NP 205 Speedo Madness

[chefk85]

Ok guys and gals. I have a leak where my speedo cable connects to the tcase with a gear reduction box. 1st is the tcase fluid supposed to be red? is it just transmission fluid? sorry for sounding stupid. 2nd I bought a speedo bullet and new driven gear for a th350(DOH!). after a lengthy search I am having trouble finding good info on this. some say you cant find driven gears for the 205 and I am also unsure how to remove it(lots of buildup. I have tried to remove what I can). I would think its a snap ring of sorts but cant see it. 3rd, maybe 4th, is the bullet/driven gear that I purchased worthless for my application?

thanks in advance,
chefk85

[67swb72klb]

As far as the fluid goes it should have gear lube.. but some do run trans fluid...

[87Skier]

ATF or gear oil... it's been asked several times. The general concensus is to put back in what you took out. It originally came with gear oil, but later new ones received ATF. That started sometime in the late 70's or early 80's.

[kwmech]

More than likely have a seal that needs to be replaced between the trans and transfer. Is the tcase overfull?

[Stocker]

Originally Posted by kwmech

More than likely have a seal that needs to be replaced between the trans and transfer. Is the tcase overfull?

Definitely worth checking. I had gear oil in the t-case. Noticed the transmission kept losing fluid -- then discovered ATF in the (then overfilled) t-case.

[mrein3]

Originally Posted by chefk85

Ok guys and gals. I have a leak where my speedo cable connects to the tcase with a gear reduction box. 1st is the tcase fluid supposed to be red? is it just transmission fluid? sorry for sounding stupid. 2nd I bought a speedo bullet and new driven gear for a th350(DOH!). after a lengthy search I am having trouble finding good info on this. some say you cant find driven gears for the 205 and I am also unsure how to remove it(lots of buildup. I have tried to remove what I can). I would think its a snap ring of sorts but cant see it. 3rd, maybe 4th, is the bullet/driven gear that I purchased worthless for my application?

thanks in advance,
chefk85

If your truck has a NP205, and the diffs have 3.73 gears, and you're running stock height (28") tires, you attach your speedo cable to the t-case and get the correct readings.

If you have 4.11s or 3.07s, you need an adapter. The adapter screws into the t-case. Your speedo cable then screws into the adapter. I have a picture of one on another computer. If somebody doesn't beat me I'll try to post a picture in the next 24 hours.

Regarding what fluid goes in the t-case. I've seen factory literature that says use gear lube and I've seen literature that says use tranny fluid.

The transfer case adapter has seals in the front and the back of it. The seals are similar to the front engine oil seal in the timing chain cover on a small block. And like the front engine oil seal on a small block, the seal eventually cuts a groove in the coupling sleeve or simply dries out and fails.

When I went through mine I decided to use ATF in the t-case so if and when the seal finally dies I wouldn't care. I do NOT want to go through those beasts again.

[mrein3]

Originally Posted by mrein3

If you have 4.11s or 3.07s, you need an adapter. The adapter screws into the t-case. Your speedo cable then screws into the adapter. I have a picture of one on another computer. If somebody doesn't beat me I'll try to post a picture in the next 24 hours.

Better late than never. This is what the adapter looks like. You put one end on the t-case and screw your speed cable in the other.