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Salteen
09-04-2020, 07:59 AM
Hello! I cant find much info on this. I want to keep my stock 87 D50 front and rear end. I have no clue what my axel sizes are, what power they can withstand, or what gears can fit them. I know I have a 3.91 ratio, which with my NSG370 and 325/75/15 tires, puts my RPM higher than I like.

I would like to put my truck at 1700-1900 with the tires that are on it.

What gears fit? What power will my axels hold? And what size are my axels?

-Paul

tortron
09-04-2020, 02:08 PM
i have 4.22 lsd rear end out of a 2nd gen truck

generally they have a 3.9

more info here
http://www.mightyram50.net/vbulletin/showwiki.php?title=Rear+Axel+and+Suspension:Gear+R atio

They are not hugely strong.


What wheels are you running? i found i only gained 200rpm at 60mph doing that swap but it feels a lot quicker.
creative tyre diameter may let you live with it till you wanna get some hilux axles under it

B-Line
09-04-2020, 03:14 PM
If you are putting in your v6 then stock is plenty strong.

tortron
09-04-2020, 04:53 PM
Hard launches and burnouts with about 120hp will break factory lsds on 2wds. 200+ you either want a cheap supply of diffs or think about upgrading. 4wd might take more abuse?

Salteen
09-05-2020, 07:28 AM
I want lower cruising rpm so I was thinking on the lines of 3.5-3.75 gearing

I have 15x7 wagon wheels mounted on mud terrain 235/75/LT15 Forecum T08 tires.

I like the look of the truck with the current wheel/tire combo, I dont want to change it.

Do I really have to do an axle swap to get my desired gearing???

tortron
09-05-2020, 12:07 PM
3.545 used in certain 2 wd trucks and 1st Gen 4wd trucks with a MA904 Automatic

I think you might have a hard time finding that

finalfighter
09-05-2020, 06:16 PM
also starion and conquests had the 3.545 gearing with lsd. i cant remember the years but give those a look. i believe the mitsubishi vans had 3.545, dont know for sure.

dancinggecko
09-05-2020, 09:12 PM
There are several other threads on here with info on gearing options, but the responses to this one have pretty well summed it up. 3.909 is by far the most common for 2wd and 4wd trucks. 4.222 is reasonably common in the newer ones, typically the 4x4 trucks with EFI seemed to get more of that gear, but I've seen some of the older 2.6L trucks with that gearing as well. Trucks with 3.545 gears exist, but are not common at all. I think they were only even an option for a couple of years. If you look into some of the first generation Monteros then 4.625 gearing is also an option. When looking for gears it is important to note that the rear end gears are larger than the front. I think the rear is an 8" ring gear and the front are 7.5". I also think the V6 trucks had a beefier rear axle, but I'm not completely sure. I'd have to dig up my factory manual for the specs on that and it is currently in a different state. As long as you aren't abusing it then the stock axle should hold up. 200 hp is only about 50-60 hp more than the stock 3.0L V6 that was an option in these trucks. If you are constantly doing burnouts, hard launches, or otherwise driving it like you stole it then parts are going to break for certain, but drive it with one eye and half sense and it shouldn't be a problem.

Salteen
09-07-2020, 05:25 PM
How about a whole van axle? I stumbled across a gang of 1980's mitsubishi Vans in the junkyard, L series if I'm not mistaken???

Salteen
09-07-2020, 05:27 PM
They just said Mitsubishi Van and Motsubishi wagon, all are complete cars, I'll snag some pics tomorrow, there has to be over 20 of them there