How do i tell what number of gears specks i need for the rear end

No chances are it probably won't you will have to take the rear differential cover off and get the numbers off of the ring gear divide the small number into the big number and it'll tell you what ratio the ring gear and pinion are

Hello Brenda...you will find some identifying information on the actual real axle casing. Stamped numbers, I.D. tag or you can search your VIN (Vehicle Identification Number) or make, model year and series on the internet to see what options were available for rear end gearing ratio's.

Yes you should stick with a similar or identical rear end to ensure proper mounting bracket alignment and gear ratio choices. Dana Model 60, 70 & 80 Axles are not internally identical.

Looks like the standard differential carrier for the E150 is a 8.8" (*10 bolt). Standard, Includes Spider gears, 31 spline, 7/8" shaft.

* Ten Bolt - The rear end cover plate contains 10 mounting plate bolt holes.

You will need to locate the tag on the rear end cover and find out the gear ratio, if theres no tag then you will need the manufactors date on the door, for example 04/05, and also if it got abs, there are three types,4.10 or 3.55 or 3.73. the best way is the tag or pull cover and count the teeth on ring gear and pinion gear and divide the two to get the ratio. goodday, also try to call the dealer parts dept and give them the vin # and they may be able to tell you the type rear end you have,

If you take the VIN # to a GM dealer they should be able to tell you the original rear end that the vehicle came with. If you are going to take the rear end to a shop they will be able to tell when they take it apart. If it is a posi rear end it will have a tag under one af the cover bolts (if it has not been removed) Once inside a posi rear end is immediately identifiable from the clutch pack. Also the number of teeth is stamped on each (pinion and ring) gear. Divide ring gear # by Pinion gear # to get rear end ratio. Didn't get directly to your question, but I hope this helps. Let me know. Thanks

I don't think you can get a rear end that high sped, the best I've ever seen is a 3.2 something . I had that with a 305 and my engine revved higher than 2200 with that. I think you would be better off with a 700R4 transmission from the early-mid 80's. It should bolt on and the overdrive works off an electric/vaccuum switch mounted on the firewall. Hope this helps.

for ten buck you could go to mitchell1diy. do a search

I will assume you are missing your id tag. You will need to remove the rear cover and count the teeth. If you have never opened a drive axle I will warn you it will most certainly stink.

Now to figure the gear ratio:

The best way is to count the teeth on the ring gear and divide by the number of teeth on the pinion gear. Or you can count the number of turns of the pinion it takes to get one full turn of the ring gear.


For example, if we divide a ring gear with 41 teeth by a pinion gear with 10 teeth we find that the gear ratio is 4.10:1 (41/10 = 4.10).

posably but the best way is to open the inspectio cover and count the teeth on the ring gear and pinion gear then devide the first number by the second

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Most auto parts stores can tell you from the tag which rear end you are using and the ratio

The C/Tr: C refers to the colour of the vehicle Tr refers to the interior colour A/TM is your transmission type. None of those numbers identify the rear end ratio.

What you need to do: Since you have to replace the rear end, yank it out. Examine the ring & pinion gears on the differential carrier. Mark on each a starting point, and count the teeth on both the ring & pinion gears. Now, after you have both totals of teeth, divide the # of teeth on the pinion by the number of teeth on the ring gear. Example: 12 teeth on the pinion, 46 teeth on the ring
12/46 = 3.83 ratio