47RE concerns, and false axle ratio?

A

AustinM

"...what was that noise?"
Joined
Sep 16, 2015
Messages
6
Hey guys. New here to the website.

Now this is an issue (rather concern) I have been having for a while now since I have owned this truck.

'99 24v 4x4, was bought with 14xxxx from a kid for $1500. Didn't know what he had, it was practically a steal at the time.

The under the hood spec sticker and my VIN both pull up that the truck came stock with a 3.55 rear axle ratio, limited slip. But it definitely does not feel like a 3.55. On the highway with 315/75R/16 Buckshots I turn 2200rpm at 60mph. I hit 90MPH before just bumping the redline, but stop because the truck is screaming at that point. Before I had the buckshots, I had 265/70R/17s, just 3rd gen stock wheels and they also turned very high rpms at highway speeds.

As for the shifting with them, it's very hard to determine. Because with "O/D on", The shift from 3rd to 4th is not noticeable at all. But when I turn O/D, the truck has a VERY noticable shift into 4th, at only 35mph. When I have O/D on or off, it makes no difference in top end. I still turn 2200RPMs at 60, on or off.

I do understand a lifetime could happen in 140k miles, could have swapped front and rear end but I'm not sure.

We have assumed it was just swapped for 4.10s, but it seems too high for 4.10s, probably shorter.

Any of you guys have similar experiences with this?


I knew nothing about the trucks history before I got it, all I know is my dad bought it from a kid for $1500. Clearly he didn't know what he had on his hands, but I can try to find out if he told my dad anything later and update the thread.
 
Sounds to me like you're confusing lockup with OD. It sounds like you don't have OD, not a rear gear problem.
 
oldestof11 said:
Sounds to me like you're confusing lockup with OD. It sounds like you don't have OD, not a rear gear problem.
Click to expand...

I must have. Thanks for the clarification.

Do 47RE's have Four gears and an OD? Because when pressing OD button off the truck shifts four times. But when the OD is supposedly on, its practically seamless. Not near the pull it has going into 4th with OD off.

OD Unit shot? Because The transfer case was shot too when I got the truck. Guys probably got it in a bind, busted 4wd and OD and were lucky 2wd worked. The 4x4 Light stayed on for a long time before it finally died.
 
Last edited:
No they are a 4 speed, 3 gears and od. Some people mistake the lockup in 4th for another gear shift.
 
AustinM said:
I must have. Thanks for the clarification.

Do 47RE's have Four gears and an OD? Because when pressing OD button off the truck shifts four times. But when the OD is supposedly on, its practically seamless. Not near the pull it has going into 4th with OD off.

OD Unit shot? Because The transfer case was shot too when I got the truck. Guys probably got it in a bind, busted 4wd and OD and were lucky 2wd worked. The 4x4 Light stayed on for a long time before it finally died.
Click to expand...

OD off
1,2,3, LU(those are the 3 shifts you feel)
 
zstroken said:
OD off
1,2,3, LU(those are the 3 shifts you feel)
Click to expand...

I'll be damned. Appreciate the response guys. Gonna take it to a guy I know, have him get a new OD Unit in. Gonna run like a scalded dog when she comes out. :)

Thanks!
 
oldestof11 said:
Maybe. Could be something else preventing it from shifting.
Click to expand...

I can drop it by him and have him take a look, tell me what he thinks. My original idea was to bring it to a axle guy and have him tell me what ratio it was but this also seems like a very possible issue.
 
Extremely unlikely the ratio was changed as it would require both axles to be changed and that tends to get get expensive.
 
You can tell the ratio yourself. Jack the back end up and rotate the wheel 1 full turn while counting how many revolutions the drive shaft makes. Drive shaft makes a bit more than 4 revolutions it's 4.10. Drive shaft makes 3.5 turns it's 3.54.
 
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