3.21/3.23 is by far the most common ratio for any 1/2 ton Dodge truck from the mid '70s through the end of the run in '93.  3.54/3.55 would be the next common but, in my experience, I would say 1 in 20 had 3.55s based on the trucks I have seen and had reason to ID the gear ratio over the years.  3.91s were not an option in all years and are nigh impossible to find.  2.94 was also available in the '70s and early '80s, but I have never seen that ratio in a 9 1/4", just in 2WD trucks with a 8 1/4".

 

I tried some searches for 'rear axle assembly' on www.car-part.com on the 3 different ratios available for an '88 RC 4x4....

3.23: 5 pages of hits
3.55: 3 pages of hits
3.90: 1 page of hits

The data is littered with 'check ratio' and other ratios like 4.10, etc. Not exact science, but gives you some idea.

My '90 RC 4x4 had 3.55.

 

Looking closer, the 3.90s were not available in a 1/2 ton 4WD, at least not in '88.  Earlier years only list the 3.90 for the 9 1/4" HD, which may mean it was only used in some 3/4 ton trucks and 1 ton vans.

 

Well, back to pulling the cover off the front axle to see what matches up for 83 RC, and as suggested earlier, change the fluid

Because right now the fact remains is that when I bought the replacement rear end I didn't check to see what matched up, and when I needed 4WD no go, it engages just fine, but the front goes one way and rear goes another.

So now after I find out what is needed, I'll be looking for another.

More money sunk in this beast.

 

Shopping for diffs and crossing your fingers on what ratio they are is a waste of time.

Looking closer, the 3.90s were not available in a 1/2 ton 4WD, at least not in '88. Earlier years only list the 3.90 for the 9 1/4" HD, which may mean it was only used in some 3/4 ton trucks and 1 ton vans.

I believe car-part.com uses Hollander interchange data, with some model/option 'expansion'. So a ratio option for a few years could show up for the whole 72-93 range. The goal is what works/swaps, not factory model year nuances.

I have a 9-1/4" in 3.90... its supposed to be from a '77, and has the 5x4.5" pattern axles. FWIW, my '90 RC 9-1/4" is a revised, much heavier casting than the '77. I suspect the 4x4 3.9x ratio is 3.92, to match the available Dana 44 set.

 

Hollander is indeed supposed to show options of what may fit, and it's up to the individual to determine if it's the correct part or not.  Most of the time it's very specific, other times it gets a bit loose.  The parts manual lists nothing but 3.23, 3.54 and 4.09 ratios for a D44 in the late '80s.  The 4.09s were only for 3/4 ton 4WDs.  The '90-'93 manual lists those along with a 3.92 ratio for the D44, but the 3.92 is only listed for 1/2 ton and 3/4 ton pickups, not Ramchargers.

The factory ratio for the 9 1/4" in '90-'93 is listed as 3.90.

 

Okay then, let's narrow this down a bit so that my PTSD doesn't have me thrown in the slammer, since I'm 68, combat/infantry/recon Vietnam Vet and am getting a little frustrated at this whole situation.

I have a 1983 RC Prospector 4X4 with a 4-inch lift and 33's all the way around, have had it 5 years and sunk some bucks in it, to make it as best as possible regarding the age and lack of parts availability. I plan to have the front axle looked at Monday, in the mean time, maybe someone can come up with a better opinion based on the VIN number, not that it is going to show much, but the VIN decoder on here doesn't offer a lot.

1B4GW12TODS498797

Thanks much

 

Thank you for your service Sir!!

The VIN likely won't help in this situation.

The only way I know of to determine the ratio of a Dana axle that missing the tag (besides pulling the cover & looking at the R&P) is to try and find the BOM number on the axle tube & look it up in a reference book. But this only works if the R&P have never been swapped to another ratio.

Bucky

 

Thanks Bucky,

I thought it might be a shot in the dark. My front axle is a Dana then? Not sure yet if the tag is missing

Goes in tomorrow for some service looks like I'll find out then.

The 3:21 9.25 in it now is not the correct one.

Stephen

 

Thanks Bucky,

I thought it might be a shot in the dark. My front axle is a Dana then? Not sure yet if the tag is missing

Goes in tomorrow for some service looks like I'll find out then.

The 3:21 9.25 in it now is not the correct one.

Stephen

Not sure if you've seen this chart

 

Yes I think the Dana 44 was the RC/TD front axle for the whole run.

Bucky

 

Yep, just looked and it is not 3:21 ratio up front, so it's something else.

 

The VIN likely won't help in this situation.

Agreed. 20 years ago I was hitting up Dodge dealers to give me an axle ratio (for salvage units I was bidding on). They could not. These were 89-93 cummins trucks, so not even that old at the time.

You can approximate a ratio by carefully comparing the turns it takes of the yoke vs the axle shafts (turning by hand). Otherwise pop the cover and look for the tooth-count stamp, or count the teeth manually.

FWIW, the Dana 44 needs a different carrier for 3.73-/3.92+ whereas the 9-1/4" uses the same one for all ratios 3.21+.

 

From my experience and the 4 trucks I have owned, the 3.54's were most common in 2wd vehicles with the 8 1/4. The 3.23 were also more common in the 80's trucks as well.  My dad's 79 had the 3.54's factory and he swapped them because of breakage for 78 3.54's out of a ramcharger.   

This is just my experience. Of course the hd models should in theory get higher ratios for easy rpm gain on the motors. 

Neil

 

I am a veteran myself. How did you verify that you didn't have 3.23 gears? If you pulled the cover you may see two numbers or an actuall ratio depending if the gear set had been swapped. If it is two numbers 19:40 or just a 19 then a 40 you would decide the 19 into the 40 to determine gear ratio. Take photos of the numbers in the ring gear. Usually they have some part numbers. You can also use brake clean and dry the gear. Mark one on the ring and count them. Then count the number of gears on the pinion.

If your gears are spread far apart one axle goes faster than the other. The slower axle will cause hopping and binding. Are you sure it turned the opposite way?

 

count the teeth and divide ? just an idea.... 

 

Going in the shop this morning for new belts, and some other things, and yes, changing the gear fluid up front.

Thanks fella's for all the input. I will let you know the outcome this afternoon

And just for fun, this is a Helio.

 

must be like sayin Kleenex cause it sure looks like an airo  lol   

 

The elusive matching axles scenario has been revealed, and hear I thought it was something simple, no problem, we'll just do an axle swap...Bingo..!!!

Well, up front we have the Dana 44 3:91 and in back is a open end 9.25 3:21

No wonder the rascal don't want go anywhere in 4WD. That's 7/10ths off from back to front.

And I'm told the 9.25 3:90 Chrysler rear ends are nearly impossible to find.

 

the 9.25 is an easy to set up rear ,what with its adjusting screws , just buy a crush sleeve eliminator kit ..  maybe you could buy a set of gears as cheap as a drum to drum rear .. ? IDK

 

3.90 is older. (I have one from a '77 D100 diesel)
3.92 is newer. Lots of r&p listings on www.car-part.com. Seems to show up in some Ram 1500's and Durangos.

 

You have the axle. Instead of rolling the dice on the condition of a 30 year old axle, why not re gear the one you have. Throw a bearing kit in it and rest easy.