Changing rear end ratios
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From: Sweden
Changing rear end ratios
What is the procedure for changing rear end ratios in an '87 E150? I've been told I can get better performance on the highway with a better ratio. It does kinda peak out at 65-70 mph or so on level ground, and the engine rpms seem pretty low for being at top speed. There's notable pickup at highway speeds if I shift into second but of course then it's revving too high. It'd like to be able to do this myself especially since it may not work out and I'd have to undo the job.
I've had the diff apart before to change the axles when the rear end went out. However I was told there were some shim adjustments that would need to be made when new parts were installed and I don't know about it.
My diff tag reads S724S 5 5 8 8 6K21
I've had the diff apart before to change the axles when the rear end went out. However I was told there were some shim adjustments that would need to be made when new parts were installed and I don't know about it.
My diff tag reads S724S 5 5 8 8 6K21
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From: Sweden
yeah I did the intake, fuel injectors, and that stupid leaking valve cover that was under the intake. Regrettably I did not take the opportunity to work on the valves themselves- that was my main opportunity to do it. I really hadn't researched everything I needed to have and know to do that and didn't want to make it a 2 or 3 day job.
Runs smoother, maybe a bit more powerful. Idles quiet. Nice, but there's still a lot of room for improvement, and people kept saying the rear end ratio was the key.
Runs smoother, maybe a bit more powerful. Idles quiet. Nice, but there's still a lot of room for improvement, and people kept saying the rear end ratio was the key.
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From: The KeyStone State
Originally Posted by Dannym
My diff tag reads S724S 5 5 8 8 6K21
Your axle is an 8.8 Ford.
With 3.55 axle ratio, the C6 and the smaller(27-29" Dia) tires that E150s normally wear, your gearing is more than sufficient for any one of the 3 engines offered that year.
The real limitation is your engine and transmission if you want to feel more zoot.
I say keep the gearing where it's at.
-Jackson-
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He needs an od. I have an '85 with 3.50's and 31 (nominal) inch tires. In third, it runs up past 2500 at highway speeds, and would be tach'd out at 75.
Just save up the nickles and dimes and swap in a AOD or a Gear Vendors. At the price of gas, you'll have the money back in a few years.....
Just save up the nickles and dimes and swap in a AOD or a Gear Vendors. At the price of gas, you'll have the money back in a few years.....
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From: Sweden
But it's certainly not getting tach'ed out. The rpm doesn't sound all that high but the thing is there's just no more power available at this rpm. Yet downshifting will get more power. So I'm looking at it and if I did manage to get an AOD in there I don't understand how putting it into OD- further lowering the engine RPMs- would be helpful.
Have you done such a swap? What happened?
Wouldn't this require swapping out part of the column? The shifter doesn't have an OD position.
Have you done such a swap? What happened?
Wouldn't this require swapping out part of the column? The shifter doesn't have an OD position.
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Originally Posted by Dannym
But it's certainly not getting tach'ed out. The rpm doesn't sound all that high but the thing is there's just no more power available at this rpm. Yet downshifting will get more power. So I'm looking at it and if I did manage to get an AOD in there I don't understand how putting it into OD- further lowering the engine RPMs- would be helpful.
Wouldn't this require swapping out part of the column? The shifter doesn't have an OD position.
Wouldn't this require swapping out part of the column? The shifter doesn't have an OD position.
May be out of left field, but check to see if there is a governor on the engine limiting top speed. 75 seems like a really low top speed...
Gear swaps in Fords are pretty easy from what I've read (never done it personally). Ford semi-floating rears are well known in hot rod circles because it's easy to swap out ratios by having an extra carrier assembly already set to go. It's covered in most shop manuals and your local speed shop would be a great source of info. It's been awhile since I've read the procedure (car mags I read 20 years ago), but basically you pull the axles, unbolt the drive shaft, then unbolt the carrier and remove it. Replacing the gears and setting the lash and gear contact can be done on the bench.
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Changing rear end gearing
The factory 3:35 gear in my 94 E150 conversion van with the 5.0 engine and automatic tranny did not give me enough RPMs to do anything with. I had my mechanic install a 4:10 and what a difference. A lot more pep, no bogging down and the few mileage, if anything, is better
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From: savannah,ga
you dont say what your engine is but Ill bet its
a 300 six
this engine starts running out of power at about
3500 rpm
this engines cam is built for torque not h.p.
when its run up to 4000 rpm it sounds like a 302
at 7000 rpm
a 300 six
this engine starts running out of power at about
3500 rpm
this engines cam is built for torque not h.p.
when its run up to 4000 rpm it sounds like a 302
at 7000 rpm
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From: Sweden
Originally Posted by Ian F
Replacing the gears and setting the lash and gear contact can be done on the bench.
Book says it's an 8.8" integral carrier.
I would just need the pinion and ring gear set to change the ratio, right?
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The mechanic ordered the ring and pinion assembly and installed it as a unit. He said something about knowing in just a few minutes after he installed it as to how much time it would consume as to the lash adjustment. I know it has to do with the meshing of the gears and that if you do not get it right, you get a howl. His being very experienced at this and me not made it an easy decision to let him do it.
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Originally Posted by ttaylor530
The mechanic ordered the ring and pinion assembly and installed it as a unit. He said something about knowing in just a few minutes after he installed it as to how much time it would consume as to the lash adjustment. I know it has to do with the meshing of the gears and that if you do not get it right, you get a howl. His being very experienced at this and me not made it an easy decision to let him do it.
