Hi, I have a 91 Dodge w150 4x4 4speed manual with a 318 carbureted motor (5.2) that I'm thinking of regearing due to destroying rear pinion gears when the u-joint closest to the transmission gave out at 55-60 on the highway. (Didn't put two and two together when I noticed the truck vibration.) My truck has allot of problems and I was going to part it out but just can't bring myself to dismantle the truck (Especially as I have nearly 3,000 into it).


So now it is time to bring this old beast back to life. I was thinking I might want to regear as it already is need of rear gears and it wouldn't be to much harder to change out both the front and rear gears at the same time. I currently am running new all season highway 235/75/r15's and do plan on switching to a more aggressive tire in the future though will likely stick with the same size tire.
I was wondering if their is any gearing better than what it has stock that would give me better highway fuel economy in the mountains yet still let me have fun mudding / possibly small trailer hauling?
Also, are their any other mods I should do to my truck that would help fuel mileage or power or just make it a better truck? I do all work myself and love wrenching.
Also, would anyone know where I could get the rear transmission drive shaft yoke that attaches to my transmission with the clamps that go around the ujoint? I can find the Yoke part but not the clamps that go around the ujoint which I lost when it blew apart.
Thanks! Any thoughts ideas or even stories / experiences of your own truck I would love to hear them!

 

First thing's first:

What gears do you currently have? 3.23's? 3.55 was the deepest factory gear in the half-tons, but if you were running factory (sized) tires, that shouldn't have been a problem. Bad driveline angles can break parts (especially U-joints) quickly, but if you're still at factory ride height, I'm still curious as to why the pinion went bad!

I inherited a Ramcharger with a LOT of problems... and the lift promptly made them worse. Be sure you REALLY are committed to this, before you pour MORE money into it. There's nothing worse than a HALF-done Gen.1 Dodge that you give up on. Because no matter WHAT you've got into it by that point, you'll have $500 worth of scrap metal - at best - when you give up.


HOW much more aggressive? Find your tire/gear calculator (you can Bing it), and plan for that gear NOW. Even if you go with 4.88 gears in your factory axles (that's as deep as you can go!), your manual transmission can be more forgiving with smaller tires. I went 35's on my RC, to whcih the gear calculator spit out "4.31" gear ration as ideal. Well, there tain't no such animal, so do you go up to 4.11 (if it were a daily driver on highways, I'd of gone that direction), or go down to 4.56 (the way I went, as it's NOT a DD, but I have a LOTTA hills & stop signs between me and the "offroad." For those times when I do take it around town, 4.56 helps it get OUT of it's own way... and I'm wishing I'd even gone 4.88!).

Weight will also be a factor as well. Mine is a HEAVY overland/expedition-style vehicle under construction, so deeper gears HELP. If you're going for a desert/pre-runner sorta build, and your truck is LOSING weight, a taller gear may not hurt.


Nope. Gen.1 318 mileage is gonna suck diddly-uck, until the end of time. Mine's even a Magnum... and it STILL sucks.

A better cam would help a bit. New fuel filter, a CAI, and little things like that might help. Honestly, manual hubs will be your biggest improvement, if you still do a LOTTA highway driving with it.

Find a good driveshaft shop, and they can help you with that. There's a local shop to me, that built me a new custom rear driveshaft, and I ditched the flimsy factory 1310 yokes. I eliminated the slipyoke, had a custom Ford-style flange built utilizing a 1350 connector. Double-cardon driveshaft uses a 7290 yoke at the rear!

My driveline excitement is near the end of this thread - https://dodgeforum.com/forum/members...-le-150-a.html - axle re-gear is in there, too.

 

Thanks The War Wagon for all of the info! At this point I really wanted to fix it as a secondary truck/weekend truck but didn't want to do a lift or anything to that extent. I've had it a little over a year now (Got it when I was 16 thinking I would have an awesome truck for everything including getting good fuel mileage, was I ever a nut.) and after a little over $3000 into it I might have gone 70 miles before the drive train gave out (due completely to me). The previous owner contacted me wanting to buy it back (for $1000) and if he wants it I'll let it go for the price. Otherwise I'll start working on fixing it up a little more and replacing my drive line as I have money to do so. Sadly this will be a slow project as I am saving up to buy a newer dodge (Gen II) for a daily driver and am currently laid off and don't know if their will be a job to return to.
Would you by chance know what size gearing my truck would have had stock or how to find out? Seems that would be the root to go as I don't have any plans to build up the truck up for anything particular at the moment and don't see the possibility of having enough money to build the truck up for a long time as of yet.

 

There may still be a tag on the axle itself - beats me as to where it's mounted from the factory, as mine rusted away (popped off, actually - since it's aluminum) sometime ago.

There are two OTHER places - under the hood - where you might be able to find it, though.

If it hasn't baked, flaked, or otherwise torn away, the easiest is the tag under the front lip of the hood. Looks like this (split into 2 pics here, for clarity).





Bottom line - "3.5 axle ratio" (3.55, in reality)

There is also a metal cowl tag on the firewall, that looks like this;





This is the codified essence of your vehicle, but it mostly pertains to paint & trim codes. The truck data plates do NOT work the way the old muscle car data plates in the '60's worked, unfortunately.

But here is your VIN decoder, which may - or may not - reveal your axle.

https://dodgeforum.com/forum/vindecoder.php

This can also help - http://dodgeram.org/tech/specs/VIN_decode-pre94.htm

There may still be a paper data sheet (similar to the dealer window sticker, but more technical) beneath the passenger side front seat. The spring will be holding it against the foam body, so removing it is almost impossible. With flash digital photography though, you may be able to snap some pics though, and examine them at your leisure.

And if all ELSE fails, drop the rear diff cover, and count the splines!!!