Why is my truck so slow?
#1
Why is my truck so slow?
1990 F150 5.0 zf5spd 4x4. When I have my foot to the floor, I can get passed by a school bus. Here's all the work I've had done by a shop (so I know it isnt the problem)
-New transmission seals and shift forks
-Head gasket
-valve job
-machine heads
-cleaning of all disassembled engine parts
-new jasper rear end
-sway bar, ball joints, tires
-all fluids correct levels
So, I think it might be an incorrect gearing between the front and rear axles. The front end was "rebuilt" before I bought the truck. I think it may be a different gear ratio than the jasper rear. Any ideas?
-New transmission seals and shift forks
-Head gasket
-valve job
-machine heads
-cleaning of all disassembled engine parts
-new jasper rear end
-sway bar, ball joints, tires
-all fluids correct levels
So, I think it might be an incorrect gearing between the front and rear axles. The front end was "rebuilt" before I bought the truck. I think it may be a different gear ratio than the jasper rear. Any ideas?
#2
1990 F150 5.0 zf5spd 4x4. When I have my foot to the floor, I can get passed by a school bus. Here's all the work I've had done by a shop (so I know it isnt the problem)
-New transmission seals and shift forks
-Head gasket
-valve job
-machine heads
-cleaning of all disassembled engine parts
-new jasper rear end
-sway bar, ball joints, tires
-all fluids correct levels
So, I think it might be an incorrect gearing between the front and rear axles. The front end was "rebuilt" before I bought the truck. I think it may be a different gear ratio than the jasper rear. Any ideas?
-New transmission seals and shift forks
-Head gasket
-valve job
-machine heads
-cleaning of all disassembled engine parts
-new jasper rear end
-sway bar, ball joints, tires
-all fluids correct levels
So, I think it might be an incorrect gearing between the front and rear axles. The front end was "rebuilt" before I bought the truck. I think it may be a different gear ratio than the jasper rear. Any ideas?
#4
#6
Jump, turn into scrap steel ( fork in a blender comes to mind) all things that would happen, yes. But in 2wd it would have zero effect on the drive line. Did you match the jasper to the door jam info?
#7
If things aren't too rusty just loosen the studs at the manifolds to produce a pretty good leak, or take the pipes completely off the manifolds IF you can get the nuts off the studs with out too much trouble.. Don't forget to use plenty of PB blaster/ or your favorite penetrating oil. if things are really rusty start spraying a day or two in advance. Then drive it and see if there is any change..
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#8
My son and i swapped the Mazda 5-spd in his 92, for a ZF trans...noticed the gearing difference right away...i was told the ZF is more of a heavy truck trans,thus geared lower and slower...made to haul a load...not haul a**...
That said, if it's only noticeable in 4x4, your diffs don't match, as others have said.
That said, if it's only noticeable in 4x4, your diffs don't match, as others have said.
#10
you need to do a few things here. first figure out what gears you have out back and in front. I wouldnt use 4wd until you confirm they are close.
What size tires are you running? also you shouldnt be using first gear unless your wanting to CRAWL. first is a granny low gear similar to the old NP435 4speed trannies. and like mentioned this is a HD tranny geared lower then the m5od you previously had.
#13