3.55 to 4.56 Gear Swap Complete!
 

Just picked up truck from having 4.56's transplanted into the front and rear diffs.

To make a long story short, I AM HAPPY! What a difference. The acceleration is great, the truck finally pulls like it should. I highly recommend this mod if you are considering this type of thing.

A local 4X4 shop did the gears, I did the speedometer. The Abbott Electronic Ratio Adapter is great. You can compensate to within 1/2%, which put my speedo dead on where it should be. My change was about 28.5%, and you cannot get a speedo gear for that amount of change.

I will post fuel milage results after this first tank is history. I am expecting about 1 MPG loss based on the testing I did before the change.

I will wait about 500 miles before any hard stuff, but after that, watch out you Z-71 Shovie drivers!


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98 F-150 4X4 Ext Cab ORP 4.6L, 4.56 Gears, Superchip, Gibson Cat Back Single exit exhaust, TransGo Performance Shift Kit, K&N Filter, Downey SST Tonneau, Abbot Electronic Ratio Adapter. Future: shorty headers.

I just have a few questions as I am planning 4.10's possibly 4.56's depending on your gas milage returns. What all did you have to buy? Gears, shims, gaskets, and fluids. Reason I ask is the shop I asked about doing my install they said I had to change the carrier. i had not heard any others talking about this before. What did the whole thing run parts and labor? Thanks in advance.

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97 4X4 Flareside 4.6 5-Speed, Superchip, ASP underdrives, Airaid, Dynamax headers, Borla Cat-back, 5% Tint, 285/75/16, 16x8 Baha's, Rancho 9000's.

Soon to come:
3" body lift, 315/75/16 BFG KO's

wschubbe-
Take it easy on the new gears for a while. Everything I've read and been told says that proper break-in is essential for longevity.

ole blue-
If you've got the 8.8" differential (definitely up front), there are all kinds of gear ratios that don't require a new carrier. All you need is the install kit (seal, shims, etc.) the ring, pinion, fluid and probably bearings- might as well change them while you're there- depending on the number of miles on the truck. Cost me about $1500 for front and rear.


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1997 4x4 Expedition- 4.6L, true dual exhaust w/glass-packs, K&N air filter, SuperChip, airbox mods, Edelbrock shocks, 285/75R16 BFG ATs, 2000 "XLT" wheels, 4.10 gears, Auburn LS, Clarion In-dash CD player, Smitty Bilt push bars and nerf bars.

2000 4x2 F150 XLT Reg. Cab LWB- 5.4L, Tow Pkg, 3.55LS, CD player,Remote Keyless Entry, Sliding back glass, Special Appearance Pkg., tinted windows, Line-X bedliner, and Prime #155 wheels.

http://members.visualcities.com/NoMo

OLE BLUE,
I just did a swap from 3.55s to 4.10s in my 99 F150 4x4. The change was awesome to say the least. The shop you talked to obviously had no idea what they were talking about because the 8.8" axles do not have a carrier split at any ratio.These diffs use the same carrier for all ratios,so a new carrier is not needed.
My truck has the 8.8 front and rear which may or may not be the same as yours.Total cost for my install was about$1400.00.This included both front and rear ring and pinions,master install kits,6 quarts of Amsoil synthetic gear lube,a bottle of Ford friction modifier,and a Superchip custom burned to recalibrate my speedometer.When you shop for your gears be sure to buy a quality product. I went with Precision Gears as that is what was recommended to me by the machine shop that did my install.There are several brands that are much cheaper but as I'm sure you know,you get what you pay for.
Hope this helps. Let me know if you need more info.

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99 F 150 4x4.ORP,S/B 4.6 4.10 gears, Gibson 3" cat back. K&N filter. Soon to be Superchiped

Ole Blue,

Nomo and Jarrettruelz88 have it right, in addition you will need to compensate for for the increased drivetrain speed by replacing your speedometer gear or installing an Electronic Ratio Adapter (99 and Up can be compensated for with the Superchip)depending on your setup.

Also, setup is critical! I thought of doing it myself, but came to my senses when I found out how hard it is to set a differential up correctly.

Good Luck, any more questions let me know.

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98 F-150 4X4 Ext Cab ORP 4.6L, 4.56 Gears, Superchip, Gibson Cat Back Single exit exhaust, TransGo Performance Shift Kit, K&N Filter, Downey SST Tonneau, Abbot Electronic Ratio Adapter. Future: shorty headers.

[This message has been edited by wschubbe (edited 03-22-2000).]

[This message has been edited by wschubbe (edited 03-22-2000).]

Author Topic: 3.55 to 4.56 Gear Swap Complete!
wschubbe

Hi, What size tires do you have? What is your RPMs at 70 mph? I have been thinking of doing the same thing to my rig, bu thought 4.56s were too steep unless you had really big tires, witch I do not. I was thinking 4.10 or 4.35. Does the gear change make it seem as if your gears are also closer together? I live at 6000ft so my trucks a dog, even with all the mods I already have.

Thanks
Darren

my profile

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97' F150 Lariat S/C long bed 4x4 3:55LS 4.6L auto...SuperChip, Air Raid, 40 series Flowmaster cat back.
Colorado Springs, CO

Prper break in???? what are they talking about , i am a mechanic and i have put many rear diff's togther and i have never heard of a break in period, what like drive nice for 2000 ,miles??? If the rear end is set up properly you DO NOT have any break in period go out and beat the hell out of it. Enjoy your new gear change. you should check if for leaks after about 50 miles other than that smoke them tires!!! also what size tire do you have??.... that seems to be alot of gear for a stock tire size.

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*2000 blk xlt f150
*5.4 4x4 3.55 ls
*sc orp pkg
*tow pkg, 17 inch wheels
*herculiner,remote start
*flowmaster, air box mod
*bfg ko's A.R.E. cap
*sony 10 disc cd player
*k&n air filter
*superchip
* havoline synthetic oil
****mods to come*********
harley davison hitch reciver plug.
removing stock cab steps& installing westins.

Darren Dude

I have the stock 17" ORP tires (31.6 diameter). My truck runs 2375 RPM at 70 MPH. This is the high end of the speed I will drive, most times I am around 60 MPH which puts me around 2,000 RPM. This engine pulls extremely well above 2,000 RPM and awesome above 2,200 RPM. In a nutshell, I do not believe this is too much gear for this engine/transmission/tire setup.

I originally wanted 4.33s (or 4.30s) but could not find them in a reverse cut for the front differential. I felt that 4.10s would not be enough, so I went with the 4.56s.

The truck does go through the shifts faster, however, the shifts feel very appropriate for the throttle position, load, etc. With the 4.6L engine, ORP, and auto transmission, I would not hesitate to put these gears in again. If you have the 5 speed, I would go with the 4.10s or even 3.73s (just an opinion).

If you want to see what having this gear set would be like, take your truck and drive it down the road without the overdrive on at about 60 MPH. That is how your truck will pull and drive at 70 MPH in overdrive with the new gears (2,375 RPM). I did this over a 300 mile trip and lost less than 1 MPG over my average.

If you decide to go for it, let us know what setup you go with!


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98 F-150 4X4 Ext Cab ORP 4.6L, 4.56 Gears, Superchip, Gibson Cat Back Single exit exhaust, TransGo Performance Shift Kit, K&N Filter, Downey SST Tonneau, Abbot Electronic Ratio Adapter. Future: shorty headers.

Darren Dude

I also see that you do not have the ORP in your signature, you must have the standard tires (probably around 30" diameter). In this case, you would probably be better off with the 4.10's, with the 4.30s you probably will not find a reverse cut for the front.

Also, if you do have the standard tires, you will have to figure out what exact RPM you would run with the new gears before you tried the test I recommended in the previous post (since the RPM will be different with different tire size).

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98 F-150 4X4 Ext Cab ORP 4.6L, 4.56 Gears, Superchip, Gibson Cat Back Single exit exhaust, TransGo Performance Shift Kit, K&N Filter, Downey SST Tonneau, Abbot Electronic Ratio Adapter. Future: shorty headers.



[This message has been edited by wschubbe (edited 03-23-2000).]

Steve g,

NO BREAK-IN PERIOD! What are you friggin HIGH?? and you call yourself a mechanic!!:-(

OK then try this, next time you rebuild a street motor (new crank, bearing, pistons, cams, etc,etc,etc put it all back together, fill w/ fluids start it up and rev the sh*t of out the motor, do burn outs at every light, over heat the motor. The motor will not last to long! The same goes w/ a new gear set. There is a tremondous amount of friction (heat) build-up between a new gear set, especially the trailing edges. This is why it's important not to run the gears for more than 12 to 15 miles. The portion of the gears that actually make contact (mesh together) have to be properly seated and worn in. If the gears are allowed to overheat they will 1. over heat the gear oil 2. Break down the effictive lubericant properties (which will not properly cool the gears), 3. will warp and/or weaken the gear teeth. You can ruin a brand new set of gears in a matter of a few miles, if not broken in properly.

read-on;
http://www.ring-pinion.com./Gear%20Talk/NewGear.html

I posted this back in Jan;
rockcrawl,
WOW with a big "W", you HAVE to post a msg here when you get your truck back!! you are going to be smiling from ear to ear ;-) Just remember to ask about PROPER break in procedure for the new gears ~ this is VERY important~
I was told to drive the truck "EASY' for NO MORE than 10-12 miles, (if going on the HWY then drive at normal speeds, just easy starts) If driving in city traffic, NO jump starts!! the new gears have to SEAT themselves and wear off the coating from the factory) Then let axles cool COMPLETELY. Then repeat one more time, (10 to 12 more miles of easy driving). If you go ape sh*t of the line w/ new gears you will overheat them and the oil weakening the steel. This means shorter life (remember new gears generate LOTS of heat and this will quickly heat up that new oil and brake down the properities faster than you can say peter rabbit.) The pinion gear is turning much faster w/ the 4.56's. sorry for rambling on here, but the shop who installed mine was very serious about break in procedures.


Best of luck.

F&B's

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98 F-150 XLT, SC, SWB, 2WD, Pac. Grn., 4.2L auto, 4.10 gears w/ LS, Tow Pkg., BFG AT's 265/75/16, K&N air filter, Dynomax muffler, Superchip, Edelbrock shocks, Hellwig sway bar, 3" body lift, signal mirrors, ...tons of cosmetic products



[This message has been edited by franks&beans (edited 03-23-2000).]

Remind me to NEVER,EVER,EVER let Steve g touch anything of mine. If a break in period is not needed then why do ring and pinion manufacturers tell you in the install instructions to run the new gears for 20 miles then let them cool completely.If you have done as many as you say, I'm suprised you did not know that. Is it because the things you build dont turn up or run faster than 20 mph so proper seating is not as important.
Just wondering, Have a nice day

jarrettruelz88,

Hello,

If you think the 4.10's are awesome, just wait until you install the Superchip! It is a whole new driving experience. Even w/ my 4.2 auto , this truck moves out!!

Happy truck'in

F&B's


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98 F-150 XLT, SC, SWB, 2WD, Pac. Grn., 4.2L auto, 4.10 gears w/ LS, Tow Pkg., BFG AT's 265/75/16, K&N air filter, Dynomax muffler, Superchip, Edelbrock shocks, Hellwig sway bar, 3" body lift, signal mirrors, ...tons of cosmetic products



[This message has been edited by franks&beans (edited 03-30-2000).]

Wow!


[This message has been edited by Y2K 7700 4x4 (edited 07-30-2000).]

i have 3.55 with a 4.6L and bigger tires.they took my 3.55 to a 3.38.i lost power a 1 mpg.i put headers exhaust,KaN fipk,t- body spacer,chip,jacobs ignition.the power now is great,i was going to chang to a 4.30 or so,but when i priced it at$1500,i said no way .i can buy a powerdyne supercharger for $2000.why did you chang the gears instead of putting on a supercharger.how much more take off does the truck have now.