Happier than I was.....

[dave85]

mieage still has me discouraged, BUT !!!!!!!!

My truck has axle code 39, open 3:55, right?

Yesterday, in the mud, i goosed it a little and the rear end went SIDEWAYS.
So, I got to safe, level mud, gooosed it again, same thing. got out and checked. Both wheels had spun!

Soooooo, I got one wheel on pavement, other in good mud, gave it the throttle and the truck pulled out with NO spinning of the off road tire.

I'VE GOT LIMITED SLIP or something. This was the only thing I didn't really like about my truck.
Trying to contact PO by phone to see if they changed it out.

Anyhow, hope everyone had a good Christmas, Santa was good to me.
Dave

 

[soulpatchfr]

i thought the same thing, Dave - 39 means non-LS... i have the same axle.
i haven't really 'tested it' per se, but i bet Ron (Dog_Catcher) will be along shortly to clear it up. i think he's the one that told me it was an open diff

 

[soulpatchfr]

um - i forgot a couple of things.

mieage still has me discouraged, BUT !!!!!!!!

what kind of mileage are you getting? i guess a little more truck info would help, but i got 18 last fill-up w/ 3.55's

Santa was good to me.

do tell... i hope you meant truck goodies

 

[dave85]

Santa gave......

me the limited slip. 39 is an OPEN differential, but my truck(87) has some kind of positive diff.

I just haven't had time to work on the mileage. It's gotta be timing, IP or something.
My old 85 get 17 plus.
dave

 

[160k87F250]

Man, you'all suck!!!!!!!!!!!!! I only get 11-12 mpg on a good tankful. I, too, have 3.55,limited slip. But I have a c6, plus, I'm a little heavy w/ the rt foot and I do alot of city driving. I did manage 18 mpg on the highway, once. That was the longest, slowest trip I've ever been on.
John

 

[93turbo_animal]

easy way to know for sure is jack both wheels up put tranny in nuetral spin one tire by hand if the other tire spins the same way you have some sort of posi if it spins the opposite way its open

 

[shorthair]

3.55 4x4 also, daily driver 34 round trip stop n go both ways 17-18 avg mt always have to watch that dumb right foot.

 

[Agnem]

Man, you'all suck!!!!!!!!!!!!! I only get 11-12 mpg on a good tankful. I, too, have 3.55,limited slip. But I have a c6, plus, I'm a little heavy w/ the rt foot and I do alot of city driving. I did manage 18 mpg on the highway, once. That was the longest, slowest trip I've ever been on.
John

John, what kind of R's do you turn, and have you tried trips where you keep it below 2 grand? I'll be curious to see how the Moose Stang compares to your rig.

 

[DeepRoots]

2k?
that'd put him at like 45mph.

i've gotten 15.5mpg with a similiar setup, but I cruise at 55mph and am generally slow from the take off. 55mph for me is 2,350rpms

dp

 

[Exekiel69]

2k?
55mph for me is 2,350rpms

dp

Ouch!

 

[Dsl_Dog_Treat]

Ok,
Heard my name being called....ears were a burning.

Dave as this list shows Axle code identification Yes that you should have 3:55 open axle.

Goldie has a 4:10 open axle, but straight holshot I can get dually posi scratch on gravel road. Looks impressive too but ******* drivetrain.
Like Aric said, that is the easiest way to check for L/S axle conversion without opening up the housing.

Welcome to the group.

HEY MEL, Hows about a link into the Faqs section, drivetrain area, for the axle id codes. :draw

 

[highest_vision]

That website still has at least some wrong info. From what I've gathered in the past, it is only relevant to 92 and up (or maybe even newer than that!) models.
Here's some good, factory manual info from early 85 (for Danas):

Code Manufacturer Rating Ratio Notes (jaluhn's, not f/r book)
13    Ford        3750    4.11 Ford 9"???
14    Ford        3750    3.00
16    Ford        3750    3.50
17    Ford        3750    2.47
18    Ford        3750    3.08
19    Ford        3750    3.55
22    Dana        5300    4.10 Dana 60?
23    Dana        5300    3.54
24    Dana        5300    3.73
26    Ford        4050    3.55 Unknown
31    Dana        6250    3.07 Dana 61
32    Dana        6250    4.10
33    Dana        6250    3.54
72    Dana        6300    4.10 Dana 70 3/4 ton
73    Dana        6300    3.54
42    Dana        7400    4.10 D70 Dully???
43    Dana        7400    3.54
52    Dana        7400    4.10 Why not same as above?
53    Dana        7400    3.54
62    Dana        8200    4.10
63    Dana        8200    3.54

L/S axles
H3     Ford        3750   4.10 9"?
H4     Ford        3750   3.00
H6     Ford        3750   3.50
H7     Ford        3750   3.08
H8     Ford        3750   3.55
B2     Dana        5300   4.10 D60?
B3     Dana        5300   3.54
B4     Dana        5300   3.73
C2     Dana        6250   4.10 D61??
C3     Dana        6250   3.54
G2     Dana        6300   4.10 Definetly a D70
G3     Dana        6300   3.54
D2     Dana        7400   4.10
D3     Dana        7400   3.54
Note the similarity between the ls and non l/s codes. The only axle id's I am
 sure of would be g2 being a dana 70-2u, and 31 must be a dana 61. Others
 are strongly suspected based on rating. Confermation would be helpful. Also,
 I beilive the same codes were used at least through much of the 80's.

GCWR Ratings:
Manual Trans:
Engine Rear end ratio GCWR
4.9    2.47           5450
        3.08           6450
        3.50           7800
        3.54           7800
        3.55           7800
        3.73 L.D.     7800
        3.73 H.D.    10000
        4.10           10000

5.0-2 BBl 3.08      6450
             3.54      7800
             3.55      7800
             3.73      7800

5.0-EFI   3.08      6450
             3.54      7800
             3.55      7800
             3.73      7800

5.8         3.50      7800
             3.54      7800
             3.73      7800
             4.10      9000

6.9         3.07     9000
             3.54    13000
             4.10    14000

7.5         3.07    9000
            3.54    11500
            4.10    16000

Note: 3.54 & 4.10 w/ 6.9 add 1000# w/ T-19 wide ratio.


Automatic trans:
4.9 3.08 9000
3.50 10000
3.54 10000
3.55 10000
3.73 10500 - note 2
4.10 - note 1 11000

5.0-Carb 3.50 10000
3.54 10000
3.55 10000
3.73 11000
4.10 11000
4.11 11000

5.0-EFI 3.50 11500
3.54 11500
3.55 11500
3.73 12000
4.10 12500
4.11 12500

5.8-2 BBL 3.50 10000
3.54 10000
3.73 11000
4.10 11000

5.8-4 BBL 3.50 10000 - note 3
3.54 11500
3.73 11500
4.10 12500

6.9 3.07 10500
3.54 12000
4.10 14000

7.5 3.07 12000
3.54 15000
4.10 18500

Notes:
1. Heavy duty engine only - 8500+ gvw
2. 10500# for heavy duty (8500+ gvw) only. Light duty (8500- gvw) 10000#
 gcwr
3. F-150 4x2

Note: Max trailer frontal area is 60 sq ft. Devalue 2% for every 1000ft
 elivation.

Interesting notes: (mine, not the book)
1. 7.5 gcwr is much higher than the 6.9. Is it over rated, or the 6.9
 underrated, or is there really that much differnce in power?
2. Gcwr is idepandant of vehicle type, exept for constrainst based on
 drivetrain avalibility.

Originally posted by jaluhn here.
More in a minute
James

 

[highest_vision]

Here is from late 85, with the Sterling axles listed:

13 Ford 3750 4.11(This is likley a 9")
14 Ford 3750 3.00(9")
16 Ford 3750 3.50(9")
17 Ford 3750 2.47(8.8")
18 Ford 3750 3.08(8.8)
19 Ford 3750 3.55(8.8)
22 Dana 5300 4.10(60 semi float?)
23 Dana 5300 3.54
24 Dana 5300 3.73
25 Ford 5300 4.10(10.25 semi float I'd assume)
26 Ford 4050 3.55(not a clue on this one)
27 Ford 5300 3.73
29 Ford 5300 3.55
31 Dana 6250 3.07(D61)
32 Dana 6250 4.10(D60 FF)
33 Dana 6250 3.54
35 Ford 6250 4.10(10.25 FF, 2.5" brakes)
38 Ford 6250 3.08(didn't think the 10.25 was ever offered this tall)
39 Ford 6250 3.55
72 Dana 6300 4.10(D70 FF SRW 2.5" brakes)
73 Dana 6300 3.54
42 Dana 7400 4.10(D70 FF SRW 3" brakes)
43 Dana 7400 3.54
45 Ford 7400 4.10(10.25 FF, 3" brakes)
49 Ford 7400 3.55
52 Dana 7400 4.10(maybe narrow brake D70 dually?)
53 Dana 7400 3.54
62 Dana 8200 4.10(Wide brake D70 Dually I'd assume)
63 Dana 8200 3.54
65 Ford 8200 4.10(3" brake 10.25 dually)
69 Ford 8200 3.55

Limited Slip:
H3 Ford 3750 4.11
H4 Ford 3750 3.00
H6 Ford 3750 3.50
H8 Ford 3750 3.08
H9 Ford 3750 3.55
B2 Dana 5300 4.10
B3 Dana 5300 3.54
B4 Dana 5300 3.73
B5 Ford 5300 4.10
B7 Ford 5300 3.73
B6 Ford 5300 3.55
C2 Dana 6250 4.10
C3 Dana 6250 3.54
C5 Ford 6250 4.10
C9 Ford 6250 3.55
G2 Dana 6300 4.10
G3 Dana 6300 3.54
D2 Dana 7400 4.10
D3 Dana 7400 3.54
D5 Ford 7400 4.10
E2 Dana 7400 4.10
E5 Ford 8200 4.10
F9 Ford 8250 3.55

Originally posted by 82F100SWB, same thread. I know some of these codes changed at some point. I have a G3, and it is a 3.54 LS. I also have been told that for newer trucks the drivetrain site is right with their ID of 4.30 LS. This also doesn't show 12.
Just the facts, ma'am
James

 

[160k87F250]

John, what kind of R's do you turn, and have you tried trips where you keep it below 2 grand? I'll be curious to see how the Moose Stang compares to your rig.

Mel, I think 2k would put me at 50 mph. Just keeping up on the highway requires 2500-2700 rpms. I'm guessing 65 mph. I cant remember. I know she maxes out at 88 mph or so at 3500 rpms. She was screaming. Had a biker pass me holding hos nose. I was putting out all kinds of smoke. It was funny.
I guess I'll pay attention to this more so on the way down for the IDI ralley. Just hope I can keep up.
John

 

[Agnem]

Well, I should know pretty soon. I put the tags on the Moose Stang last night, so I'm on the road to the inspection station on Friday.

James, your charts are about to become a part of our FAQ.