E350 4R75E

Keith Browning · August 18, 2010

Fishing for opinions: A 2009 E350 with a 4R75E - The customer (2 employees from a local market) state that the transmission disengages at times while driving. Typically cruising down the highway and accelerating or climbing a hill. The RPM's climb and the van "loses power" or does not accelerate then catches.

I have no DTC's and cannot verify the concern, probably because I have the (VDR and a pressure gauge attached) but after not finding anything the first time the van came in the customer returning tells me that there has to be something going on. A discussion with other techs in my shop suggests that it is possible to have a problem with the forward or direct clutch developing, likely a seal. I removed the pan and found a bit of clutch material on the magnet - more than I would expect to see for 11,000 miles.

I have decided to pull the assembly and have a look. Anyone see this before?

cbriggs · August 19, 2010

You know, It almost sound like what I usually hear from customers when a fuel system or catalytic concern is developing. Step on it and trans downshifts, but truck lacks the ability to rev enough for that gear, and slows down, or "hesitates". I cant count how many times I've replaced fuel pumps or filters for " my trans wont shift up on a hill", or "my trans is slipping uphill". Might be worth a look? Have also seen maf sensors do the same sort of thing. Funny stuff happens whe the load calculation is skewed.

Keith Browning · August 19, 2010

Engine performance is always a consideration when diagnosing transmission concerns. In instances like the ones you mention customers will usually say the trans is slipping or shifts hard. This van runs great however.

Update: After pulling the pan and finding a gel mushroom on the magnet I decided to start digging and removed the main control, installed the test plate and performed the air leak check. Removed the trans and disassembled to find a burned clutch pack but no bad seals...

Mbl35 · August 19, 2010

Yea, in the short time i've been wrenching on diesels i've seen similar concerns on 7.3 caused by fuel restrictions. On 6.0 mostly cat or maf hose-split at the nipple on the intake not always setting a dtc right away and making it feel like a transmission concern.

Aaron · August 20, 2010

I have had two similar concerns, one on a gasser Econoline, one on a diesel F-series.

The gasser econoline FINALLY set a code during the concern...

P0297.... thank you sir, have a nice day.

And the F-series that was continually written up as a trans concern had a bad EGRTA sensor causing the truck to go into de-rate but not set codes or inform the driver.

Jim Warman · August 22, 2010

What clutch was burned? Did any valve body bolts come out "too easy"?

I like to take a straight edge and check the flatness of the worm trails. If you can do it with a warm trans, so much the better....

FWIW, my last victim, a 5R110 had a burned up forward clutch - over 1/2 inch of clutch pack clearance. I was surprised it would even move. This truck had extremely high pressure across the board. Pump and main regulator looked good. I couldn't cost cap it but there were no torque converters available and it got a reman.

Keith Browning · August 22, 2010

The direct clutch had a big air leak when I tested it but oddly enough the only clutch that was burnt was the reverse clutch. I checked the case where the output shaft goes, the shaft and the clutch assembly. I replaced the shell, the piston, the seals on the output shaft and the reverse clutch. It got a new valve body due to the goofiness of the condition and the resulting damage.