I have a 98 S-cab F150 with the 4.6L V8 and 3.08 rear end. (I got a real good price on this!!) I pull a 24' travel trailer and want to upgrade the rear end when I get new tires. I'm going from P235-70-R16 to LT 245-75-R16 and I know this will effect the rear end ratio and know that I must correct this. I'm thinking a 3.73 limited slip to help with the low-end torque but don't know if this is right/feasible. Any advice and cost estimates would be appreciated. Thanks!

 

ive been wanting some new gears also, ive got a 4x4 and have upgraded to a 285/75 heavy mud tire. everyone reccomends not to try it by yourself, a new set of gears for one axle is around 300.00 or less. probably cost close to a grand to put it in. im probably going to upgrade to a 4.56. 3.08 is real high geared definetly not made for towing. minimum would be 3.73 just remember when u upgrade tires it will raise your ratio again so your 3.73 will be between 3.55 and 3.08. plenty of experts around just check the 4 wheeler magazines and call the adds theyll sqaure u away.

 

penguin149- From what you described, 3:73s would be minimal in my opinion (wanting towing + taller tires). I would at least consider 4:10s also; there is plenty of top end. Very good time to add the LS while the rear is broke down that far anyway. Gears from several mfgrs run $200, and the lowest install prices I've seen locally are $300-$400 for 1)rear axle.

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2000 F-150 XL, RC, LB, 5.4L, 4R70W, 3.55LS,
Class III tow, Payload #3, & Convenience pkgs.,
4-wheel disc/ABS, Chestnut/Parchment 40/60,
Ford bedliner w/Paintsaver & gas/wheel/spare locks,
K&N F.I.P.K. w/Outwears pre-filter, Superchip,
Dynomax ultra-flow welded 3" cat-back w/ 3" Y-pipe,
Hellwig front & rear anti-sway bars, Rancho RS 9000s,
Mobil 1, K&N oil filter.

 

penguin, ok here's the scoop. You've got a high geared(low number)gear ratio. Not great for towing or for that V8. Now, you have 235/70s right now which are 29" tall, and you are switching to a 30.5" tall tire. My truck came stock with 255/70R16s (30.1" tall) and the 3.55LS rearend. My point is that a switch to 3.55(LS) is gonna give you TONS more torque and hp, but still keep stock fuel mileage. If fuel isnt a factor, 3.73(LS) will give you a bit more power but 3.73 and 3.55 are kinda close in comparison. If it were me i'd be considering 3.55(to keep stock fuel eco.) or 4.10 (TONS, and i mean, TONS more power) because 3.73s arent that much greater than 3.55s in my opinion and i've driven both. If go with the 4.10s then fuel mileage will go WAY down though. But it will be a totally different truck either way. Hope this helps...

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-Brandon Warford
97 F150 4x4 Sport Brt. Red SuperCab
4.6l Triton V8
3.55LS
3" Performance Acc. Body Lift
Clear Corner Lenses
315/75R16 Yoko. Geolander MTs
American Racing Atlas 16x10
Pioneer 8000 3D series
Boston Acoustic 5x7s
Sony Xplode 4ch Amp
(2) 8" RF XLC Subs
True Dual Exhaust
--(2) Stage 3 Flows (Exits like the Lightning)
Custom 4x4 Sticker
Viper Alarm
FUTURE MODS:
4.56 gears
Repaint around Headlights where clearcoat is coming off >=(
Possibly a Manik Brush Guard and Roll Bar--we'll see
Thats about it for now!
Killintime4fun@aol.com
"THROUGH the river and OVER the woods to grandmother's house we go."

"...the road curves to the right and there are a lot of signs that say you cannot turn left...TURN LEFT."

 

penguin149
Go over to the Lightning forum, I bet there is someone who took out there 3.55LS that might be willing to sell you there gears for a cheep price. I know a bunch of them have put 3.73 or 4.10 gears in there trucks.