NP205 problem
 

I have a NP205 mated to a TH400 in my Blazer and I am having trouble getting the TC to 'engage' in 2hi and 4hi. I can put the TC into 4lo with the tranny in park, shift into drive and all is fine. When I try to put it 2hi or 4hi I get an awful grinding noise when I put the the tranny into any gear. Any suggestions as what the problem could be? I've checked for loose motion in the linkage but doesn't seem like much if any. The shift rods seem to be engaging the detent pins but the passenger side rod does have some loose motion. the inside rod doesn't have any loose motion. Is there a trick to shifting the 205?

I bough the TC and tranny from a board member and said it had been rebuilt but had sat in his barn for a year or so.

Thanks in advance.

I got an a similar grinding noise in my '69. It has a TH350/NP203 combo. It turned out to be the sprag gear in the tranny had exploded and sent the bearings all over inside the case.

Since I doubt that is your problem, I'd try putting it in gear and then starting the engine. The noises carry through the drive train, so if you can get a brave friend to look under the truck while you shift, it might help determine the source (transmission vs tcase)

Its definetly the transfer case since it engages fine in 4lo and there is no grinding noise with the tranny in gear. It drives and shifts fine when in 4lo. The gear grinding noise starts when I try to put the tc in 4hi or 2hi and shift the tranny from park to any gear. We're thinking that one of the shift rods (rails?) is not lining up with the detents (proper term?). I haven't been able to find an exploded view of the 205 to know exactly what's inside.

I had the same problem with a Turbo 350 203 combo. If the transfercase finds neutral while the transmission is in park and you don't get it in 2 hi and move the auto shifter out of park the gears are going around in the trans and can't mesh to the transfercase. When this happens you have to turn the truck off, shift to park restart and shift into 2 hi BEFORE moving the auto trans shifter, if not you have to start over.
I would check all aspects of the shift mechanism, as mine had the problem until I tightened up the pivot bolt that the linkage works on. :blah: :blah: :blah:
Good luck!

It sounds to me almost as if your range fork is disconnected. I wonder if the shift fork pin was set good during the rebuild? Fork installed in the correct orientation? There is also supposed to be a 'L' shaped end on the range shift rod that rides on the shift rail link and helps it shift into position. Is that still there? I would be tempted to pull the inspection cover on the driver side and see if / how it is shifting into high.

Here's some info. I hope the images are clear enough to read.

more...

71RestoRod -

What manual did that come out of? Thanks so much, exactly what I needed to see!

Is there a chance that since I do not have a front driveshaft installed, that those gears do not have a load on them and causing some of the problem?

This needs to be a sticky! Lots of good info!

I put a TH400 in my truck. I also have an NP205. Mine does the same thing, I just put the tranny in neutral and shift the transfer case. It that doesn't work I just turn off the engine and then shift it. Everything works just fine and I don't worry about it.

Orangeuavol...

I hope it helps. I don't know what manual... I grabbed those images off of a web site quite a few years ago. Sorry, couldn't find or think of the link though, or I would have posted the link!

Resto

Hey guys -found our "problem" (orangeuavol's dad)
http://67-72chevytrucks.com/vboard/s....php3?t=170577