what gears?

97strokerHD · Oct 5, 2014

Filled out sig. Hopefully it shows up.

Swaan · Oct 6, 2014

Are you positive you have 3.55. Because with what you said, 37 " tires and 3.55 should put you at 1700-1800 at your 65mph. Not what your saying.

Sure seems to me like you already have 4:10s not 3:55.

I would just leave it. Those numbers are perty good. !!

mandkole · Oct 6, 2014

^^ I was thinking the same thing--seems like 4.10. You could rotate the tire and count the rotation on the drive shaft.

My FILs 97 2wd auto truck (all stock + downpipe) was changed to 4.10s and it was a pulling machine. RPM was right at about 2200 @ 65. It was far less effort to drive than my truck with 8K+ on the back. I loved that truck.

Swaan · Oct 6, 2014

Yup I've got 4:10 and for towing there the way to go. Keeps u above 2000 in the sweet spot.

97strokerHD · Oct 6, 2014

It might already have 4.10s. I bought the truck with the axle swap done and both axle tags still say 3.55. How do I check by counting driveshaft and tire? The RPMs seemed high to me but it does pretty good for mileage.

rusty1161 · Oct 6, 2014

97strokerHD said:
It might already have 4.10s. I bought the truck with the axle swap done and both axle tags still say 3.55. How do I check by counting driveshaft and tire? The RPMs seemed high to me but it does pretty good for mileage.

Is your speedo accurate? Check it against a GPS.

Rusty

97strokerHD · Oct 7, 2014

I'll definitely check it against GPS. Garbage Mechanic I definitely want to be able to tow when I need to. Want to get it set up now so I don't have to redo it later.

gnxtc2 · Oct 7, 2014

97strokerHD said:
How do I check by counting driveshaft and tire?

- Put a mark on the tire and driveshaft.
- Jack the tire up so you can rotate it.
- Start to make one tire revolution.
- As you are turning the tire, start counting the revolutions the driveshaft made.

1 tire revolution=
- 4.1 turns on the driveshaft - 4.10s
- 3.5 turns on the driveshaft - 3.55s

Billy T.
[email protected]

cbf9703 · Oct 7, 2014

rusty1161 said:
Is your speedo accurate? Check it against a GPS.

Rusty

Do this. None of my speedos are accurate due to lift and tires. I'm off by as much as 8-9 mph according to GPS when my speedo says "70".

gnxtc2 · Oct 7, 2014

You can reprogram the PSOM to read correct. There is a calculation that needs to be done to get the right number that gets entered. Do a search.

Billy T.
[email protected]

m j · Oct 12, 2014

I have 3.55 and a zf5, its a granny gear in the 5:1 range
look at the % change between 1st and 2nd. not meant to be used in regular driving.

what a lot of guys in these threads forget is the OD ratio in the auto is a bit taller then the zf5

Garbage_Mechanic said:
MJ, not in the mood for a pissing match here. I know your in the mood today.

I'm driving a 2002 F250 that came with 4.30's stock. There are plenty of trucks that came with 4.10's too. Yes 3.73 is more common.

As far as 1st being a granny, that depends on the trans, and the set up.

ZF-42 (95 and earlier) no granny gear. 2nd too high for takeoff. Pretty much that way stock, gets worse with bigger tires or higher gearing. With 4.10's and stock tires you CAN take off in 2nd. Add bigger tires or have 3.55's and no second gear launch.

ZF-46 96-97 has a lower first gear but weather it is a granny still depends on a lot. With 4.10's and 31" tires 1st is useless, good for 15ft before shifting. With 33's it is still too low. With 3.55 and 33's it is a good takeoff gear, with 3.55 and 35's it is almost too high.

Garbage_Mechanic · Oct 12, 2014

Do you have a 42 or a 47? If your sig was filled out I wouln't have to ask. If you have a 96 or 97 you are right. What size tire?

m j · Oct 18, 2014

Garbage_Mechanic said:
I'm driving a 2002 F250 that came with 4.30's stock. .

does this truck have a powerstroke?

Garbage_Mechanic · Oct 25, 2014

No it is a V-10 truck, but the point is it is stock and 4.30's were available stock if you look for them.

m j · Oct 25, 2014

okay, find me a f250SD powerstroke with 4.30s and I will buy your 'spotted owl' rare example as relevant.
without that, I think you are bringing up extremely unlikely scenario to be argumentative whilst claiming you dont want a pissing match.
I am on vacation for a week so I have plenty of time for a good pissing match while I relax on the beach in Puerto Vallarta

Garbage_Mechanic · Oct 25, 2014

MJ here is what I stated about the 4.30 gears. My point was that if a guy wanted 4.30's, a V-10 Super Duty rearend would get you 4.30's in the rear without having to buy and set up gears. Yes you would need to swap the front gears or put the whole SD front axle in. I never stated SD PSD trucks came stock with 4.30's My purpose of posting in this thread was to help the OP who obviously doesn't have much experience. What was your purpose of posting MJ?

Garbage_Mechanic said:
Another idea to go with it. Swap in a complete 99-04 rearend with a little machine work and custom wheel studs to run OBS bolt pattern. SD's came with 4.10 and even 4.30 in the V-10 trucks. For the cost of a gear set and install you could be along ways to having rear disc brakes.

old man dave · Oct 26, 2014

Garbage_Mechanic said:
MJ here is what I stated about the 4.30 gears. My point was that if a guy wanted 4.30's, a V-10 Super Duty rearend would get you 4.30's in the rear without having to buy and set up gears. Yes you would need to swap the front gears or put the whole SD front axle in. I never stated SD PSD trucks came stock with 4.30's My purpose of posting in this thread was to help the OP who obviously doesn't have much experience. What was your purpose of posting MJ?

He was demonstrating that being "On Vacation" hasn't improved his reading comprehension or attitude.

Or too much mexican beer?

rusty1161 · Oct 26, 2014

old man dave said:
He was demonstrating that being "On Vacation" hasn't improved his reading comprehension or attitude.

Or too much mexican beer?

:whs:

m j · Oct 26, 2014

lets review. OP has a 97 with zf5. he wants to lower rpm at 65. exactly how does putting 4.30 gears or zf5 42 relate

97strokerHD · Oct 26, 2014

Mj you might want to read the thread again. I brought up 4.30 gears in my first post. It was a bit of a two part question. I was asking about the RPMs because they seemed high to me. I also wanted opinions on what I should do about gears because I don't know where the "sweet spot" for crising rpm on these trucks is. It his is my first powerstroke truck and I'm trying to learn all that I can before I waste money. Also it was clearly stated very early in the thread that the v10 trucks were more likely to have 4.30s. I don't mean to join in on the pissing match going on I just want info so that I can learn and not waste my money.