Highway RPMs seem high?
Hi there, first off my sig is my mods. Truck pulls fine around town and seems like the tranny isn't slipping.. I get on the highway, doing 100 km/h (60 mph I think?) my truck is seeing 2400 RPM consistently ! I can verify it is in O/D as it will go in and out and I have to pedal it to get it into O/D so I can do 100.. I have an A518, 3.54 gears as far as I know, and this seems obnoxiously high.. Any advice or anyone else seeing these kind of rpms?
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1:1 (3rd) ratio with your size tires you should be running 2169rpms at 100km/h.
.69 (OD for the a518) you should be turning 1496. Bad torque converter maybe? |
Something's off for sure. Getting on the pedal should kick it down to 3rd (1:1) not up into OD. :humm:
FWIW, I think you are due for a governor spring before you do anything else. |
Originally Posted by u2slow
(Post 1028627)
Something's off for sure. Getting on the pedal should kick it down to 3rd (1:1) not up into OD. :humm:
FWIW, I think you are due for a governor spring before you do anything else. |
I would say your tach is wrong.
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I'm pretty sure my tach is on.. Prior to my throttle rod and high idle shaft removed, it free idle to 2800 or so. The only thing I can think of is that either a) the TQ fins are bent/melted from PO causing a false higher stall speed, or b) the PO changed gears to 4:10s.
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Even with 4.10s your rpms should be about 1800.
You can check ratios using this calculator at the bottom of the page : Engine RPM Calculator |
My 92 at 55mph runs at about 1650-1700 RPM on a factory tach. 235/85R16 tires and 3.55 gears.
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Any sure fire way to check rpms besides another tach? I don't think it could be out almost 1000 rpm, but then again it does spin off the alternator..
---AutoMerged DoublePost--- Well, I changed the fluid, filter, adjusted the bands on the tranny and bumped the line pressure a bit and now it seems to run 2300 or so. There were very very few metal shavings in the pan, and the fluid was in tip-top shape. |
I can, your taking it off the alternator instead of the crank shaft. Gas car and a timing light is how I did it in the good ol days. Used the gasser for a reference and pointed the timing light at the diesel.
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