LUVTruck.com

I needing some assistants , I recently bought a all original 1974 luv , it has the stock 1.8 motor stock 4 speed tranny in it . When I'm driving it seems to be too low geared . I was told it had 4.56 gears it in , well today when I went to order some 3.73 gears for the stock rear end, and the guy needs to know what stock gears are . I said 4.56 and he said they didn't come with them that's not it .long story short I'm lost. He told me to look for the rear end stamp or tag there's nothing . I basically wanna leave everything as stock as possible and be able to drive it down the high at 70-80 mph now At 45-50 mph it's pushing pretty hard . Any advice or input ?

_________________
My first Luv

4.56 is what they came with in 74.

Thank you i was hoping that I wasn't crazy . So would putting 3.73 gears in it fix the top speed of 55mph issue ? Or is there a better ratio to put in it ? Anyone know a website I can order them from ?

_________________
My first Luv

Gearing it up is a tradeoff. You would probably be trading some acceleration for top end driveability, but not necessarily increased top end speed--your 1.8 may not have the power to to that. I think the 3.73 rear end may have been standard in some years, but I don't know 1st-generation LUVs well enough to say for sure. Plenty of folks here will know the answer to that one.

They're not available from the factory, or aftermarket sources. Your only source is the used market.

Jack

_________________
'83 Isuzu P'up Diesel LS - Original Owner
JoeIsuzu@IsuzuPup.com
IsuzuPup.com

4.10 gears are going to be a lot easier to find. Most automatics and all 4x4s had 4.10s.

My 76 had 4.56 gears. I used to drive it at 65-70 all the time. I had an 80 with 4.10s later and the difference was quite noticeable. It liked 70mph more than the 76.

Any change you make will also affect the accuracy of your speedometer.

Good point. And believe it or not, replacement speedometer drive gears are actually still available. Usually, it's just a matter of choosing the correct drive gear for the rear end that you have.

Jack

_________________
'83 Isuzu P'up Diesel LS - Original Owner
JoeIsuzu@IsuzuPup.com
IsuzuPup.com

I wish mine ran 75mph, in 4th gear on flat ground it will run 50-55mph when the cruisin speed seems to be more like 45-50 . I'm not a expert at anything just seems like it's working it's butt off anything over 50-55. Downhill I gotta let off the accelerator cause it seems to be working too hard. According to a couple different phone apps , snap chat app and the school zone sign my speedo is already 5 mph . Any ideas of what to do in my shoes ? Like I said I want to go original as possible for the time being , until I can go threw everything . I basically just want to be able to 75-80mph I wouldn't pull anything with it or even haul anything in the bed, didn't want to change the tire size I'm not really trying to do burn outs or anything like that .

_________________
My first Luv

At 70mph, these trucks with the 4.56 gears will sound like they're about to explode. They will handle it though. If your speedo is off, your tires may be too small.

The quickest and easiest solution is to swap out rears. 4.10 will get you cruising a lot happier on the highway. 3.73s would be even better, but will likely be hard to find and identify.

You could also look at swapping in a 5 speed if the 4.10s don't get your RPMs low enough.

Thanks a lot man I appreciate it . Easier to order them new or take them used out of something ? If used what all can I get them out of that will match up? I'm a rookie to the luv game so all advice and Options are a huge help. And what is the standard tire size I should be running ?

_________________
My first Luv

If your speedo is reading fast you probably have smaller than stock tires, which will make the rpms higher at cruising speed. If so you are only making the too-low-gears problem worse. A 5mph too fast speedo because of small tires at 50mph is about 11%, which makes your effective final drive ratio more like 5.06 gears than 4.56s. This indicates your tires may be as much as 3" smaller diameter than stock. The door pillar sticker should have the stock tire size, compare that to what you actually have.
Each 1" difference in tire diameter changes the effective final drive ratio 3.5-4%. To see how your truck would perform with a different gear ratio borrow a couple of wheels & tires that are larger diameter & go for a test drive: 3" bigger than your current tires will make your truck perform as if it had 4.10 gears; 6" bigger as if it had 3.73. Be careful, your speedo will read dramatically lower than actual speed. If the larger tires give you the power curve you want then swap your rear 3rd member for one with the correct gearing & your current tires will give you the same power curve.
For gasoline powered trucks most manual tranny LUVs & P'ups from '77-'87 came with 4.10 gears. '78-'80 LUVs(maybe other years) with auto transmissions came with 3.73 gears. Around '84 there were a few 1.9/4sp P'ups with 3.42 gears. Diesels had 4.10s, 3.73s & 3.42s depending upon the engine/tranny combo & the model year. There is not a differential tag to identify the gear ratio, the only sure way is to count ring & pinion teeth: 4.56=41/9; 4.10=41/10; 3.73=41/11; 3.43=41/12. New parts to change gears are too expensive if you can even find them, so just locate a used and swap 3rd members.

_________________
'78 Chevy LUV,1.9,4sp,headers,31's,SAS Dana 30,Dana 20,SOA rear w/Aussie Locker, rough body, bought new 12/4/78.
'87 Trooper,2.3,5sp,headers,31's,ball joint flip & spacer,Aussie Locker rear,Superwinch hubs,brush guard w/5.5K winch,more to come.

Seems I have 14's front and back the fronts are 185/70 14's and the tears are 235/60 14's . Sticker on door says
g.v.w.r 3950lbs
G.a.w.r
front 1600lbs
Rear 2650 lbs

_________________
My first Luv

14 is your wheel diameter. 235 60 r14s are about 25" tall. That's pretty close to stock.

The trucks are just slow. Changing ratios doesn't make it faster, it's not making enough power.

_________________

1979 4wd Mikado. G200, Gemini 250 Turbo, Clive Cam, Offenhouser Intake, JE Pistons, maXspeeding Forged Rods, Blow Thru Weber, Trooper 5spd, Intercooled

Yeah i had a 4.10 and was doing 3000rpm at 55mph
With my v6 and 5 speed with 17% overdrive I am at 2600rpm at 55.

3.73 won't put you anywhere near comfortable at 70mph.
You would need 3 08-3.23 range and the engine can't pull that gearing.
Swap to a 5 speed and the 3.73 and if that isnt enough you need a different engine. I think the later diesel luvs had a 3.42? Maybe?
My 4.3 pulls 70 real nice but it is over 3000rpm and wasting gas. Need a regear

_________________
Luvless
1980 Mikado-Sold.

1993 Lexus SC400 my Daily
2004 Yamaha WR250F my new love in life
2016 Toyota Camry my girls ride

I have to disagree with that. Many here have re geared and able to run at higher freeway speeds then before.

_________________
Certified pilots, looking down on people since 1903.

Right. These trucks aren't that powerful, but they WILL cruise down the highway just fine.

At 70mph with your tires:

4.56 = 4250rpm
4.10 = 3800rpm
3.73 = 3500rpm

Bear in mind that you have no overdrive, so unless you take the ratio way down, you're not going to "cruise" like a modern car. If you go much past 3.73, you're going to lose a lot of "off-the-line" power. The only way you're going to get the best of both worlds is to choose a moderate rear end gear and swap for a 5 speed. In the short term, a rear swap will make you a lot more comfortable.

The pup 5 speed is something like 14% overdrive so with a 3.73 that puts you at 3,010rpm at 70. Right about where you wanna be to make the torque to keep the speed going.

_________________
Luvless
1980 Mikado-Sold.

1993 Lexus SC400 my Daily
2004 Yamaha WR250F my new love in life
2016 Toyota Camry my girls ride

All this talk about gear ratio has me curious to know what mine is.

I have a newer 11k miles Ca stock 1.8 motor & carb w/ smog still hooked up, early 5 spd (rebuilt) trans upgrade & mine seems to scoots down the highway pretty good, when my foot is into it i can reach 100mph ... Okay... with a slight down hill I believe i still have a stock rear end , & running 14 inch tires & my speedometer gauge matches up when i pass by a speed radar sign.

Are there markings on the rear end that confirm what we have or we did we calculate that when it was apart ?

_________________
Previously owned 2 Luvs) 75 & 77 Fleet-side
3rd 77 Step fixing up aka The Yellow Submarine to Luv Ms (Sun)Shine=)
98 GMC Gas Guzzler~>The reason 4 my ~>3rdLuvNext2a66MALIBU =)
66 Chevelle The Oldest of all the vehicles I owned

From my earlier reply: "For gasoline powered trucks most manual tranny LUVs & P'ups from '77-'87 came with 4.10 gears." Stock gears in '77 were 4.10s.

_________________
'78 Chevy LUV,1.9,4sp,headers,31's,SAS Dana 30,Dana 20,SOA rear w/Aussie Locker, rough body, bought new 12/4/78.
'87 Trooper,2.3,5sp,headers,31's,ball joint flip & spacer,Aussie Locker rear,Superwinch hubs,brush guard w/5.5K winch,more to come.