Identifying GM Transfer Cases: Show us in pictures what you have with measurments and Adapters.

[RanchWelder]

My point in starting another thread on transfer case compatability, is because I'm in the process of adapting for my 87' Blazer to a modern electronic transmission with a stand alone and the 355HO TBI.

I own a 1998 LH 355HO with the crankshaft sensor, so I can possibly use the 0411 ECM, which is desogned to run the 4L80E, however, if you re-program the 4L80E and you do not run a stand alone controller, the ECM will refuse to adjust for the modified pressure system and fight the mods by attempting to force the line pressures back to what the General originally programmed. (Bummer).

The 0411 ECM can be reprogrammed. I'm not certain how much transmission programming can be done with the 0411.

So, I'm hoping there is a few Good Guys who have performed the OBD1 / 0411 mod and a few guys who have swapped over to an LH which can use the entire 0411 program, instead of just as a standalone. My OBD1 engine does not have cranksgaft or cam sensors. It would be great if the 0411 will run alone off the tach signal and a 5.7L / $L80E program.


Have read some guys say you can use the tach wire to run the OBD2 as a standalone for the 4L80E or the 4L60E.

If you know how this works, we can discuss this along with any great pictures or transfer cases, the adapters/Mounts, mods to cross members and measurements for driveline modification.

Hopefully, we get some great input from guys with experiance and whole bunch of data.

The first photo is the transmission ID tag for the 4L80E 4wd.
It will require the second VSS sensor be added, onto the third reverse drum during the rebuild, so signal to whichever stand alone unit I use, ie: the 0411 as a standalone or one of the aftermarket Transmission controllers can adjust off the 4o tooth gear.

Here is the 99" 4L80E to NP246 measurements. It is a driver's side drop and completely electronic. No shifters. Dash buttons.
I'm not able to use the driver's side drop.

If you know for certain which round pattern cases will match up, with correct spline count off the 4L80E, please chime in:

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Using 3-1/2" as center on the top bolt, I got 7" C to C.
Had trouble holding the camera with the wrong hand for the third picture.
Looking square down it was 7".

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Thickness of the Mount/Round Style Adaptor:

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Here's the pictures bucket.

My NP208 is on the truck now and it's been -35 for a week with a foot of snow.
If anyone can posts some measurement photos of the transfer cases they have laying around, maybe we can build a good refrence for adapting the 4L80E to an older Square Body on this forum?

 

[bucket]

Wow, that 246 adapter isn't very thick. I think the 241 adapter is thicker?

 

[squaredeal91]

I set out with a tape and my phone this morning to contribute to this a few things and my camera app isn't working?? 241 adapter is 3 1/2" thick

 

[RanchWelder]

It's warmed up to a modest 20-40 degree swing in temps every day for the next week.
I'll get under the truck and take some pictures of the NP208 to 700R4 in the next day or two, unless somebody beats me to it here.

I'm reasonably certain the 700R4 is 2-1/4" shorter than the 4L80E, and you can see how the mount between the transfer case can make a big difference with regard to drive line length.

 

[AuroraGirl]

My point in starting another thread on transfer case compatability, is because I'm in the process of adapting for my 87' Blazer to a modern electronic transmission with a stand alone and the 355HO TBI.

I own a 1998 LH 355HO with the crankshaft sensor, so I can possibly use the 0411 ECM, which is desogned to run the 4L80E, however, if you re-program the 4L80E and you do not run a stand alone controller, the ECM will refuse to adjust for the modified pressure system and fight the mods by attempting to force the line pressures back to what the General originally programmed. (Bummer).

The 0411 ECM can be reprogrammed. I'm not certain how much transmission programming can be done with the 0411.

So, I'm hoping there is a few Good Guys who have performed the OBD1 / 0411 mod and a few guys who have swapped over to an LH which can use the entire 0411 program, instead of just as a standalone. My OBD1 engine does not have cranksgaft or cam sensors. It would be great if the 0411 will run alone off the tach signal and a 5.7L / $L80E program.


Have read some guys say you can use the tach wire to run the OBD2 as a standalone for the 4L80E or the 4L60E.

If you know how this works, we can discuss this along with any great pictures or transfer cases, the adapters/Mounts, mods to cross members and measurements for driveline modification.

Hopefully, we get some great input from guys with experiance and whole bunch of data.

The first photo is the transmission ID tag for the 4L80E 4wd.
It will require the second VSS sensor be added, onto the third reverse drum during the rebuild, so signal to whichever stand alone unit I use, ie: the 0411 as a standalone or one of the aftermarket Transmission controllers can adjust off the 4o tooth gear.

Here is the 99" 4L80E to NP246 measurements. It is a driver's side drop and completely electronic. No shifters. Dash buttons.
I'm not able to use the driver's side drop.

If you know for certain which round pattern cases will match up, with correct spline count off the 4L80E, please chime in:

You must be registered for see images attach

Using 3-1/2" as center on the top bolt, I got 7" C to C.
Had trouble holding the camera with the wrong hand for the third picture.
Looking square down it was 7".

You must be registered for see images attach

You must be registered for see images attach

You must be registered for see images attach

Thickness of the Mount/Round Style Adaptor:

You must be registered for see images attach

Here's the pictures bucket.

My NP208 is on the truck now and it's been -35 for a week with a foot of snow.
If anyone can posts some measurement photos of the transfer cases they have laying around, maybe we can build a good refrence for adapting the 4L80E to an older Square Body on this forum?

The tach signal is coming off a gm hei like the 70s-80s or is it a later TBI HEI unit? Because the tach signal isnt going to be the same as a crank or cam singal, since those sensors use hall-effect sensors to determine the position of a toothed wheel or a similar. I think cam signal in later years was taken from the distributor mounted sensor but the crank would have to be at the crankshft. meaning a difrent balancer, a bracket, and a sensor

 

[RanchWelder]

$$$ opening the transmission and adding the second reluctor wheel is in my future.

 

[Blazerbiker]

We (Offroad Design) work on putting stuff on a 4L80 daily. 32 spline NP208 bolts right on to a 4wd 4L80. No mods required.

Figure 8 NP 205 requires an adapter housing (4" front to back) and a 32 spline input in the 205.

32 spline NP241 will bolt right on a 4wd 4L80 using the factory adapter. In fact, there were a few of them that were native behind the 4L80 in '91 subs and crews.

We can put a 40 tooth VSS on the NP205.
'90 and '91 241s came with VSS
NP208 requires a cable drive signal generator and a convertor box to get you to 40 pulses per revolution.

There's your conversion guide, for the most part.

 

[AuroraGirl]

We (Offroad Design) work on putting stuff on a 4L80 daily. 32 spline NP208 bolts right on to a 4wd 4L80. No mods required.

Figure 8 NP 205 requires an adapter housing (4" front to back) and a 32 spline input in the 205.

32 spline NP241 will bolt right on a 4wd 4L80 using the factory adapter. In fact, there were a few of them that were native behind the 4L80 in '91 subs and crews.

We can put a 40 tooth VSS on the NP205.
'90 and '91 241s came with VSS
NP208 requires a cable drive signal generator and a convertor box to get you to 40 pulses per revolution.

There's your conversion guide, for the most part.

https://www.offroaddesign.com/urethane-transfer-case-mount-for-gm-trucks-85-and-newer.html is this a really qualitr product? how long does it last? does it make the drivetrain too shakey?

 

[Bextreme04]

Yep, exactly what @Blazerbiker said. Any round pattern transfer case that was previously behind a TH400/4L80/late-SM465 will bolt right up to that 4l80. They will all have a 32-spline input. It gets more complicated when you start looking at Figure-8 stuff. I have a long 2wd output shaft on my 4l80 so that I can cut it down to the ~4-1/2" length it needs to be to mate up to the stock Figure 8 NP205 in my 1980 K25. I'm keeping the stock adapter and using an adapter plate to go from the TH400 index ring size of the adapter to the 4L80e adapter ring size.

You don't necessarily need 40 PPR, but it makes it simple so that you don't need to make changes in the ECM. You can make any changes you need in HPTuners(for ~$400) or you can use free software and cheap adapters to do the same thing. I have an OBDxPro VT tool and have used BlueCat to get my shift tables and pressures and Universal patcher or Tunerpro to make OS changes. You can read/write using PCMHammer or LSDroid.

If you have the 4x crank reluctor on that motor, then you can get cam and crank by using a Vortec distributor. Engine RPM comes direct from the 4x only though and the 1x cam sensor in the distributor is just used to know when to fire the fuel injectors. You can use the 0411 as a standalone by just putting the reluctor ring on carrier in the 4L80 and installing a sensor. Then make sure you have a switch that can tell the computer when it is 4lo. Then you will need to have the crank sensor connected(so you get RPM), a TPS sensor on the carb, and for best drivability you could use a stock air cleaner assembly with a MAF sensor piped in. This would allow the computer to make torque calculations so that it can properly control line pressure.

Honestly, if I was going to be putting the 0411 in anyways, I would just try and find a trashed or seized up L31 to get for dirt cheap and rob the distributor, coil, wiring harness, sensors, and fuel injection. Then you get the benefit of full fuel injection and a heavy duty overdrive trans all in one. Then you can use the same free software to do the VE tuning as well as tuning the trans so that it will all drive like a brand new truck.

 

[dragstews]

Just about finished with doing a 4L85E trans married to a NP203 ..

Had to get a "Johnny Cash" special 'a-dat-tor' plate ..

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That was the easy part of the install ..
Had to relocate the column shifter pivot ..

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Move the transfer case shifter ..

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Trans mount is seeing a spacer made up ...
Going from a TH 400 Oem 4x4 adapter to a 4L85 4x4 needed 4.6" more leg ..

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Using a slab of aluminum for a spacer ...

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A few mods are needed ...

 

[RanchWelder]

Cool.

What else?

 

[BearKing]

Just about finished with doing a 4L85E trans married to a NP203 ..

Had to get a "Johnny Cash" special 'a-dat-tor' plate ..

You must be registered for see images attach

That was the easy part of the install ..
Had to relocate the column shifter pivot ..

You must be registered for see images attach

Move the transfer case shifter ..

You must be registered for see images attach

Trans mount is seeing a spacer made up ...
Going from a TH 400 Oem 4x4 adapter to a 4L85 4x4 needed 4.6" more leg ..

You must be registered for see images attach

Using a slab of aluminum for a spacer ...

You must be registered for see images attach

A few mods are needed ...

Just curious as to why you are going with the 203 T Case and not a 205? Is it because it’s the factory Case?

 

[dragstews]

Just curious as to why you are going with the 203 T Case and not a 205?

I went though it with replacing the bearings, chain and converting to part time using a Mile Marker SS output shaft not long ago ..
The truck doesn't see very much 4x4 usage these days ..
Mostly only street use ...

You must be registered for see images attach

About the spacer that I was going to use on the 4L80 to the og K15 crossmember, I did a rethink on it and decided to use a after/market crossmember ..

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Wasn't plug & play fit, had to do a few mods to it in order to fit-up to what I had going on ..

After all was said and done, I'm very pleased with the install ..