Regear quick help please - Ford Truck Enthusiasts Forums

Notices
1999 - 2003 7.3L Power Stroke Diesel  
Sponsored by:
Sponsored by:

Regear quick help please

Reply

 
 
 
  #1  
Old 07-07-2018, 01:40 PM
abowman
abowman is offline
Senior User
Thread Starter
Join Date: Oct 2012
Location: oregon
Posts: 299
abowman is starting off with a positive reputation.
Regear quick help please

Alrighty, so I tow allot probably just as much as I am empty. I like to go a little faster than I probably should (60-65 mph in 55mph zones and 70-80 on the freeway) I tow my normal 16' tandom with my 4k crawler on it and my 40' gooseneck with two crawlers about 22k total. Now my question I blew my 3.73 rear end up (broke 3 ring gear teeth). I got a 4.30 front and rear end for free (was told they were 3.73) I'm on 35's going to 37's at some point after I buy a lift. My tow tune is 400hp so I have no problems with power, but I don't want my rpm's to go threw the roof at 70-80mph. Anyone running 4.30's with a zf6 that had 3.73's have any imput? I was really looking forward to the rpm drop going to the 37's with 3.73's but towing would kinda suck with that tall of gear.
 
Reply With Quote
  #2  
Old 07-07-2018, 05:50 PM
Handy1
Handy1 is offline
Senior User
Join Date: Jun 2018
Posts: 105
Handy1 is starting off with a positive reputation.
Originally Posted by abowman View Post
Alrighty, so I tow allot probably just as much as I am empty. I like to go a little faster than I probably should (60-65 mph in 55mph zones and 70-80 on the freeway) I tow my normal 16' tandom with my 4k crawler on it and my 40' gooseneck with two crawlers about 22k total. Now my question I blew my 3.73 rear end up (broke 3 ring gear teeth). I got a 4.30 front and rear end for free (was told they were 3.73) I'm on 35's going to 37's at some point after I buy a lift. My tow tune is 400hp so I have no problems with power, but I don't want my rpm's to go threw the roof at 70-80mph. Anyone running 4.30's with a zf6 that had 3.73's have any imput? I was really looking forward to the rpm drop going to the 37's with 3.73's but towing would kinda suck with that tall of gear.
My truck has 4:10's. From factory. When it wasDRW with stock tires I run those speeds when towing. When I changed it to SRW , I found a set of 4:30 differentials and thought that would be to much gear,so I kept looking till I found a rear differential that matched the front 4:10. I ended up putting 35's on the truck,and when towing I wish I would have went with the 4:30's with the taller tires
 
Reply With Quote
  #3  
Old 07-07-2018, 05:59 PM
akcooper9's Avatar
akcooper9
akcooper9 is offline
Senior User
Join Date: Oct 2016
Location: DFW, Texas
Posts: 378
akcooper9 is gaining momentum as a positive member of FTE.
Originally Posted by Handy1 View Post

My truck has 4:10's. From factory. When it wasDRW with stock tires I run those speeds when towing. When I changed it to SRW , I found a set of 4:30 differentials and thought that would be to much gear,so I kept looking till I found a rear differential that matched the front 4:10. I ended up putting 35's on the truck,and when towing I wish I would have went with the 4:30's with the taller tires
What vehicle is the 4.30 coming out of stock?
 
Reply With Quote
  #4  
Old 07-07-2018, 07:48 PM
Handy1
Handy1 is offline
Senior User
Join Date: Jun 2018
Posts: 105
Handy1 is starting off with a positive reputation.
[QUOTE=akcooper9;18075397]What vehicle is the 4.30 coming out of stock?[/QUOTE
Yes it was a stock truck. There is a local junk yard that only deals in ford trucks. I have known him for over 30 years. He said he had just got a truck in and would check the ratio as he thought it might have 4:10's. The tag said 4:30 and he had not seen those gears from factory in all the years he had been parting trucks out,so he pulled the cover and counted the teeth. He said he did some checking and they could be ordered when the truck was new.
 
Reply With Quote
  #5  
Old 07-07-2018, 07:53 PM
Dan V
Dan V is offline
Posting Guru
Join Date: Jun 2013
Location: north of Minneapolis, MN
Posts: 1,897
Dan V has a great reputation on FTE.Dan V has a great reputation on FTE.Dan V has a great reputation on FTE.Dan V has a great reputation on FTE.
Originally Posted by akcooper9 View Post
What vehicle is the 4.30 coming out of stock?
F450........
 
Reply With Quote
  #6  
Old 07-07-2018, 08:45 PM
Handy1
Handy1 is offline
Senior User
Join Date: Jun 2018
Posts: 105
Handy1 is starting off with a positive reputation.
Originally Posted by Dan V View Post
F450........
I don't remember,but it was SRW because that's what I was looking for
 
Reply With Quote
  #7  
Old 07-07-2018, 09:24 PM
abowman
abowman is offline
Senior User
Thread Starter
Join Date: Oct 2012
Location: oregon
Posts: 299
abowman is starting off with a positive reputation.
Thank you for the replies, the axles came from a 450 I have the matching set i got gave to me. Has a rear sway bar too, so now I have sway bars front and rear.

Handy 1 thank you for that, I was wondering how bad the rpm's would jump seems like they don't do to bad being as you can carry those speeds too. There are allot of times I have wished I had a gear a little higher than my third but lower than my 4th when I am at 30k total gross going up some 7%grades 4th won't quite pull but third is wound out at 55-60. I just didn't want to loose my drive ability empty but I think I will love them towing. Also going to 37's in the near future will put me back at stock according to Dr. Google, so that sounds like it would be a good deal all the way around.
 
Reply With Quote
  #8  
Old 07-07-2018, 11:31 PM
'88 E-350
'88 E-350 is offline
Senior User
Join Date: Jul 2010
Location: Los Angeles, Ca.
Posts: 428
'88 E-350 is gaining momentum as a positive member of FTE.
My '99 F-350 4X4 CC SB V-10 had factory 4.30s. They might be as rare as finding a 350 SB, but they exist. It's possible it was a special order truck since I've not heard of another with that combo. I went to 5.13 with 37" tires which put it to about where a 4.10 and stock tires would be. Towing with the 4.30s and 37s sucked, but woulda probably been fine with a warmed up 7.3.

For OP, 4.10 with 37s would be about equivalent to the 3.73 with 35s you have now so your RPM will be a little higher with the 4.30 and 37s, guessing around 100-150 RPM. The little extra gear reduction will compensate for the new tires' extra rotational mass when accelerating.
 
Reply With Quote
  #9  
Old 07-07-2018, 11:50 PM
abowman
abowman is offline
Senior User
Thread Starter
Join Date: Oct 2012
Location: oregon
Posts: 299
abowman is starting off with a positive reputation.
My last powerstroke (00) and current (01) both had 3.73's the (00) was a auto on 37's and towed allot with it but not the loads I do with the (01) and never really had issues with the towing but with some of the loads iv towed with the current truck I could use some extra gearing, I just love the low rpm cruise that my last 7.3 had. Just thought I would see what everyone else had experienced with the 4.30's, my brother's obs (5speed) on 35's is wound tight at 70mph and I just don't want that, dont stockish rpm but another 3-400 on top of stock would be annoying as hell to drive everyday would up that much. For instance 2500rpm at 60-65 I don't think I would do, 2000rpm wouldn't be bad. Currently 1700rpm at 65 ish.
 
Reply With Quote
  #10  
Old 07-08-2018, 08:03 AM
Sous's Avatar
Sous
Sous is online now
Post Fiend
Join Date: May 2014
Location: Lake Hartwell, GA
Posts: 6,259
Sous has a brilliant futureSous has a brilliant futureSous has a brilliant futureSous has a brilliant futureSous has a brilliant futureSous has a brilliant futureSous has a brilliant futureSous has a brilliant futureSous has a brilliant futureSous has a brilliant futureSous has a brilliant future
My stock tire size and 3.73 gear ZF6 truck towed a 12K camper in 5th gear at 2000 RPM and got 12.5 MPG's measured over 1000 miles through mountains and plains.

Just trying to say that 2000 RPM is the happy place for me truck and is a good compromise between available power (versus lugging) and MPG's (versus wound too tight as you say). I would not feel comfortable towing heavy at 1700 RPM, but that is just me.
 
Reply With Quote
  #11  
Old 07-08-2018, 08:43 AM
timmyboy76's Avatar
timmyboy76
timmyboy76 is offline
Post Fiend
Join Date: Sep 2010
Posts: 5,651
timmyboy76 has much to be proud oftimmyboy76 has much to be proud oftimmyboy76 has much to be proud oftimmyboy76 has much to be proud oftimmyboy76 has much to be proud oftimmyboy76 has much to be proud oftimmyboy76 has much to be proud oftimmyboy76 has much to be proud of
Sous..what are you considering 5th gear? L,12345 or..1234(5)6...when i had 3.73 towing 11k, i couldnt keep in 6th on flatland without egt rising let alone there was nothingvin the tank when stomping on pedal..
 
Reply With Quote
  #12  
Old 07-08-2018, 08:55 AM
Sous's Avatar
Sous
Sous is online now
Post Fiend
Join Date: May 2014
Location: Lake Hartwell, GA
Posts: 6,259
Sous has a brilliant futureSous has a brilliant futureSous has a brilliant futureSous has a brilliant futureSous has a brilliant futureSous has a brilliant futureSous has a brilliant futureSous has a brilliant futureSous has a brilliant futureSous has a brilliant futureSous has a brilliant future
Brother Timmy, that is why I should not reply to forums shortly after waking up...

I refer to 5th as L, 12345, which is actually 5th if you do not count "low" as a normal forward gear.

5th gear is what I use 95% of the time when on the interstate or anything above say 55 MPH, even when towing heavy. My truck is happiest there and anything near 55 MPH should be 4th gear. Grades or long rolling inclines are usually 5th for a bit, then down to 4th or 3rd in some cases like in TN or CO mountains. All of that is/was loaded heavy, not unloaded.
 
Reply With Quote
  #13  
Old 07-08-2018, 10:17 AM
Walleye Hunter
Walleye Hunter is online now
Postmaster
Join Date: Mar 2014
Location: Douglassville, PA
Posts: 4,829
Walleye Hunter is a splendid one to beholdWalleye Hunter is a splendid one to beholdWalleye Hunter is a splendid one to beholdWalleye Hunter is a splendid one to beholdWalleye Hunter is a splendid one to beholdWalleye Hunter is a splendid one to behold
Originally Posted by Sous View Post
My stock tire size and 3.73 gear ZF6 truck towed a 12K camper in 5th gear at 2000 RPM and got 12.5 MPG's measured over 1000 miles through mountains and plains.

Just trying to say that 2000 RPM is the happy place for me truck and is a good compromise between available power (versus lugging) and MPG's (versus wound too tight as you say). I would not feel comfortable towing heavy at 1700 RPM, but that is just me.
It's not just you, the engine makes it clear to me that it starts to feel good @2000 RPM's and diesels will run all day at higher RPM's with no issue. Under normal driving conditions mine will drop into OD at around 42 MPH and drop my RPM's down into lugging territory (I don't know exactly what RPM's that comes to) and I will frequently lock out OD in my local trips around home. Mine is live tuned and if I ever send it out to get tweaked I'll try to get OD backed off to more like 50 MPH. And when I hear of someone towing heavy @60 MPH in high gear I know that they are going too slow for that gear unless they have something other than 3.73 gearing.
 
Reply With Quote
  #14  
Old 07-08-2018, 12:44 PM
JOHN2001's Avatar
JOHN2001
JOHN2001 is offline
Postmaster
Join Date: Dec 2010
Location: Temperance, MI
Posts: 4,398
JOHN2001 is a splendid one to beholdJOHN2001 is a splendid one to beholdJOHN2001 is a splendid one to beholdJOHN2001 is a splendid one to beholdJOHN2001 is a splendid one to beholdJOHN2001 is a splendid one to beholdJOHN2001 is a splendid one to beholdJOHN2001 is a splendid one to behold
Without reading any other comments and having done the homework while I was running 3:73s and 38s. 4:30 gears are as close to the same ratio you can get that equate to 3:73s after its all said and done. So 4:30s and run it!
 
Reply With Quote
  #15  
Old 07-08-2018, 01:05 PM
00t444e's Avatar
00t444e
00t444e is online now
Elder User
Join Date: May 2017
Location: Southern OH
Posts: 688
00t444e is gaining momentum as a positive member of FTE.
I have 35s and 3.73s with my ZF6 and I wouldn't want it any lower, I am at 2000-2200 rpm on the highway which is perfect.
 
Reply With Quote

Thread Tools
Search this Thread

Contact Us Archive Advertising Cookie Policy Privacy Statement Terms of Service

We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.