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Need help - NP208 speedo gear removal (read last post)

496truck said:
Dead giveaway would be the color of the drive gear on the output shaft. If the old t-case has a teal drive gear and the new t-case has a teal drive gear, no need to swap the drive gears. But you can't tell without pulling the driven gear and looking inside first. The driven gears are color coded in a similar way. If they are different colors then you should swap the old to the new if you want it to read correctly. Provided it was correct to start with...
Click to expand...

The old gear on the output shaft is teal (I guess that's what you call it) and the driven gear is black on the old case. I don't know what color the ones on the new one are. Guess I could ask the guy I got it from if he changed them. Do you know where I can get a guide to these color codes?
 
_DSC0703.JPG



Driven gears (700R-4 or 208 transfer case)
-----------------------------------------
teeth Gear color GM part #
34 Green 9774413
35 Orange 9780387
36 Natural 1359270
37 Red 1359271
38 Blue 1359272
39 Brown 1359273
40 Black 1362048, 25513047
41 Yellow 1362195
42 Green 1362049, 25513049
43 Purple 1362196, 25513050
44 Grey 9780470
45 Lt. Blue 9775187

HPIM0535.jpg


Drive Gears
-----------
15 Gray
17 Red
18 Blue
19 Yellow

But I think only the Gray and Blue were available for GM 208s. The Dodge 208 had other options, but it is slightly shorter. I think you can make a spacer and use the Dodge gear if that's all you can find.
 
Last edited:
So from the info you've given me, I had 40 teeth on the driven gear (black) and 18 teeth on the drive gear (blue). Now how can I look up what it came with stock? I don't think the speedo gears in either t-case has been changed from stock, but I would like to know. Is there a way to see what the final drive ratio or whatever is without taking the tailhousing off? If not, I'll drain the thing and have a look. Will I be able to see the drive gear with just the tailhousing off? So many questions...
 
Just pull out the little holder for the driven gear and shine a flashlight in there. If the new case has the gray gear, then you would need 33.3 teeth on the driven for the same ratio. So the 34 tooth driven gear would be close. If your speedo was spot on before, I would use the same tooth counts as before, even if it means having to swap the drive gear. That swap is pretty easy out of the vehicle.
 
Blue85 said:
_DSC0703.JPG



Driven gears (700R-4 or 208 transfer case)
-----------------------------------------
teeth Gear color GM part #
34 Green 9774413
35 Orange 9780387
36 Natural 1359270
37 Red 1359271
38 Blue 1359272
39 Brown 1359273
40 Black 1362048, 25513047
41 Yellow 1362195
42 Green 1362049, 25513049
43 Purple 1362196, 25513050
44 Grey 9780470
45 Lt. Blue 9775187

HPIM0535.jpg


Drive Gears
-----------
15 Gray
17 Red
18 Blue
19 Yellow

But I think only the Gray and Blue were available for GM 208s. The Dodge 208 had other options, but it is slightly shorter. I think you can make a spacer and use the Dodge gear if that's all you can find.
Click to expand...

This is good info right there! Now, is there any type of chart using these numbers to correct a speedo that is off? Like when you change axle gears and tire size what speedo gears should be used... That would be the shiznit.
 
496truck said:
This is good info right there! Now, is there any type of chart using these numbers to correct a speedo that is off? Like when you change axle gears and tire size what speedo gears should be used... That would be the shiznit.
Click to expand...
Dude, it's called a ratio...

If you change tire size or gear ratio just make a ratio of the old to the new. This is the same ratio as the old driven gear to the new driven gear. If your gears get lower, you will need more teeth on the driven gear or less on the drive gear. If your tires get bigger, the opposite applies.

Or you can look for one of the online calculators.
 
Thanks Fordum. I just added that site to my favorites for future reference.

I contacted the guy I got the t-case from and asked if he had ever changed the speedo gears and he said no.

Finally got around to putting the thing back in the truck last night. I did like Fastmaxx suggested and just laid on my back and bench pressed it up onto the transmission output shaft and it stayed on there just like he said. I had always either had someone right there to start some bolts while I held it in place or used a tranny jack before because I was scared it would fall off onto my face (which is already ugly enough without a NP208 impression on it) if I let it go with both hands. Of course it rained on me the whole time and there was plenty of dirt around to turn into mud. Temp was about 39 or so. Ideal conditions.

Two things I found out that could be of importance to someone like me who isn't mechanically inclined and is doing this job:
1) Don't try to make it easier by filling up the case with ATF before you attach it to the transmission. The holes for the attachment bolts go all the way through and will let all the fluid drain right out. Of course there is a slight delay so you have plenty of time to pour in about two quarts before you notice it's leaking. An old bath towel will help you soak up all the huge red puddles in your tailgate.
2) Attach the rear driveshaft before filling up with ATF. It will run out here to, but quite a bit slower. If you don't notice the trickle and leave for a while to take a dump or something, you may have to add some when you get back.

I was going to drive that truck to work today but the transmission wouldn't go in gear. I remembered that it drained itself after I took the t-case off. I put in some fluid and it went in gear but was slipping pretty bad and I saw pink foam on the dip stick. Uh oh. Hopefully it just needs a lot more fluid. I only put in about a quart or two. Today I'll let the engine warm up and see how far up on the stick the level is. Automatics are so tricky when it comes to their fluid level. I have a hard time knowing how much ATF to put in them for sure.
 
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