My87Landmark
Registered User
I've come to grips running at 3,000RPM's at 60-65mph. But at ANY SPEED when I let off the gas it IMMEDIATELY SLOWS. Is that normal ????
1987 E-350 W/ 6.9 Deisel / C6 3spd auto
- Thread starter My87Landmark
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WrenchWhore
Full Access Member
I mean yeah when you take your foot out of it it will slow down. Unless you mean it's doing this aggressively like the brakes are dragging?
CarterDawson
Registered User
Yep normal deceleration!
He is used to vehicles with overdrive, where when you let off the pedal they tend to keep going by themselves. Take any of your newer vehicles and pull them out of overdrive, and they will act the same way as your van when you let off the throttle.
It's a lot of work, but swapping in a overdrive transmission is great. It's hard to justify it with your fuel savings, I got 3 more mpg when I did it, but even with that it would take years of driving to come out even on the cost. But being able to keep up with modern traffic, being able to hold a normal conversation with a passenger because of the less noise, and just the idea of less rpms so less engine wear justified it for me. Plus I bought a donor truck for the overdrive transmission, and was able to sell parts off of it to recoup some of the cost. Overdrive is a wonderful thing.
It's a lot of work, but swapping in a overdrive transmission is great. It's hard to justify it with your fuel savings, I got 3 more mpg when I did it, but even with that it would take years of driving to come out even on the cost. But being able to keep up with modern traffic, being able to hold a normal conversation with a passenger because of the less noise, and just the idea of less rpms so less engine wear justified it for me. Plus I bought a donor truck for the overdrive transmission, and was able to sell parts off of it to recoup some of the cost. Overdrive is a wonderful thing.
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PhilBilly3477
Registered User
Yes. Normal. Very high compression engine. 
And an absolute benefit to my old man style driving. Really helps save on brake pads too.
And an absolute benefit to my old man style driving. Really helps save on brake pads too.
For the noise and engine speed part, I can't hear in any IDI I've ever rode in. I've had a zf5 with 3.55s and a 6.9 c6 with 4.10s, either way talking to others or listening to the radio is pretty much impossible. You need sound deadening foam bs in the firewall and floorboards under the carpet. Everything else I agree with obviously, just wanted to mention that part.
My 88 was nicknamed
Disturbing the Peace.
The 93 whistles like a New York construction worker.
But at 80 I can talk to the better half.
Disturbing the Peace.
The 93 whistles like a New York construction worker.
But at 80 I can talk to the better half.
My87Landmark
Registered User
Hey everyone THANK YOU ALL for your knowledge. Now it all it makes sense.
My87Landmark
Registered User
Am I gonna have to swap out the rear end also ??? What year tranny with O/D did u put in ??? My rear end is a 410.i suppose that doesn't help much
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I swapped in a ZF 5 speed. You need the 4.10 for towing. You can have your cake and eat it too by leaving the 4.10 rearend, you can tow and not be in overdrive, and use the overdrive for running empty.
I swapped the zf in because it was the cheaper factory option. The other factory option is the E4OD automatic. It will bolt in with a little driveshaft work, but you will need a aftermarket controller to shift it, it's a electronic transmission. And you will need the actual shifter also. Being electronic, it needs the controller which used to be a little more than $500, but has probably gone up by now. But with the controller you get some neat features the newer trucks have, like tow haul modes.
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