6.9 E350 C6 to E4OD or 4R100?

pivotro · Apr 19, 2026

I have an 86 E350 Cabriolet. The C6 needs to be rebuilt and the "factory" DNE2 overdrive has a melted limit switch for the shift motor. Would the E4OD or 4R100 be better to swap in? And what's a good site for buying the conversion kit?

IDIBRONCO · Apr 19, 2026

Either OD transmission will be better for highway use since they both have a lock up convertor which the C6 doesn't. They will cost quite a bit. I don't know if there's a conversion kit. You will have to buy a transmission and a stand alone controller and maybe other things that I don't know about. Bauman is one of the only stand alone controllers, maybe the only one. You might have to have driveshaft work done as well.

Nero · Apr 19, 2026

Usshift.com also makes stand alone controllers.

DirtyWood · Apr 20, 2026

Baumann & US Shift are the same company.

Nero · Apr 20, 2026

Oh heck, they do say that in fine print... Where are my glasses...... :smash:

nelstomlinson · Apr 20, 2026

I have a usshift controller on my vanbulance. It's way better than stock for understanding what's going on in the trans. Pretty happy with it.

SDEconVan · Apr 20, 2026

I converted to E4OD and upgraded the transmission to a 4R100 plus a few other goodies. BE SURE you get a DIESEL version of the E4OD or 4R! Also, DO NOT eliminate the bypass, you can encounter catastrophic failure. The torque converter must be custom made there's a place in Oregon that makes one that matches everything up and it is super low stall.

There's a lot more plus the Shift1/Baumann unit and proper gear selector unit.

But it's easier because I made a 40+ minute video on how I did it. I start the transmission build and conversion at 16 minutes into the video:

xc_hide_links_from_guests_guests_error_hide_media

BE SURE that you have all steel and 6-gear planetaries! The transmission that I first got was a diesel case but had CAR parts in it. Aluminum sprags and sun shell was weak garbage as well. I cover all that in the video.

Ask questions and save time and money!

BTW, that Cabriolet is sweet, a real unicorn of E-series! Convert to 4x4 and you'll have the unicorn of all unicorns!

pivotro · Apr 20, 2026

IDIBRONCO said:
Either OD transmission will be better for highway use since they both have a lock up convertor which the C6 doesn't. They will cost quite a bit. I don't know if there's a conversion kit. You will have to buy a transmission and a stand alone controller and maybe other things that I don't know about. Bauman is one of the only stand alone controllers, maybe the only one. You might have to have driveshaft work done as well.

I will mostly be highway driving, but I will eventually find and pull a camper with it. Does that make a difference in the one you recommend? The fact the splitter exists on this tells me I have to get the driveshaft resized. Which that brings up a question. The splitter has a yoke that bolts to the output shaft, and a slip yoke on the 2 piece drive shaft. Does the 4R100 have the same setup, or do I have to get a standard yoke that slides on the output shaft?

SDEconVan said:
I converted to E4OD and upgraded the transmission to a 4R100 plus a few other goodies. BE SURE you get a DIESEL version of the E4OD or 4R! Also, DO NOT eliminate the bypass, you can encounter catastrophic failure. The torque converter must be custom made there's a place in Oregon that makes one that matches everything up and it is super low stall.

There's a lot more plus the Shift1/Baumann unit and proper gear selector unit.

But it's easier because I made a 40+ minute video on how I did it. I start the transmission build and conversion at 16 minutes into the video:

xc_hide_links_from_guests_guests_error_hide_media

BE SURE that you have all steel and 6-gear planetaries! The transmission that I first got was a diesel case but had CAR parts in it. Aluminum sprags and sun shell was weak garbage as well. I cover all that in the video.

Ask questions and save time and money!

BTW, that Cabriolet is sweet, a real unicorn of E-series! Convert to 4x4 and you'll have the unicorn of all unicorns!

Is there a specific transmission model or year model or range to look for to get the 6 gear planetaries?

SDEconVan · Apr 20, 2026

The "good" models of E4OD will be late 80's into late 90's, diesel of course, trucks most likely. The gas ones from trucks with 460's aren't enough strength internally. Even if you change a gas case with the guts from a diesel 4R100 transmission, the case will not withstand the torque. It's the torque that will destroy the transmission. So build accordingly.

Look for the cut-away in the throat of the bellhousing and the extra gussets in the upper corners. They are unique to the diesel case.

Check that video at 16 minutes and 25 seconds, it shows what the proper transmission looks like.

Nero · Apr 21, 2026

Sure you arent thinking of the E4OD?

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SDEconVan · Apr 21, 2026

Thanks Nero, noted, and edited to E4OD. I used some upgrade parts from the 4R100, like the sun-shell and planetaries which are all forged, no aluminum. Also I should have mentioned that the torque converter will also need an input shaft from the same company. That way the E4OD diesel version will bolt right up to an idi 6.9 and most 7.3's

david85 · Apr 29, 2026

pivotro said:
Is there a specific transmission model or year model or range to look for to get the 6 gear planetaries?

6-pinion steel planetaries became an option on some E4OD/4R100 transmissions in 1997. Although, its such a common upgrade that it's relatively inexpensive to purchase them aftermarket for a rebuild. Cost of paying a shop to rebuild it will not be so cheap, however.

If you're using an all OEM transmission, look for a 1994 or older (or swap the solenoid pack from a pre-1995 into a later transmission). It would be far better to use an aftermarket controller/wiring harness, and find a later model transmission with most of the upgrades.

Unfortunately, you can never be sure of what's inside until you tear it down.

6.9 E350 C6 to E4OD or 4R100?

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