Mismatched Front/Rear Axle Gears 4.56/3.73 - Pirate4x4.Com : 4x4 and Off-Road Forum

quikchevyz71 · 03-14-2007, 09:20 PM

I am just wondering exactly what happens when you use 4wd with mismatched front and rear axle gears? I know it isn't good and they will be fighting each other but I have never done it and was wondering if anyone has and what actually happens? I'm just curious because I am selling my 1996 Chevy Silverado which has 4.56's in the rear and I never got around to putting 4.56's in the front, so it's still stock 3.73 in the front, and I never use the 4x4 anyway....but I just want to tell the guy who is buying my truck exactly what will happen if he uses 4x4 without re-gearing the front. Thanks for the help

trkklr77 · 03-14-2007, 09:28 PM

depends on the situation,

if your are running appropreatly mismatched tires, nothing
if you have a part time tcase [205,208,241..... not the 203] it will 100% bind up and something WILL break.
a 203 has a differental built into it and will allow some slip but not that much.
it will wear teh living shit out of the tires if it is engauged.

trkklr77 · 03-14-2007, 09:30 PM

ther eis a formula somewhere that can tell you what size tires to run with which gears SPICIFICALY FOR MISMATHED GEARING.

it may be % of gear ratio offset = same % of tire diam offset

positrack@earthlink. · 03-14-2007, 11:12 PM

Just bolt some 37s up in back and tell the buyer it's part sand rail!

No, seriously, nothing good can come from this assuming 4 identical tires. You should get the front gears put in, or at least tell him he's gonna have to before he uses the 4WD.

svt150j49 · 03-14-2007, 11:52 PM

if you do this your going to break something... ive been there... 3.55s up front and 4.88s in the rear. it will plow in the snow, gravel is OK, mud you couldnt tell, but dirt it will feel like the truck is bending in the center like a stick. your truck is goings to try to spin the front end almost a full turn compaired to the rear... id tell the guy to gear it or not use it. those front ends arent cheap-and neither is the transfercase...

or

bjb · 03-15-2007, 09:50 AM

I had an old flatfender I changed the front axle in and didn't even think about the gears. 5.38 rear, 4.88 front put it in 4x4 at loon lake and ran the whole rubicon put 70 lbs. of air in the tires and chirped and hopped all the way. Never broke anything (real light with skinny tires and 4 banger) but I don't recommend it.

Dirty "OLE" Man · 03-15-2007, 01:40 PM

Something is going to ******* break. That is about the dumbest & dumber!

Dhmoto111 · 03-15-2007, 01:43 PM

i replaced an np231 on a 2 door blazer that was broke in half because the guy didnt want to put new gears in the front

Donahue · 03-15-2007, 04:51 PM

Quote:

Originally Posted by quikchevyz71

I am just wondering exactly what happens when you use 4wd with mismatched front and rear axle gears? I know it isn't good and they will be fighting each other but I have never done it and was wondering if anyone has and what actually happens? I'm just curious because I am selling my 1996 Chevy Silverado which has 4.56's in the rear and I never got around to putting 4.56's in the front, so it's still stock 3.73 in the front, and I never use the 4x4 anyway....but I just want to tell the guy who is buying my truck exactly what will happen if he uses 4x4 without re-gearing the front. Thanks for the help

to specifically answer the question, the front tires will turn faster than the rear tires. on any high traction surface, it will bind and break something

wtr40rock · 03-15-2007, 05:18 PM

it would either pull apart or the axles would pull towards each other

03-14-2007, 09:20 PM	#1 (permalink)
quikchevyz71 Registered User Join Date: May 2005 Member # 47420 Location: Vacaville, CA Posts: 18	Mismatched Front/Rear Axle Gears 4.56/3.73 I am just wondering exactly what happens when you use 4wd with mismatched front and rear axle gears? I know it isn't good and they will be fighting each other but I have never done it and was wondering if anyone has and what actually happens? I'm just curious because I am selling my 1996 Chevy Silverado which has 4.56's in the rear and I never got around to putting 4.56's in the front, so it's still stock 3.73 in the front, and I never use the 4x4 anyway....but I just want to tell the guy who is buying my truck exactly what will happen if he uses 4x4 without re-gearing the front. Thanks for the help __________________ 2007 ChevySilveradoClassic, 14" lift, 4.88, 38" toyos, k&n, 1 chamber, superchip, 2-10" subs

03-14-2007, 09:28 PM	#2 (permalink)
trkklr77 skullfuckery Join Date: Apr 2004 Member # 29016 Location: galt ca, because i wanted my own backyard Posts: 15,218	depends on the situation, if your are running appropreatly mismatched tires, nothing if you have a part time tcase [205,208,241..... not the 203] it will 100% bind up and something WILL break. a 203 has a differental built into it and will allow some slip but not that much. it will wear teh living shit out of the tires if it is engauged. __________________ Impeach or revolt, which will it be? buy my quad http://www.pirate4x4.com/forum/vehic...00-2500-a.html I WILL TRADE FOR A ROAD WORTHY 55-57 or 71-87 CHEVY 2WD PICK UP

03-14-2007, 09:30 PM	#3 (permalink)
trkklr77 skullfuckery Join Date: Apr 2004 Member # 29016 Location: galt ca, because i wanted my own backyard Posts: 15,218	ther eis a formula somewhere that can tell you what size tires to run with which gears SPICIFICALY FOR MISMATHED GEARING. it may be % of gear ratio offset = same % of tire diam offset __________________ Impeach or revolt, which will it be? buy my quad http://www.pirate4x4.com/forum/vehic...00-2500-a.html I WILL TRADE FOR A ROAD WORTHY 55-57 or 71-87 CHEVY 2WD PICK UP

03-14-2007, 11:12 PM	#4 (permalink)
positrack@earthlink. _Differential 'Dozer Join Date: Jul 2005 Member # 51113 Location: Princeton, IL Posts: 568	Just bolt some 37s up in back and tell the buyer it's part sand rail! No, seriously, nothing good can come from this assuming 4 identical tires. You should get the front gears put in, or at least tell him he's gonna have to before he uses the 4WD. __________________ '76 K20, 400, NV4500, LoMax 205, 14b/Detroit/discs, D60, 4.56s '78 K30, 400, TH400, 203, 14b, D60, 4.10s '79 Cherokee, 360, T18, D20, W.T.D44s

03-14-2007, 11:52 PM	#5 (permalink)
svt150j49 Damn you chuckie... Join Date: Jan 2007 Member # 85316 Location: Redding Posts: 2,937	if you do this your going to break something... ive been there... 3.55s up front and 4.88s in the rear. it will plow in the snow, gravel is OK, mud you couldnt tell, but dirt it will feel like the truck is bending in the center like a stick. your truck is goings to try to spin the front end almost a full turn compaired to the rear... id tell the guy to gear it or not use it. those front ends arent cheap-and neither is the transfercase... or __________________ 1996 F150 - Supercharged 5.8L, E4OD, Vortech S-trim, PSD Intercooler, 15 psi , 1356, Dana 60, 10.25, 5.13 gears, welded rear diff, 14" Air/Coilovers. Check it out: Build thread: Here The un-named buggy - 2.3L, lotsa tube, and FJ80s.

03-15-2007, 09:50 AM	#6 (permalink)
bjb Registered User Join Date: Nov 2005 Member # 56602 Location: Sacramento/Elk Grove/Sloughouse Posts: 983	I had an old flatfender I changed the front axle in and didn't even think about the gears. 5.38 rear, 4.88 front put it in 4x4 at loon lake and ran the whole rubicon put 70 lbs. of air in the tires and chirped and hopped all the way. Never broke anything (real light with skinny tires and 4 banger) but I don't recommend it.

03-15-2007, 01:40 PM	#7 (permalink)
Dirty "OLE" Man Registered User Join Date: Feb 2006 Member # 66865 Location: Waxahachie, Texas Posts: 104	Something is going to ******* break. That is about the dumbest & dumber!

03-15-2007, 01:43 PM	#8 (permalink)
Dhmoto111 Registered User Join Date: Jan 2005 Member # 42045 Location: Lubbock TX Posts: 249	i replaced an np231 on a 2 door blazer that was broke in half because the guy didnt want to put new gears in the front

03-15-2007, 05:18 PM	#10 (permalink)
wtr40rock Registered User Join Date: Jan 2007 Member # 85265 Location: Fort Mill, SC Posts: 531	it would either pull apart or the axles would pull towards each other __________________ the beatings will continue until morale improves.

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