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1979 f150 4x4
Married transfer case to a C6 transmission.
Can someone help ID what case I have?
And I understand that the fluid inside is ATF, right? And the fluid in the case doesn’t communicate with fluid from the trans, right? Same dex/merc ATF?
How do you drain the transfer case? Do I remove the cover? I’m guessing that plug is the fill hole. And you can see, fluid is leaking past the seal to the driveshaft. Is that Seal the same size and what comes off a divorced transmission?
And what’s the cable for?
The cable is the speedometer cable.
And yes, that hole is a fill hole that doubles as a level indicator. When the fluid drains out it’s full.
I’ll have to go back and look at the pics to see if I can tell you what you have, but there were two different ones available at the time if I’m not mistaken. An NP203 (chain drive, “full-time 4wd”) and an NP205 (gear drive, “part-time 4-WD”) transfer case.
The 203 probably uses ATF but the 205 is usually better off with regular gear oil.
And you are correct that they do not communicate with each other. Transmission fluid stays in the transmission and lubrication for the transfer case stays in the transfer case.
Oh, and it does look like a 203 so probably ATF.
But wait for others to chime in.
Two other potential indicators are your shift lever in the cab and the front hubs.
If you have lockouts in the front hubs it’s either a 205 or the 203 has been converted to part time with a kit.
The 203 shift lever should read high lock, high, neutral, low, and low lock on the **** I believe in that order.
The 205 reads four high, two high, neutral, four low.
But it’s been so long since I looked at mine you better wait for others to confirm that too! :-)
Look at the FRONT of the xfer case for a blue and silver tab with either 203 or 205 stamped on it.
Below NP-205 on left 80/90 gear oil , NP-203 on right with AFT or 50 wt motor oil, or what ever the book says.
Below 203 on left, 205 on right.
Below 203 on left, 205 on right.
205 has a upper ck/fill plug and a lower drain plug on the back side.
Yes cable is for speedometer cable. And I see an elec connector with 90* elbow rubber boot for 4wd indicator. Do you have the blue legend lens light under the dash, to the right of the ash tray?
Other tidbit of info, is 205 is gear to gear drive and is lubed as the gears turn. 203 is chain drive and is "sling lubed", as the chain spins around it slings the lube around, so lock it in and drive in it 4wd a little more often than every winter.
Front axle has manual locking hubs. I’ll need to look at the gear shifter once I lower it from the lift. Does the round cover come off to drain the fluid?
Look at the FRONT of the xfer case for a blue and silver tab with either 203 or 205 stamped on it.
Below NP-205 on left 80/90 gear oil , NP-203 on right with AFT or 50 wt motor oil, or what ever the book says.
Below 203 on left, 205 on right.
Below 203 on left, 205 on right.
205 has a upper ck/fill plug and a lower drain plug on the back side.
Yes cable is for speedometer cable. And I see an elec connector with 90* elbow rubber boot for 4wd indicator. Do you have the blue legend lens light under the dash, to the right of the ash tray?
ok. Thinking it’s a 203. I’ll check for the tag on the front. My shifter looks like the 203 shown and yes I have an indicator under the dash that lights up “locked” when in 4x4
If it's got locking hubs, can the truck be driven with them unlocked without shifting the transfer case to one of the "Loc" positions?
If it can, then it has been converted internally using most likely one of the various conversion kits. If you unlock the hubs and it will not drive until you shift into one of the Loc positions, it has not been converted, or has been put back to stock.
Some people installed locking hubs thinking that was the only difference between full-time and part-time four-wheel drive systems. Did not work that way unfortunately.
Also, using the "cheap" conversions often ended up with prematurely worn parts inside the transfer case. While using the "expensive" kit usually did not have any troubles other than the lighter wallet.
And by today's standards, most would laugh at someone not willing to spend $250 vs $50 to convert to part time. But we just have to remember that this was back when $250 could buy an entire truck!
Nothing wrong with chain driven cases in general. Most, if not all factory transfer cases to this day are chain driven. But the NP203 got a bad rep with some because the chain back then was prone to stretching sooner than expected. Maybe due to abuse with larger tires and ****-poor gearing? Maybe due to not using proper lubricants or changing them at a decent interval? Or just not checking the level often enough perhaps.
Either way, there were some with wide chains and some with narrow, but many had to be changed out at one time or another well under 100k miles.
Haven’t driven it since buying it, only on to the lift. So many issues to sort out first before attempting to take it on the street. I’ll keep the locking stuff in mind but am pretty far away from having it road worthy.
I won a bet once with buddy that was showing me his dad's then brand new '78 (or maybe was a '79?) Ford F-150, I told him if not locked in, if just one wheel was stuck, he was stuck. He pulled the right front tire up on a sheet of ice, I hooked chain to a lamp post, and as I predicted ... it just spun the right front. The "two hots all the way and a bowl with" sure made for a tasty winter lunch from the Texas Inn downtown. Was only across town, took his dad's truck on his gas too.
ok. ended up pulling off the cover and draining the fluid from the transfer case. Definitely not ATF in there. looks actually like motor oil, very dark brown. didn't have the thick viscosity of gear oil, at least not from my limited experience. Will get a new NP203 gasket/seal kit and will start putting things back together. I'll do some research about appropriate lubricant to put in the case. Looks like the front and rear seals need to be replaced as there's a significant amt of wetness on the front and rear driveshafts. Other things I should be resealing/gasketing while I'm tearing things apart? The gasket/seal kit comes w/ lots of stuff that I don't know if I'll need.
What kind of oil goes in 203 transfer case?
New Process NP203 Transfer Case Specs say 10w30 or 30 weight motor oil. New Process 203 Transfer Case Tech: Off-Road.com say "The NP203 uses 10w-40 motor oil. People severely hurt their 203s by using either gear oil (90w) or transmission fluid (18w) in their cases.
Huh, I've read a lot of posts about using 30W oil if operating under 32*F and 50W if not. I've also read not to use multiweighted oils (10w30) as it might foam up too much. I agree, no gear oil. I did read that aluminum cased 203s could use ATF. I'll stick with 30W or 50W motor oil.
The 30 and 50 quotations sound a lot like they were for the earlier Dana model transfer cases, such as the Dana 20 in Broncos, Dana 21 in F100's and perhaps others.
The 30 and 50 quotations sound a lot like they were for the earlier Dana model transfer cases, such as the Dana 20 in Broncos, Dana 21 in F100's and perhaps others.
Paul
i was looking up info for 79 f150s. Seems like there’s no overwhelming consensus
