Too low geared

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Nov 9, 2012 | 03:55 PM

Terry Durham

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Too low geared

Just going to throw this out there and see it any one has any ideas. I have a 1990 E-150 van with the straight 6(4.9) and a C6 trans and 3.55 rear gears. The problem is it feels very low geared. I have pulled the rear dif cover and the ring gear is stamped 3.55 so I know thats true. The trans will shift to 2nd and drive as it should but seems a little early. I have taken it to my local trans shop and they test drove it and said the trans is fine but didn't have any ideas. I also took it to a muffler shop as per trans shop suggestion and they checked the cats for pluging but said they were fine also. The tire size is right (265/75 15) for the van. The van runs great, has lots of power,will kick down to passing gear as it should and if you manualy shift it down to 2nd it down shifts also. Some of the rpms i'm turning are 2000 @ 45mph, 2600 @ 50mph, 3100 @ 60mph and as far as I can tell it should be doing about 2300 @ 60mph. In drive it should be one to one ratio and tran is not sliping so I kinda at a loss to what to do. Any ideas?

Nov 9, 2012 | 09:27 PM

95e150CW

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From: Outside of Memphis, TN

3100 would work out to around 70mph in your setup, due to an expected 10% or so torque converter loss. Your C6 doesnt have a lockup torque converter, so it wastes RPMs at cruise, converting them into heat.

Back up your speedometer readings with GPS or timing yourslef between mile markers. Make sure your speedo isnt lying to you (worn out perhaps). If everything turns out good, I would consider having a second shop check out the torque converter.

Nov 10, 2012 | 08:40 AM

SilverE350

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Considering that the van is an E150, I'm thinking the original tires would have been 235's. You now have 265's which are about 6% larger in diameter and are affecting your speedo reading accordingly.

Nov 10, 2012 | 10:13 AM

Terry Durham

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I looked again at the tires they are a 235 and that is what is on door tag. I bought this van in july and drove it 6 hours home at 65 mph and it didn't feel that low at that time. I know it felt a little low but nothing like this. This is another project so I dont drive it daily. It just feels like at about 45 mph it needs to shift again at the engine is starting to rev. At 60 engine is screaming. When we bought it the wife followed me home and at that time the speedo clocked right by the other truck. I have also changed the trans oil and filter, drained the convertor and the pan was clean. Still searching...

Nov 10, 2012 | 12:02 PM

Mark Kovalsky

Frmr Ford Trans Engr

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From: SE Florida

How many times does the transmission shift from a stop?

Nov 10, 2012 | 12:34 PM

Terry Durham

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When you take off it in low or first and I can do this manualy also, then shifts to 2nd then to drive. As I say I can move the selector arm manualy and feel it shift through the gears. If you take off slow it shifts to 2nd around 10 mph then to drive around 25 mph or so.

Nov 10, 2012 | 12:52 PM

Rick1025

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Is it shifting into Over Drive? The RPM's sound high for 3:55's. My 2002 w/ 3:55 is turning about 1700-1900 at 60-65 in OD.My old Dodge van w/4:10s did 3000 at 60 when not in OD.