium stall was like 4.3s and some 350s, 1800 rpm stall.