converter change
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Freshman User
Joined: May 2009
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converter change
my stock 99' f350 diesel torque converter started rattling bad recently with 174000 miles . It was fine in lockup mode but rattled badly the rest of the time. So I replaced it with a CVC (consolidated vehicle converters) converter (part # WFM64PHD) this is a 3 clutch disc , billet cover style that was supposed to be the same stall as my factory one... Now heres the problem , I have owned this truck for 6 years and drive it daily , so I know the rpms it runs at . And the new converter runs about 400 rpms faster (in lockup mode ) than the old one.... I know its in lockup because I can push the overdrive button off and it revs up , or I can gently push down on the brake pedal when driving and it will jump right out of lockup ... My gas mileage is gonna go to the toilet , but how can this be , I thought lockup was lockup 1 to 1 ratio ??? Whats going on here ???? Right now heres what its spinning
55mph = 1750rpm
60mph = 1900
65mph = 2050
70mph = 2250 rpms
before 70 mph was right at 1850 because if I saw a hill coming i always had to get a run so that my tach was at least 2000 rpms to get it powered easily up the grade without a bunch of downshifting , so I know something is amiss . HELP ????
55mph = 1750rpm
60mph = 1900
65mph = 2050
70mph = 2250 rpms
before 70 mph was right at 1850 because if I saw a hill coming i always had to get a run so that my tach was at least 2000 rpms to get it powered easily up the grade without a bunch of downshifting , so I know something is amiss . HELP ????
Frmr Ford Trans Engr
Joined: Aug 1999
Posts: 24,738
Likes: 2,666
From: SE Florida
If it is locked it can't be at a different RPM. That's impossible. It seems that it is not locked when it used to be locked. Pressing the OD OFF button will not unlock the converter, it will make the trans shift from 4th to 3rd.
More Turbo
Joined: Aug 2002
Posts: 537
Likes: 17
From: Linden USA
Did you also have the trans rebuilt at the same time? If the converter is truly locked than your RPM's should be the same, if everything else is the same. If not, it is not locked and is slipping.
Post Fiend
Joined: May 2006
Posts: 10,007
Likes: 4
From: Central Florida
If it is running faster which would mean that the crank shaft is not locked to the trans input shaft, then you should see the fluid running hotter. The slipping in the lock up disc will burn the fluid up, so watch your trans temps.
New parts don't mean good parts, every manufacture will produce a few bad apples. The lock up doesn't make the ratio 1:1, but it does make the crankshaft and input shaft speeds equal, OD is still going to be 0.74(or 0.71):1 from the engine to driveshaft.
New parts don't mean good parts, every manufacture will produce a few bad apples. The lock up doesn't make the ratio 1:1, but it does make the crankshaft and input shaft speeds equal, OD is still going to be 0.74(or 0.71):1 from the engine to driveshaft.
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Freshman User
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it is definately running alot harder , although it is not running hotter , the trans tenp is now only running about 160-170 ..... and I didn't have any tranny work done , just the converter swap , A mechanic told me that while driving down the road if i keep the accelerator at a steady speed such as 60 mph , and reach down with the other foot and gently push the brake , it will drop out of lockup and raise rpms about 400 rpms. It does that , is this correct ? Chasing my tail here , have gotten about 14 mpg for 5 yrs , this last tank just over 10 !!!!!!
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Tuned
Joined: Dec 2007
Posts: 311
Likes: 7
From: East TN
I had a Precision TC put in my truck about a year ago and noticed a higher rpm shift point so i think the new one had a higher stall speed than the stock one?
Check this out.......its got a lot of good information on how the convertor works....
http://www.tciauto.com/Products/Tech..._explained.asp
read especially at the bottom "drivablilty concerns"
Check this out.......its got a lot of good information on how the convertor works....
http://www.tciauto.com/Products/Tech..._explained.asp
read especially at the bottom "drivablilty concerns"
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