Author Topic: 4.30 gears interchangeable with 4.37 gears?  (Read 142 times)

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Mojavewanderer

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4.30 gears interchangeable with 4.37 gears?
« on: Sep 15, 2020, 07:57:44 AM »
Hey everyone, I have a 1980 Toyota 4wd pickup with the stock 1980 only 4.37 differential gears. I blew up the rear end, and need to get it fixed, but 4.37 gears are pretty difficult to find. I was told that 4.30 gears were close enough to work without causing any problems. Is there any truth to that, or am I being fed a line of bs? Thanks!

blackdiamond

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Re: 4.30 gears interchangeable with 4.37 gears?
« Reply #1 on: Sep 15, 2020, 08:09:38 AM »
I think you can find sources to support a difference of 1-2% is workable. I think where Iíve seen different gear ratios on rigs in magazines they generally had the lower gear ratio in the front so that the front end was pulling rather than the back end pushing. Iíd guess that youíd be ok in the dirt where thereís some give, but donít know how it might change things on the rocks.

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Re: 4.30 gears interchangeable with 4.37 gears?
« Reply #2 on: Sep 15, 2020, 08:58:13 AM »
It's close enough to not be an issue.
Time to go wheelin!

liveoak

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Re: 4.30 gears interchangeable with 4.37 gears?
« Reply #3 on: Sep 15, 2020, 01:28:17 PM »
I would bite the bullet and put 4:56 in both(as opposed to 4.10) if you have bigger than stock tires or find a pair of used takeout thirds. I guess it depends on how your 4-speed feels now with the 4.37s but I would imagine 4.56 would give a bit of improvement all around.

Gnarly4X

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Re: 4.30 gears interchangeable with 4.37 gears?
« Reply #4 on: Sep 16, 2020, 05:05:57 AM »
Hey everyone, I have a 1980 Toyota 4wd pickup with the stock 1980 only 4.37 differential gears. I blew up the rear end, and need to get it fixed, but 4.37 gears are pretty difficult to find. I was told that 4.30 gears were close enough to work without causing any problems. Is there any truth to that, or am I being fed a line of bs? Thanks!

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Mojavewanderer [OP]

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Re: 4.30 gears interchangeable with 4.37 gears?
« Reply #5 on: Sep 16, 2020, 08:24:44 AM »
Thanks for the replies! Ideally I would definitely re-gear both differentials, but thatís not in the budget right now. Based on your responses, and some other research, I think Iím going to go with the 4.30s. The new 4.30 diff will be in the rear, and 80% of the time it will be in 2 wheel drive, so it should be ok. The truck is on 31 inch tires, right now, and the biggest tire I would put on it would be a 33. The 4 speed does alright right now, itís an old Toyota, so itís slow, but I can get it up to 70 on the freeway if I push it.

Snowtoy

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Re: 4.30 gears interchangeable with 4.37 gears?
« Reply #6 on: Sep 16, 2020, 11:24:12 AM »
With less than a 2% difference between the two, you shouldn't notice the difference on the trail.
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