Vannin' Home Forums Dodge Performance (Dodge) Help needed - What Differential do I need

Hi Reed
Srubbed both tags and definitely on 6110 on one and 25 on other, heres a pic of the diff housing and it has 10 bolts on it.


you can see at the 4 o'clock position what I am assuming is the tag with the semicircular top to it under the bolt head.
Regards
Mark

Hmmmm. Well that is definitely a 8 3/8 rear axle, which means you should be able to use just about any pre-1997 8 3/8 rear axle gearset from a Dodge van or truck or from a Jeep. Again, these are more commonly referred to (at least in the States) as an 8 1/4 rear axle.

If you go the Jeep route you have a good chance of finding a limited slip differential as well.

Most of the newer trannys with the 518 come out with 3:55 gears or 3:92's if you are going to tow something larger than a motorcycle trailer or a small boat, you should get the 3:92 but they will use a little more gas than the 3:55. 3:55's will pull 3000 lbs fine but more than that you will need the 3:92. That is the rule I live with on all my trucks and vans. 3:92's just let that engine spin a little faster but it allows it to pull a heavier load easier. Just like riding a ten speed bike uphill. I have a '08 1500 Ram pickup with a 518 in it and I am rated to pull 9000 lbs with 3:92 gears. but realistically speaking you have two choices that will work well. I run 3:55's in the Phoenix in an 8.25 rear end.

Too late to edit my last post so this is an add on. Your rear end looks just like mine which is an 8.25. My tag said 3.54 which for all intents and purposes is 3.55 rear end gears. Here is a pic of mine

My '85 has the 8-3/8 with 3.55 gears according the underhood sticker

My '94 has the 9-1/4 with 3.54 gears.


Either one is fine for your application.

You can get a close aproximation of your present gear ratio by marking one of the rear tires and the driveshaft (a chalk line). Then rotate the tire one complete revolution and count how many times the driveshaft turns. If, for example, the driveshaft turns about 3 1/2 times, it would likely be a 3.55 ratio. 3 1/4 turns, a 3.23 ratio, etc.

As Reed said, look for a 1996 or older donor axle. They all came with 27 spline axles. 1997 and newer have 29 spline axles.

Hi everyone,
Some really useful stuff there indeed, think i will pop the bolt with the tag on first and see if i can make out any further detail as from sounds of it I could be extremely lucky and have a 3.55 but probably not! Pleased theres more than one choice of donor vehicle as american vehicles are fairly rare in our breakers (salvage yards). If i can't make anything out from the tag when its out i'll try the chalk line method and work from there.
Off on vacation for a week in morning so will update when I get back. Thanks all!
Mark