can someone tell me what a 45 rear axle code means on an 1997 f350

 

I have searched and haven't found a 45 anywhere. Look at the tag on the rear end. The bottom line usually gives you the ratio. Mine is 3L55 which is a 3.55 limited slip. If it was just 3 55 then it would be a 3.55 nonposi rear. Sometimes the first number is real close the the bolt so look carefully.
Jimmy

 

Usually the tag on teh door jam will denote which rearend is on the rig. I think DU means 3.73

 

45 crosses to 4.10 non limited slip.

 

Here's a page that has a lookup chart.

http://www.drivetrain.com/Fordtrkratio_posidata.html

 

Good info, it doesn't mention the 9.75 rear end that most of these trucks come with, but the ratio chart is good!!

 

REAR AXLE RATIO CODES


Also See:
2001 VIN Element Coding Information
&
2002 VIN Element Coding Information



THE FIRST TWO DIGITS OF THE AXLECODE IDENTIFY THE RATIO ANDCAPACITY OF THE REAR AXLE.THE FOLLOWING CHART LISTS THESECODES, THE CORRESPONDING RATIOAND CAPACITY AS WELL AS THEMANUFACTURER'S NAME AND MODELNUMBER.
MANUFACTURER
CODE YEAR RATIO CAPACITY NAME MODEL DESCRIPTION
B2 90/ 4.10 2.77M, 2.95M Ford Limited slip Aerostar
B4 90/ 3.54, 3.73 2.77M, 2.95M, 3.8M, 5.3M, 5.4M, 5.52M Dana (Spicer) 60/61 Limited slip Aerostar (E250, F150/F250), Mexico
B5 90/ 4.10 5.3M Ford Limited slip (F250)
B6 97/ 3.73 3.8M Ford Limited slip (F150-F250, N1)
B7 94 3.31 8.5M Ford Limited slip (F250) Mexico
B9 90/92 3.55 2.77M, 5.3M Ford Limited slip
B9 93/ 3.55 2.95M, 5.3M, 8.5M Ford Limited slip (F250), Aerostar
C2 90/98 4.10 5.3M, 6.34M Dana (Spicer) Limited slip (Econoline)
C3 90/ 3.54 6.34M Dana (Spicer) Limited slip (Econoline)
C4 92/ 3.73, 4.09 5.25M, 6.34M Dana (Spicer) Limited slip (Econoline)
C5 90/96 4.10 6.25M, 6.34M, 8.5M Ford Limited slip (Bronco, "E-F'' Series)
C9 90/ 3.55 6.25M, 6.34M, 8.5M Ford Limited slip (Bronco, "E-F'' Series)
D1 93/ 3.27 3.2M Limited slip (Explorer)
D4 96/02 3.73 2.5M, 2.64M, 3.2M Ford Limited slip (Bronco II, Explorer)
D5 90/96 4.10 7.4M Ford Limited slip (Bronco, "F'' Series)
E2 90/ 4.10 7.8M, 9.75M Dana (Spicer) 70HD Limited slip Econoline, F350
E6 93/ 4.10 7.8M Dana Limited slip (E350)
E8 92/94 4.10 8.5M Dana (Spicer) Regular (Econoline)
E8 94/ 4.88 7.4M Ford Limited slip (F350)
F2 91/ 4.10 8.0M Ford Locking (E350)
F5 90/ 4.10 8.25M Ford Limited slip (F350) Ambulance pkg.
F5 90/94 3.55 2.7M Ford Limited slip
F6 90/ 3.73 2.75M Ford Limited slip (Ranger)
F7 90/ 4.10 2.75M Ford Limited slip (Ranger)
F8 94/ 4.88 8.25M Ford Limited slip (F350)
H4 94 3.54 3.8M Ford Limited slip (F150)
H5 90/94 4.10 3.8M Ford Limited slip (F150,U150)
H7 93/ 3.31 3.8M Ford Limited slip (E150, F150, F250)
H8 91/ 3.08 3.08M, 3.55M Ford Limited slip (E150, F150, U150)
H9 90/ 3.55 3.8M Ford Limited slip (E150, F150)
L9 94 3.55 3.8M Ford Non-limited slip (U150)
R5 91/ 3.55 2.75M Limited slip (Ranger)
R6 91/ 3.73 2.75M Limited slip (Ranger)
W5 90/96 4.10 8.25M Ambulance pkg. wide track rear axles
12 90/ 2.73 3.8M Ford Regular (E150, F150)
14 94/ 3.37, 3.54 3.8M Regular (Windstar)
15 90 3.27 2.95M Ford Non-locking (Aerostar)
16 95/ 3.98 3.0M Regular (Windstar)
18 90/ 3.08 3.8M Ford Non-limited slip (E150, F150, U150))
19 90/ 3.55,3.86,3.79 3.8M Ford Non-limited slip (DM, E150, F150, U150)
22 92/ 4.10 2.95M Ford Non-limited slip Aerostar
23 90/97 3.54 5.3M, 5.4M Dana (Spicer) 60/61 Non-locking (E250)
23 90/95 3.45 2.77M, 2.95M Ford Non-limited slip (Aerostar)
24 90/ 3.73 2.77M, 2.95M, 5.3M, 5.4M, 5.52M Dana (Spicer) 60/61 Non-limited slip (Aerostar, E250)
24 94/ 3.54 3.8M, 5.3M Ford Non-limited slip (F150/F250) Mexico
24 03 3.54 Limited slip (F150)
25 90/96 4.10 5.3M Ford Regular (F250)
25 90/97 3.27,3.73, 2.77M, 2.95M Ford Non-limited slip (Aerostar)
27 94/ 3.31 3.8M, 5.3M Ford Regular (F150/F250) Mexico
29 91/ 3.55 2.95M, 5.3M Ford Non-limited slip (Aerostar, F250)
32 90/ 3.27,4.10 2.95M, 6.34M Dana (Spicer) Non-locking (E250/350)
33 90/ 3.54 6.34M Dana (Spicer) Non-locking (E250/350)
34 90/ 3.73 2.77M, 2.95M, 6.34M Dana Non-limited slip (Aerostar, E250/350)
35 90/92 3.27 2.77M, 2.95M Dana
35 92/ 4.09 5.25M, 5.4M, 6.34M Dana Regular (Econoline)
35 90/ 4.10 6.25M, 8.5M Ford Non-limited slip (F250/350)
39 90/ 3.55 5.25M, 6.25M, 6.34M, 8.5M Dana Non-limited slip (E-F250/350)
41 91/ 3.27 3.2M Ford Non-limited slip (Explorer)
41 99/ 3.73 6.83M Regular (F350)
42 90 3.45 2.64M, 6.64M Ford Regular (Bronco II)
42 96/02 4.10 3.2M, 6.83M Non-limited slip (Explorer, Explorer Sport Trac, F350, Mountaineer)
43 91/95 3.08 3.2M Ford Non-Locking (Explorer/Mountaineer)
43 99/02 4.30 3.2M, 6.83M Non-limited slip (F350, Explorer, Mountaineer)
44 90 3.73 2.64M, 6.64M Ford Regular (Bronco II)
45 90/ 4.10 7.4M Ford Non-limited slip (F350)
45 91/ 3.55 3.2M, 7.4M Ford Non-limited slip (Explorer)
46 93/ 3.73 3.2M Non-limited slip (Explorer)
49 90/ 3.55 7.4M Ford Non-limited slip (F350)
52 90/ 4.10 7.8M Dana (Spicer) 70HD Non-locking (Econoline)
53 90/94 3.54 7.8M Dana (Spicer) Non-locking (Econoline)
56 92/ 4.10 8.0M Dana Regular (E350)
58 92/94 4.10 7.8M Dana (Spicer) Regular (Econoline)
58 94/ 4.88 7.4M Non-limited slip (F350) Mexico, F60 (stripped chassis)
62 90/ 4.10 8.0M Dana Regular (E350)
63 99/ 4.30 8.25M Regular (F350)
65 90/ 4.10 8.25M Ford Non-limited slip (F350) Ambulance pkg.
68 94/ 4.88 8.25M Ford Non-limited slip (F350)
69 90/ 3.55 8.25M Ford Non-limited slip ("F'' Series)
72 90/ 4.63 11M Dana Non-limited slip (F-Super Duty)
73 90/ 5.13 8.25M, 11M Dana Non-limited slip (F-Super Duty) Ambulance pkg. F53 (stripped chassis)
83 90/92 3.08 2.75M Ford Regular (Ranger)
84 90/ 3.45 2.75M Ford Non-limited slip (Ranger)
85 90/92 3.55 2.75M Ford Non-limited slip (Ranger)
86 90/ 3.73 2.75M Ford Non-limited slip (Ranger)
87 90/ 4.10 2.75M Ford Non-limited slip (Ranger)
91 92/ 3.27 2.75M Ford Non-limited slip (Ranger)
92 91/ 3.08 2.75M Ford Non-limited slip (Ranger/Explorer)
95 91/ 3.55 2.75M Ford Non-limited slip (Ranger/Explorer)
96 94/ 3.73 2.75M Ford Non-limited slip (Ranger)

 

If you noticed or not, all 4.10 end in 5. All limited slip start with a letter. All non limited slip start with a number. Axle weight limits go up with the letters or numbers (e.g. B5 is smaller cap. than C5 and 15 is maller than 35). You don't have to know if it is 8.8, 9, 9.75, or 10.25. I look for low gears when buying a truck and have the codes memorized but anything ending in 5 or 6 is 4.10 or 3.73, and a letter before it means LS.

 

Actually this isn't necessarily true. The B6 is a 10.25" rear 3.73 LS unit, and it is found in the F150 7700 and F250LD. With a GAWR well over the stock 8.8 and 9.75 rears, I respectfully disagree that this is a tried and true rule. Other examples are the smaller truck frame based vehicles (Explorer, Ranger, Aerostar). They use many codes in the larger digit range and have a much smaller GAWR than an F150. I do not disagree with the rest of the statement.

-Kerry

 

You are right. I normally do not even look at the small vehicles as I only use F150 up. I did notice the error after I posted. The B6 is a 9 3/4" rear and is also used in Expedition and Navigator. The 10.25" is only in SuperDuty, older F250HD, F350, and E250/350 vans. The 10.25" as far as I know was never used in F150. F250LD I'm not so sure prior to 1997 but LD wasn't full floating then . The 9.75" might have been used in newer Lightning too but I am not positive. I am trying to purchase a 1998 F250LD this week with B6 axle. #7700, 3.73R, LS, 9.75"

I frequently pull cattle trailers or move hay, farm, logging equipment and only buy low geared trucks. This LD will be my lightest truck since '94. Anyway, it wasn't really a rule just a way to distinguish codes and compare them. I admit I'm not always right and I make plenty of mistakes. I'm glad some one reads my threads and pays attention. Keep up the good work. Another article at https://www.ford-trucks.com/articles/axlechart.php

 

Well here's another item to help you Tim. I am the proud owner of a 7700 optioned F150. This truck, as you may know, was the follow on to the F250LD, when they discontinued that model after the '99 model year. Both models do in fact come standard with a 10.25 " semi floating rear axle, not a 9.75", like most 5.4L equipped F150s. The axle tag does identify it as a 10.25" rear. Just look at your odd ball 7 lug wheel covers, 7700's have them too. The 9.75" rears don't, they use common 5 lug axles.

This reminds me of a Chiltons or Haynes manual. If you own a specialty optioned vehicle, these options usually aren't covered in those generalized repair books.

You'll find a few of us F250LD/F150 7700 owners around the site. We like to explain the quirks of these semi-unique trucks.



-Kerry

 

FixitCds.com has cd that covers everything. Ford Sevice manual for one particular year. I only have a 2001 now but can buy a set of several for $60. My Dad has F250 SD PSD 4x4 that came with 7 lug wheel covers but has 8 lug underneath. It has 10 1/4" full floating that I am familar with. Prior to "97 F250LD had 8 lug axles, 10 1/4 semi-floating. I also had 80 F250LD but it had a DANA rear semi-floating. Earlier had 9". I'd like to know more about the LD. I did prefer the HD/SD F250 but I went ahead and bought this 98. It is a fleet truck with an odd baby blue color from Michigan/Missouri. 99 wasn't offered in that color and I haven't found my 98 brochure yet. I can't go pick up the truck until 10/4 because I am too busy at work. Hopefully it will out perform my 90 4x2 F250 HD 5.8L ZF5 4.10 256K and still running strong but the end is near. Thanks for the info.

 

I recall hearing about the 7 lug covers with 8 lugs underneath on a few of the '97 and '98 4x2 LD's. Never heard about the SD's with that, but I don't frequent any message boards about them .
The major complaint for people that want to upgrade the looks of those 7 lug trucks is the odd ball pattern. Hardly anybody makes aftermarket wheels for this lug pattern.

Good luck with the new truck.

-Kerry

 

Looked at used F-150 on dealer lot today. 1997 to 2003 model (lot was closed; sunday) Looked at tag on rear axle. Top line is S (or 5) 52 B. Bottom line is 08 88 9 F 12. By looking at the axle chart referred to in above post, I cannot be sure what the axle ratio is. my best guess is a 3.08 non-positraction. If you can deduce the code please reply.

 

I don't have a decoder for the axle tag, only the door tag. Probably it has 3.08 with the 3 covered by the attaching bolt. My '99 sales brochure lists 3.08, 3.31, 3.55, 3.73 available. Only 3.55 or 3.73 were available as LS. 6 cyl. came as auto with 3.31 or 3.55 or MT w/ 3.08, 3.31, 3.55. 4.6L V8 came with 3.08 or 3.55 in AT or MT. The 3.73 only came with the 5.4L engine. If this is a reg cab long bed 4x2, it can be rated at 5600-6600 lbs. GVWR. The door code should show as 18 or H8 for #3800 lb. payload and H being the LS option. Trailer wts. (bumper pull) 4.2LV6 MT 2300 for RC, 2000 for SC; 4.6LV8 MT 2200 RC, 1900 SC; 4.6LV8 AT 5600 RC, 5300 SC; 5.4LV8 AT (only option, no MT) 6600 RC, 6200 SC. None shown with 4x4. So if you pull much, this would let me want an auto trans and V8. Otherwise you might be posting with others about the Mazda 5 speed problems. My mom gets decent mpg w/ V6 AT SC 4x2 XL with 3.31. This truck should do as well on mpg.