I got 456's put in with a eaton on a 8.8 rear end. The rear end is on a 2001 ford ranger edge with a 4.0 motor. I know the spedo is off because when the governer kicks in at 92 i am only going like 83. Also when it says i am going 75 my rpm's are are like 3200. By the way i have an auto matic transmission. I'm wondering if there is a problem or just with that high gears and 35 inch tires thats my max speed. My overdirve on off button will flash after i drive the the truck for about 10 minutes. It was doing this even before i got gears. i was wondering what that was too. any help guys would be greatly appreiciated.

 

Your rpm gauge shouldn't be off unless there is a problem. Yes there is soething wrong with your OD light, I pretty sure.

4:56 gear= very high rpm at 75mph. So thats normal.

Sounds to me like you ' re a wheelin guy.

EDIt: a chip or dealership can fix your speedo for ya.

 

4.56s/35s shouldn't put you extremely high rpm. I have 35s/manual/4.88s and I spin 3200 @ 86 mph...

 

im about 99.9% sure that the od light flashing means low on tranny fluid.my truck use to flash all the time then i burnt my tranny up looked in the tranny and it was dry.mine use to come on when i was driving hard and wheeling.so check ur tranny fluid.

 

how much does it cost to have the spedo re calibrated

 

spedo recalib costs like 100 bucks at a shop

 

Flashing OD is a transmission problem.

4.56 and 35's with an auto is what I have. What was your original ratio? If it was like 3.73 then you're definitely going to be off quite a bit -- like about the 10% or so you are experiencing.

How do you know what your "real" speed is, and does the 3200 at 75 mean REAL speed or APPARENT speed?

 

Speedo recalc cost me 50 at the local ford dealership.

 

i was orignally at 355's. I am also having some new problems now. my check engine light has came on and it is dieing when i am idoling. It will drop down to like 300 rpms ever like 10 secounds and then sometimes it dies. I cant figure it out.

 

Well the gear change will have nothing to do with your engine dieing while idling.

 

transmission service is like 100-150 at a dealership as well (check for coupons). Seriously consider one if you've never had this service done before. It's alot cheaper than a new transmission.

Might also add a secondary transmission oil cooler as well.

 

I realize the gears wouldn't cause the truck to die. It just sucks having a few problems at once. Instead of making a new thread i was hoping somone might have an idea of what the problem could be. I appreciate the help so far guys.

 

this might have nothing to do with ur problems but i'v found out that the reason my ranger would start to die and then would kinda like a lope? it was cause the check valve on the gas tank was going bad? so we threw the check va;ve outand bent up some hard line and fixed it ... you can also tuine a motor with the hard line now in my fuel cell lol anyway..back to soething that means something to you... 456's with 35's should be good once you get the 35's on there if not i might be missing something?