Bronco Forum - Full Size Ford Bronco Forum banner
1 - 20 of 23 Posts

·
Registered
1990 XLT with 92-96 Panels, 351W, 3.55L 8.8 Rear, 6" Lift with Idler Arm Steering, 35" Tires
Joined
·
120 Posts
Discussion Starter · #1 ·
First off, this forum has been awesome. Thanks to the help on here, I have been flying through the repairs on this thing. It took me a lot longer 11 years ago when I first got it. After a few years of neglect, I am bringing it back to its glory days.

I am trying to swap out the speedo drive gear inside the tailshaft of the transfer case. I have seen videos of others and they were able to just pull out a carrier with the gear on it. No such luck with mine. The center post looks like it would allow me to use a gear puller, but I thought I would ask before I break this. How do you remove the drive gear (yellow)?

Vehicle Tire Automotive tire Motor vehicle Hood



Automotive tire Motor vehicle Gear Rim Automotive design
 

·
Man of endless projects
Joined
·
10,389 Posts
from the pic the teeth look ok. is there a reason you are replacing it?

just remeove the 4 bolts on the back of the t-case so you can get to it. it just seals back up with RTV. its not a big deal

there is a wide spring clip in front of the gear that keeps the gear in place. with it removed you can slide the gear forward to remove a ball bearing form the shaft. then you can slide the gear off

 

·
Registered
1990 XLT with 92-96 Panels, 351W, 3.55L 8.8 Rear, 6" Lift with Idler Arm Steering, 35" Tires
Joined
·
120 Posts
Discussion Starter · #3 · (Edited)
is there a reason you are replacing it?
Replacing with one that has more teeth to match up with my 35" tires and 3.55 rear diff. I replaced the driven gear with a 16 tooth. They don't make a 14 tooth that would have matched with the 7 tooth drive gear in the tail shaft. I need to replace both (16 tooth driven, 8 tooth drive) to get my shift points dialed in and get my speedo accurate.

Thanks. The photos in that writeup were helpful.
 

·
Man of endless projects
Joined
·
10,389 Posts
i see. ideally you are suppose to regear the axles. it would help ALOT

17 tooth would be closer

35" rev per mile is about 593
593 x 3.55 axle ratio = 2105
2105 x 8 drive teeth = 16,840
16840 / 1000 = 16.8 driven teeth
 

·
Registered
1990 XLT with 92-96 Panels, 351W, 3.55L 8.8 Rear, 6" Lift with Idler Arm Steering, 35" Tires
Joined
·
120 Posts
Discussion Starter · #5 ·

·
Registered
1990 XLT with 92-96 Panels, 351W, 3.55L 8.8 Rear, 6" Lift with Idler Arm Steering, 35" Tires
Joined
·
120 Posts
Discussion Starter · #6 ·
I asked on another thread but there was a rubber seal and washer on the outside of the yoke before I pulled it off. The rubber seal is about the size of the washer but I don't see it in any assemblies. Do you know if it is needed? Does it go over or under the washer?
 

·
Man of endless projects
Joined
·
10,389 Posts
nahh you over estimate the effects of gearing. technically 4.10 and 35s is about the equivalent to stock 3.55 and 30" tires and would restore 15% of your torque, yet alone 35s being alot heavier

what trans do you have? E4OD or manual? if you have overdrive, you can regear and it will hardly affect highway RPMs. most people run 4.56 and 35s but when you have E4OD, you can go 4.88 or even 5.13 perfectly driveable on highway

i myself run 5.13 on 37s on my bronco and on my F250 i run 33s and 4.56 but might eventually swap it to 5.13 and 35s in the future

is the seal splined? if so it goes on just befor ethe nut to seal the inside of the splines from leaking

Bicycle part Rim Circle Bicycle drivetrain part Auto part


if you have overdrive, you would take the OD ratio and multiply these RPMs by it. for example E4OD has a 0.71 OD ratio.
while the chart says 3029 rpm for 37 and 5.13 gears, when you multiply that by 0.71 i will only be at 2150rpm at 65mph
Colorfulness Slope Rectangle Font Material property
 

·
Registered
1990 XLT with 92-96 Panels, 351W, 3.55L 8.8 Rear, 6" Lift with Idler Arm Steering, 35" Tires
Joined
·
120 Posts
Discussion Starter · #8 ·
is the seal splined?
It wasn't splined. It was just a little rubber seal. I snagged this picture from that thread you sent me. It's that rubber seal under the washer. Looks like it goes back on first from the pics.


Automotive tire Finger Wood Gas Household hardware



what trans do you have?
I have the E4OD. I may do it down the road. The 8 tooth drive gear will give me a good amount of room to change later and only swap my driven gear.

The table is helpful. I probably wouldn't go to 4.10. I always told myself I would go to 4.56 or 4.88 if I ever did it. I used to live in a place that added on a lot of highway miles. Now I get almost no highway miles most of the time. Now it is forest trails and short trips around town. Then you throw in 1 or 2 long road trips a year. May be time to switch it over.
 

·
Registered
1990 XLT with 92-96 Panels, 351W, 3.55L 8.8 Rear, 6" Lift with Idler Arm Steering, 35" Tires
Joined
·
120 Posts
Discussion Starter · #9 ·
@Kingfish999 Where did you run the RTV on this surface before replacing the cover? Stick to the edge but inside the 4 holes?

Automotive tire Wheel Tire Rim Motor vehicle
 

·
Registered
1984, 300 L6, smogless, manual 3speed with overdrive.
Joined
·
2,741 Posts
When I did mine I did outer edge and around the bolt holes.
 
  • Like
Reactions: broncofan22

·
Man of endless projects
Joined
·
10,389 Posts
#3 is the seal

i just smeared RTV on all contact surface of the tail housing. since it does not seal in a round manner

Organism Font Art Motor vehicle Auto part


Rim Aluminium Plastic Metal Fashion accessory


4.56 or 4.88 would be great. 4.56 would be a 28% increase in torque and 4.88 would be a 37% increase
35s and 4.56 gear would have you at 2021rpm @ 65mph while 4.88 would be 2162rpm at 65mph
compared to a non-OD truck like a C6 trans, they would be around 2600-2800 @ 65mph (with converter slippage) from the factory. so no matter what, you would be perfectly driveable. the engine will hold just fine, it was designed to run higher rpm
 

·
Registered
1990 XLT with 92-96 Panels, 351W, 3.55L 8.8 Rear, 6" Lift with Idler Arm Steering, 35" Tires
Joined
·
120 Posts
Discussion Starter · #12 ·
@Kingfish999 This is a great breakdown. My yoke is the flat disk version of #6

Do you have a link to that diagram? I would like to figure out what seal #3 is called or a part number for interchange lookup. #10 looks like the output shaft seal that I picked up, but no idea what #5 is. Maybe that is only for the other yoke. 🤷‍♂️

Lastly there was a ring shaped spring I pulled out with the yoke and output shaft seal. It didn't seem to have a purpose. Basically, when I pulled the yoke, a bunch of pieces came out with it (Washer #2, mini seal #3, and spring ring). #3 is not in this pic. I had already pocket it for the store, which couldn't find one. Any idea what that spring-ring is in the upper left corner?

Automotive tire Wood Bicycle part Rim Auto part
 

·
Registered
1990 XLT with 92-96 Panels, 351W, 3.55L 8.8 Rear, 6" Lift with Idler Arm Steering, 35" Tires
Joined
·
120 Posts
Discussion Starter · #14 · (Edited)
Mystery solved for #5. It is stuck to the yoke. :)

The only thing left is to find a replacement for seal #3 sitting under the washer. I may put the old one in until I find a new one so I can get it back on the road. It looks like it seals the end of the splines when the washer is tightened down on it, although it isn't splined itself.

Automotive tire Wood Tire Font Rim

Automotive tire Wood Rim Automotive wheel system Font
 

·
Registered
1987 Ford Bronco, 460, zf5, JBG HD rear springs, JBG 4” coil, 10.25 rear posi, Dana 44 posi
Joined
·
531 Posts
  • Like
Reactions: broncofan22

·
Registered
1990 XLT with 92-96 Panels, 351W, 3.55L 8.8 Rear, 6" Lift with Idler Arm Steering, 35" Tires
Joined
·
120 Posts
Discussion Starter · #16 ·
You could try finding it from another place that’s just what popped up when I looked up “bw 1356 yoke gasket”
Geez. Thanks for the find. I searched Napa, Oreilly, Rock Auto and some other random transmission site. Not once did I search for "Yoke Gasket". Spline seal, output shaft gasket, etc. I appreciate it. That was driving me crazy
 

·
Registered
1990 XLT with 92-96 Panels, 351W, 3.55L 8.8 Rear, 6" Lift with Idler Arm Steering, 35" Tires
Joined
·
120 Posts
Discussion Starter · #17 · (Edited)
For anyone interested in this same swap...

If you have this same transfer case and are only interested in swapping out this gear, you can cut straight to removing the extension housing after you remove the speed sensor from the top. Removing the output shaft seal wasn't needed. It can be left on the housing and would slide off as a single piece. This makes it a much faster swap as long as you have the oddball sockets (1 1/4) and bits needed (T50). I ended up pressing in the seal with the housing off and on a nice flat surface and slid the entire assembly on over the shaft.

Thanks again for all of the help.
 

·
Registered
1987 Ford Bronco, 460, zf5, JBG HD rear springs, JBG 4” coil, 10.25 rear posi, Dana 44 posi
Joined
·
531 Posts
Yep only reason I knew it was because I was just reading that rebuild thread today and looking for the seal.
 
  • Like
Reactions: broncofan22

·
Man of endless projects
Joined
·
10,389 Posts
i use black RTV on pretty much everything. Ford specified black in the service manuals. however i have now been using Permatex 'Automatic Transmission Sealant' for t-cases after i had the the black RTV start to leak about a year after rebuild. probably not the RTVs fault but since the t-case uses ATF and the sealant says 'for case halfes' i figuered it would be ideal. but for that tail housing you wont have any issues with the high temp.

you dont really NEED the seal. its just easier. if you cannot find it you can put RTV on the splines of the flange and it will do the same job. but it will make it slightly harder to get the flange off next time. this is how alot of rear axles seal the splines from leaking, or how to prevent it anyways

you can buy a whole BW1356 seal kit for pretty cheap so dont spend too much on the seal. or a bearing and seal kit for not much more. it might be worth rebuilding your t-case, even to make sure the pump arm is not wearing through the case
 
1 - 20 of 23 Posts
Top