RPMS at what speeds?

Yeah I wouldn't expect much difference at all between 4.10 and 4.30's, my truck is 4.10's 5spd on 31's and to get the rpm's you're saying I think I'd have to be in the 4.88-5.29 range. Way low gears

 

Even if he had a broken shaft with say a spooled rear end it shouldn't affect RPM, and it would drive like absolute butthole I would think

 

Yeah that makes more sense, for some reason my mind just went to a spool or locker and totally forgot about LSD's

 

I’ll have to check it today after work and make sure that might be the problem idk

 

They’re pretty high in 3rd I’ll be at 40-45 doing like 3500k or 4 rpms and in 4th I’ll be doing 50 at about 3k rpms

 

Look at the tire calculator for your size tires, at the bottom of the page, where it shows RPM and gear ratios

https://www.tacomaworld.com/tirecalc?tires=265-75r16

So you have options to explore..........

1) your final gear is over 5.xx

2) your speedo is reading way low (GPS verified?)

3) your tach is reading way high (you did a cluster swap. But you also say the engine is screaming)

4) you're not in 5th gear

5) there is massive clutch slippage

 

Yea, I doubt it's clutch, he's not complaining about it slipping 1-2 or 2-3. That's where it really shows itself.
Unlikely he got hold of a 5:something matching set of diffs. and not be aware, esp. from a stock donor.
Pretty sure he would know he had another gear if in 4th.

This all leads me to thinking the tach is not reading right.
Is there a click switch behind these to change signal from 4 to 6 cyl.?
OP do you have access to a scanner to verify RPM?

 

A slipping clutch will show itself in the higher gears because in lower gears it’s easier for the engine to move the truck.

 

True, this would be exactly how it would act, but it would smell awful and wouldn't last more then a few minutes if it was being held there slipping while driving.

What's the tach read at idle? Stand on it in neutral till it hits rev limiter and see what it says for RPM, haha not the best approach but it would let you know if it's accurate

 

http://spicerparts.com/calculators/engine-rpm-calculator

 

Nope don’t smell a thing

 

No i don’t think so but i got it off a v6 truck just a auto

 

It reads 1k at idle and idk about hitting rev limiter

 

welp, I'm out, you won't hurt anything trying the top though to see if it 1) bounces around 5500 or 2) goes to 8000, in which case, it's your tach.

If it's not your tach, I guess you have 5:30 gears.

 

Agree. Would be so weird and random to get 5.29 thirds out of a stock donor truck haha.. its gotta be the tach though, I feel like you'd know if you had 5.29's, it'd burn tires through the first three gears

 

Yeah, there may be a compatibility issue between the V6 and 4 cylinder tach.

Can you test the tach against a scan gauge or ultra gauge?

 

But it came off another v6 truck and it did it even with the stock gauge cluster
And I did the GPS Mph and it’s accurate so I think the tach is fine

 

Yeah, the speedo is good but it’s a different signal from the tach.

 

speedometer and tach are driven from two different sources but if it did the same with your old one it doesn't make sense again.

You would really have to check it with a scan. Although if the ECU thinks that what it's spinning I guess everything will always show that way. I guess.

Whatever is going on, to answer your original question, no one else with the exact same set up carries that many revs down the hwy. I carry about 3 grand at close to 80 and mine GPS's correct now with 265/75/16's.

 

Still don’t know gonna check my gear ratio once I get home today