'87 f250 2wd 5.0 4 speed manual REAR END GEARING
 

Hello everyone, i recently bought this truck and it is the first 4speed i have even driven, 1st gear is granny so i only use 2nd through 4th....but i cannot believe how low geared it is! in 4th gear going 55mph shes absolutely screaming and sounds like its gonna blow up, maybe im just not used to a 4 speed, do you know what the gearing ratio is in my rear end? im assuming everything is stock but cant say for sure....and would i be able just to change the gears in the rear end or the whole rear end itself? i dont want to mess with changing the transmission

sounds to me that the gear ratio in that differential is way too low. that means that truck was made to pull a real heavy load. there should be a metal tag bolted to one of the bolts on the cover and that will tell you what the gear ratio is in the differential. and if it's two wheel drive you can have the gear ratio changed to one that's higher. and to save you some more money in the long run you can get a transmission with over drive in it.

well that makes sense seeming as how the guy i bought it off of sold house trailers and pulled them with this truck, maybe he threw some different gears in it...not too worried about gettin a tranny the truck is just gonna be used for weekend work and huntin/fishin.....thanks for the info though, if he did put different gears in it then the tag will be useless to me wont it? should i go ahead and pull the cover off and count the teeth on the ring gear and pinion to be safe?

he could have bought a used rear end and had it installed or he may have special ordered that gear ratio to be put in for that purpose. 3/4 tons and 1 ton trucks used the same rear ends and could have the gear ratios lowered or raised depending on what the truck is going to be used for. the most common gear ratio for these trucks are the 3:73's that way it offers pulling power with a reasonable power plant. go ahead and do that to see what the ratio is for I'm dying to know myself.

ok well what would be a good ratio to put in it so that im not at 5million rpm's at 55mph

if you can get a hold of a rear end with 3:73 you'll get the best of both pulling power and better fuel mileage like instead of six feet to a gallon of gas to like ten miles to a gallon of gas

great thanks for the info! my buddy just said it might benefit me to get a tranny with OD instead of doing the rear end (like you said), he said it also might be cheaper, what are your thoughs on this? isnt there alot more work and money in replacing a tranny than a rear end? and if i decide to do the tranny instead of the rear end what tranny will be best?

Okay grindman, the tag in my door jam says, trans-A and axle-27......tag on my differential is laid out like this.....V108C
73 10 2 7D03

The "V108C" on your axle tag says that the axle is for a 1985-1986 F-250 with 3:73 gears (Open Differential) and a 10.25" ring gear.

ok well i am very suspicious of that, maybe im just dumb but i dont think there is any way the gears are 3:73....how accurate is it to rotate your tire and count the driveshaft revolutions? i can pull my cover off to count the teeth on my gear if i have to but im just a poor boy and cant afford (wife wont let me put money into the truck) another gasket and gear oil, so im trying to cut corners

and another thing, when i look at aftermarket parts for my truck the year range on everything goes up to 86...skips 87...then starts back at 88 and goes up..........why does no one have parts exactly for a 87, im sure they are interchangeable, just something im curious about

the gears that are in that rear end is what is supposed to be in it. you can still count the teeth on the gears to make sure that is the right ratio, but with the power plant that is in your truck doesn't really make the power that you want. and the only other thing that you might do is put in a five speed to off set the rpms of the engine. the 5.0 doesn't have the power like the 4.9 does either in the old days they used the dana rear ends and were not made for fuel economy they were made for work only. the 87's were the year of the model changes and didn't look the same as the year before and then looked like that for the next four rears until 92 then it happened again. I think the reason why it skips 87 and goes to 88 and up is because of the year model changes and all they did was use the same rear ends that they had left over or the next year they started using the 88's

Ok thanks for all your help

so what tranny should I look for that will be a direct bolt on?

I don't know the model numbers on those transmissions all I know is that if you can find one out of a truck that's a five speed with a 4.9 in it then it will bolt right up because the 5.0 and the 4.9 has the same bolt pattern on the hogs head. on the tail end it may have a slide in yoke and your truck may have the u-joint right at the back of the trans.