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E40D Transmission Rebuild Question

2K views 9 replies 6 participants last post by  8gitmusik1 
#1 ·
Hi all,

I've got a '94 E-350 Box Truck with the 7.3 IDI and E40D. Last year when pulling a grade with O/D off, my cooling system gave out and the engine of course heated up. I didn't let it hit the red zone (before I figured out the cooling system had given out), but it got close. Almost immediately afterward the transmission randomly downshifted on the freeway, O/D started flashing, and something slipped - from then on, at low speeds and gears, there is a metallic ringing sound when shifting, and it shifts very poorly. I since have installed a new all-aluminum radiator and the cooling system is solid, but as expected the transmission issues continued.

The strange thing is that when I pull the battery cables, let the truck sit for a bit and then connect everything back up, the truck drives and shifts fine for anywhere from 10-100 miles, and O/D light doesn't flash. Then, it will randomly slip again and start shifting like crap. This happens everytime I pull the batteries - drives fine at first, then goes down the tube.

I took the truck in and two different shops told me that there was internal failure in the transmission and I needed a rebuild ($2850!). I've got trust in these guys so I believe them. For my own edification though, I'm wondering why the vehicle would drive fine for a short while after reconnecting the batteries. I was feeling like it must have been a speed sensor or something prior to taking it in to the shop. Hoping someone can just educate me a bit on what might be going on.

Truck has 185,000 miles, and served as a U-Haul for the first 50,000 miles of life. I know these transmissions had some issues in the first place, and I'm sure its time as a U-Haul didn't help extend the life of the transmission any. I was expecting an impending rebuild at some point.
 
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#2 ·
I predict that your problem is a cracked torque converter clutch apply piston. That allows pressure that should be holding the clutch to leak past the clutch. This allows the clutch to slip. Once the slip exceeds 50 RPM for a certain amount of time (I've forgotten the time) it sets a slip code, flashes the OD light, and sets the transmission pressure high to try and protect the slipping clutch.

When you disconnect the batteries the code is cleared and the trans shifts normal. Once it recognizes the slip it sets the pressure high and the shifts bang.

The solution is a new torque converter. While the trans is out adding a rebuild is not that much more money.
 
#3 ·
Thanks for the reply Mark. So I'm assuming from your reply that a transmission rebuild like the one I'm currently receiving does not include the torque converter? I'm concerned now that they may not have correctly diagnosed the issue... or perhaps the transmission AND the torque converter are in need of repair?

The mechanic just called and told me that in addition to the transmission rebuild kit and everything for $2850, after opening everything up they discovered that two "hard parts" are also in need of replacement: a planetary gear something-or-other, and a solenoid pack (the solenoids cannot be obtained individually). Now I'm looking at $3,300. So painful...
 
#4 ·
If the rebuild doesn't include a new or rebuilt torque converter they are incompetent and ripping you off. I can't imagine rebuilding a transmission and reinstalling the old converter.

Finding damaged hard parts is not unusual, and normally can't be detected until the trans is torn down.
 
#6 ·
For $2850 rebuild, that should include everything that needs replaced, including the TC. You should replace the Aux cooler or add one if you don't have one. Tru-Cool is a good one.
 
#7 ·
cheaper option for coole ris wreaking yard, find a superduty power stroke that blew up (Shouldn't be hard) and pull the trans cooler, wash it out good, order a parker lfs trans filter, and there ya be.
 
#9 ·
Tranny Filter Tech | Trailer Life

The maximum transmission fluid flow rate is 2-6 gallons per minute in light trucks.

The Parker Racor LFS 22825 flows 8 gallons per minute and has a bypass valve which opens when the filter becomes clogged.

Another option is the Magnefine filter, which has a flow rate of 7 gallons per minute and has a bypass valve.

A third option is the BD Diesel Performance filter, which has a flow rate of 20 gallons per minute and has a bypass valve. If you buy this product, do not delete the transmission cooler bypass. Instead, rebuild the transmission cooler bypass valve if it is sticking. https://www.transmissionpartsusa.co...n_cooler_bypass_valve_kit_p/400-03660502k.htm
https://www.sonnax.com/parts/2078-cooler-bypass-valve-kit

Here are some sources.

Sources

Magnefine Boss Products USA Boss USA
Racor Parker Engine Mobile Original Equipment - Parker, 800-344-3286
BD Performance www.dieselperformance.com, 800-887-5030
 
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#10 ·
Tranny Filter Tech | Trailer Life



The maximum transmission fluid flow rate is 2-6 gallons per minute in light trucks.



The Parker Racor LFS 22825 flows 8 gallons per minute and has a bypass valve which opens when the filter becomes clogged.



Another option is the Magnefine filter, which has a flow rate of 7 gallons per minute and has a bypass valve.



A third option is the BD Diesel Performance filter, which has a flow rate of 20 gallons per minute and has a bypass valve. If you buy this product, do not delete the transmission cooler bypass. Instead, rebuild the transmission cooler bypass valve if it is sticking. https://www.transmissionpartsusa.co...n_cooler_bypass_valve_kit_p/400-03660502k.htm

https://www.sonnax.com/parts/2078-cooler-bypass-valve-kit



Here are some sources.



Sources



Magnefine Boss Products USA Boss USA

Racor Parker Engine Mobile Original Equipment - Parker, 800-344-3286

BD Performance www.dieselperformance.com, 800-887-5030
Great info. Im learning a great deal from your current and prior posts.

Thanks Don

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