Author Topic: 1980 Toyota 4x4 - re-gearing needed for 33” tires?  (Read 415 times)

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bcarroll76

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1980 Toyota 4x4 - re-gearing needed for 33” tires?
« on: Aug 03, 2020, 04:43:36 PM »
Howdy, just bought my son a 1980 Toyota 4x4., from what I can tell it has 4.37 gearing.  Should this truck have different gearing to accommodate the 33” tires?  Will take it hunting sometimes, but typical driving to school and back, no crawling or mudding.

Reason I ask is that the previous owner chewed up the diff and I was concerned if it was from the bigger tires.

Thanks all!

blackdiamond

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I ran 4.10 gears with 33s on my ‘85 truck and found it unacceptable so went to 4.88s. I don’t think damage should be expected in your case, just a lack of “go” power.
1989 4Runner: Dual Ultimate (Inchworm front & Marlin 4.70 rear), Marlin Twin Stick, 1200-lb clutch, 4.88 R&P, Aussie Front, Detroit rear, 30-spline Longs, Long hub gears, ARP hub and knuckle studs & 35x12.50 Cooper STT PRO tires.  Marlin rear bumper & sliders.  FROR front bumper.  SAS with Alcan springs & Rancho 9000XL shocks.  Budbuilt Bolt-on traction bar.  Custom Interior Cage by Those Guys Rod and Customs.

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RUGER

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when i got my 83 it had 4.10 and i did lift and tires first. i had to really milk the clutch with the 35s and yes power was an issue. eventually came gearing and decided on 5.29s and it was a ton better.

haveing big tires on stock ratio shouldnt hurt the gears, just wearing clutch faster.

fer yer setup 4.88 is about right.

jack up yer truck and spin a tire and count how many times it takes fer yer driveline to make a revolution. this will give you a rough estimate of what ratio you have. do it fer both axles. i bought a truck and found that it had different ratios front and back.

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redneckcustoms13

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4.88 would be a good upgrade. But I have an 81 with 4.37, 4 speed, and 33s. It does just fine. Not the fastest on acceleration, but it will do interstate speed with no problem.
83 long bed 2wd sas, 3rz, w56, duals with 4.7 rear, 4.88 elock front, spartan rear, 39.5 iroks
01 double cab hunting truck
06 tacoma street truck

bcarroll76 [OP]

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Thanks all, @Ruger,  I will for sure check to ensure front/back match. 

I think I will stick to the 4.37 since it is just my son and he DOESNT need to be in a hurry anyhow ;)

I am in CO and can’t find a 4.37 3rd member locally to save my life!  Any of you have ideas on places to look for getting one?  We are a bit new to the Import 4x4 family.

Thanks lot guys!

bcarroll76 [OP]

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Update - bit the bullet and replaced front and rear with 4.11 gearing.  Runs great

Thanks everyone!

RUGER

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glad its working out fer you.

RUGER :usa: :beer: :usa:
:usa: GOD BLESS AMERICA :usa:

"the hag" 83 toy with 5" all-pro lift, marlin crawler dual case #1011 and marlin hy-steer, 35s, 5.29's, exo cage, yada, yada, yada. she's back in black.

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84 Grand Waggy
77 Scout II SS

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liveoak

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Howdy, just bought my son a 1980 Toyota 4x4., from what I can tell it has 4.37 gearing. 
Should this truck have different gearing to accommodate the 33” tires
Update - bit the bullet and replaced front and rear with 4.11 gearing.  Runs great
you went from 4.37 to 4.11 gearing? that is the opposite of the advice you received. seems like you made it worse.
should have at least gone 4.56
« Last Edit: Sep 03, 2020, 10:00:06 AM by liveoak »

79coyotefrg

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Update - bit the bullet and replaced front and rear with 4.11 gearing.  Runs great

Thanks everyone!

I realize you got what you could find on a budget but its not too hard to find 4.37's I ran my truck for about 12 years with 4.37's and 32's
NOW I have 5.29's and 35's and my speedo is perfect
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blackdiamond

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I realize you got what you could find on a budget but its not too hard to find 4.37's I ran my truck for about 12 years with 4.37's and 32's
NOW I have 5.29's and 35's and my speedo is perfect

Wait...but my speedo is perfect with 4.88's and 35's.  You must have full height 35's because I think the math with 4.88's lines up with 34 inch tires.
1989 4Runner: Dual Ultimate (Inchworm front & Marlin 4.70 rear), Marlin Twin Stick, 1200-lb clutch, 4.88 R&P, Aussie Front, Detroit rear, 30-spline Longs, Long hub gears, ARP hub and knuckle studs & 35x12.50 Cooper STT PRO tires.  Marlin rear bumper & sliders.  FROR front bumper.  SAS with Alcan springs & Rancho 9000XL shocks.  Budbuilt Bolt-on traction bar.  Custom Interior Cage by Those Guys Rod and Customs.

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Gnarly4X

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If your engine is a 1980 20R, the peak torque is a low 2400 RPMs, with peak HP at 4800.

If the transmission is an L43 4 speed, 4th gear is 1:1.

Typically the choice of gearing is based on where your peak torque is and what RPMs your want it to be in the RPM range for the speed of your pickup.

In other words, with 4.11 R&P and 33” tires, in 4th gear your RPMs will be 2511 at 60 MPH.  At 75 MPH your RPM will be 3139 in 4th gear.

In my 1986 XtraCab, 22RE with a W56 5 speed, 30” tires, 4.56 R&P, at 80 MPH my RPM is about 3200 in 5th gear, which is just about in the middle of my peak torque curve and a comfortable cruise RPM.

Gnarls.
« Last Edit: Sep 13, 2020, 04:36:16 AM by Gnarly4X »
1986 XtraCab SR5 22RE 5speed W56B, ~26,000 MI after break-in, DIM (Did It Myself) rebuilt engine - .020" over, engnbldr RV head, OS valves, 261C cam, DT Header. https://imgur.com/oACTHTR

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Ran 4.37's on my 80 with no issues but the motor was 22r/20 swap and the trans was swapped to a 5 speed. Don't know how it acts with the 4 speed and a stock 20r but if you swap gears go with 4.88's if you go with 5.29's you may have to increase the size of the notch in the housing in order to get the ring gear to fit through which if cut too big will leak.
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Gnarly4X

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Ran 4.37's on my 80 with no issues but the motor was 22r/20 swap and the trans was swapped to a 5 speed. Don't know how it acts with the 4 speed and a stock 20r but if you swap gears go with 4.88's if you go with 5.29's you may have to increase the size of the notch in the housing in order to get the ring gear to fit through which if cut too big will leak.

What size tires?

Gnarls.
1986 XtraCab SR5 22RE 5speed W56B, ~26,000 MI after break-in, DIM (Did It Myself) rebuilt engine - .020" over, engnbldr RV head, OS valves, 261C cam, DT Header. https://imgur.com/oACTHTR

 
 
 
 
 

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