Figured you IDI guys would be the best place to ask. But first, this is my first post, I self identify as a 1989 Centurion Four Door Bronco. I was built on a 4WD F350 chassis and have a 7.3 IDI and E4OD.

My transmission that at some point (I seam to have forgot when) was replaced with a Jasper unit is doing some oddball things. The most concerning of which is the RPMs sometimes flaring during the 2-3 shift. It hangs onto 2nd longer then I think it should then when making the shift to third the RPMs go up before it grabs. Once in third it's all good and pulls strong.

My new owner has been experimenting with fluid levels and replacing my fluid, which I'm sad to say has been neglected. It's quite dark, though doesn't smell burnt. We think things are better with the fluid level a little low having noticed some bubbles on the dipstick when high(in hash mark) and figuring my fluid was foaming. We've also noticed that it only does the flare after I've been on the road a while. This likely fits the high fluid/foam theory though time will tell.

My new owner bless his heart is intent on ordering a Baumann controller as soon as they open Tuesday morning. We hope this along with more new fluid and likely filter service will get my transmission feeling closer to 100%.

The question I ask you all is will it or should we be planning on a transmission transplant in the near future. I'd hate to have to endure that and put my new owner through all that stress. But what could be causing that 2-3 flare?

We'd also like to find anyone here who has the Baumann controller, any tips they have etc.

I'm sure we'll know more soon, with more fluid being swapped out and hopefully soon the new controller. But I'd really like to get some opinions on the late shift and flare?

 

Have you done a complete fluid swap? Also, unless the pan is leaking I would leave it and the filter alone since they are very course and don't really clog up.

For the complete fluid swap pull the hose coming off the cooler that goes back to the trans and put it in a bucket. Start the truck up and start dumping in new/clean ATF as the old stuff pumps out. Have a helper run it through all the different gears while you do this to make sure you get all the old fluid out. Keep an eye on the fluid coming out into the bucket since the pump will pump it out a little faster than you can dump it in. On my c6 I have to turn the vehicle off for a little bit in the middle of the swap so I can catch up. There are quite a few Youtube videos showing this process as well as a tutorial that was typed up here on the forum.

As far as the Baumann controller, I have looked in to them since at some point I may swap out my c6 for a built e4od. All the reviews and feedback I have read on them is that they are great. I also contacted them with some questions and received very quick and thorough responses.

 

Here is the complete procedure to change the fluid. https://www.ford-trucks.com/articles...-transmission/

 

I ordered the controller it will be here next week. I've also purchased for good measure a new FIPL sensor/TPS and a new MLPS. I'll install those this weekend.

My MLPS seems fine except the connector to it is broken and it looks like it's been on there 100 years. The new one came with a new connector and the controller harness will have it's own connector. I'll replace the MLPS for good measure, and put the new connector on the old harness. This will give me a fresh MLPS, a spare old MLPS, and a good stock wiring harness should I need to go back to the factory controller.

The TPS/FIPL sensor I'm concerned about. While I'm not sure on how it's testing, the issue appears throttle dependent and intermittent. So I'm going to replace that sucker. Also got a new connector for it so again I'll retain the original harness and use the new connector on the Baumann harness.

Fluid, I kinda do what you two described only different. I've T'd into the transmission cooler line and placed a valve on the leg with a length of hose. Placing the valve on the inside of the right fender. This way I can let it pump out fluid into a container, use the valve to control flow, and do it while also able to put in fluid. I've been pretty much doing a couple courts a day for a while now. While I don't think complete fluid changes do harm, I also see no harm in a slower swap. If anything it's slightly better as half the point is a flush and might as well not shock the thing. Well that and it's easier, I do it on my lunch break, lol.

I'm leaning towards also doing the same kind of thing with the VSS, but I think I have a spare one of those and connector. As well as adding an in-line oil filter. The stock one being so course, be nice to filter it better.

 

No, it's not slightly better. It's a lot worse. You are doing a lot of mixing of old and new fluid and then changing a little of the mixed fluid. If you followed the procedure I quoted you would mix very little and change just the old fluid.

And shocking the transmission with new fluid is just an internet myth. It doesn't exist.

 

To my mind it depends on what's bad about he old fluid. My fluid isn't burnt it's "dirty", it's dark but has no burnt smell. So the materials contaminating the fluid are also throughout the transmission. After a swap to new fluid it would quickly become dark again with contaminants. By allowing it to mix I'm also allowing the new fluid to pick up contaminants, mix with the old, and then I'm taking it out. I may ultimately use more fluid this way but I end up with a cleaner tranny.

Frankly it's more of a reason to install a filter then anything else but I don't have a filter yet to install and am still looking into it. Any suggestions there?