SM465 NP208 Shop or Self Rebuild Questions

[87K5Newbe]

Hello all, i appreciate all the support i have recived in the past here. My 87 Blazer has the SM465 and NP208 both of which need new bearings and seals. I was considering doing this myself.

the 208 leaks like a siv and pops out of 4 wheel if i dont hold the stick back somtime, i think mostly in 4L. the 465 shifts ok, somtimes need to drag the clutch to find reverse and of course it leaks as well. need new drive shafts front and rear as well but that i an easy one to solve for me.

first problem i see is tons of cheap chineese bearing and seal kits on Ebay for both transmssion and transfer case. are there good bearing kits out there. it seems the 208 is pretty easy to rebuild acording to youtube, what say you.
second problem is i have heard the 465 if not done properly will pop out of gear. i have never rebuilt a vehical transmission but i am a capable industrial mechanic.

Does anyone have a manuals or guides on rebuilding both units or a weblink they trust.

is there a recomended shop in the west you would recomend. I am In wyoming. just trying to weigh my options here. should i find used 465 and 208 ship them to a shop or ship mine out to a shop or bite the bullet and try it myself? I really dont want to have to park this beast for several months. love driving this thing when home instead of my 2017 Ram.

Any help is appreciated thanks again.

 

[Bent77]

If you can do industrial machinery maintenance, you can rebuild these

I personally have a Chilton manual with both of these in there. You may consider looking for that, or there are some good YouTube coverage on going through these. How good depends on how you prefer your info and such

You can also contact a local transmission shop and see if they have a kit they suggest for these

 

[87K5Newbe]

Chilton manual I guess that makes sense since those wherre the resourse before the internet. Not alot of transmission shops near me. thanks for that.

 

[dyeager535]

I recall the 465 is a bear to completely disassemble. Something in there needs to be pressed off one of the shafts and as I recall takes a pretty specific driver to do. Not complex if you have access to the stuff to do it. A lot of times YouTube will have videos on doing these rebuilds, I'm sure I've seen a thorough one on someone tearing a 465 down in their garage.

I tore apart my NP241 not that long ago to install a slip yoke eliminator, I assume the 208 is probably just as easy. That one is dead simple, although mine didn't need any parts replaced. Hardest part about disassembly/reassembly for me was getting the case halves to seal properly for some reason. But I got plenty of practice assembling and disassembling lol.

 

[BoondocK5]

You’re going to have to purchase a few gear pullers and probably a shop press to get gears off the shafts in order to replace certain synchro’s ( read most of them), not to mention brass hammers and drifts. I had to build a table with a 6 inch round hole cut in it. In order to stand shafts and gears upright to ease removal and installation.
These are some of the tools I didn’t already have as an automotive mechanic.
There is no magic going on in any of these gear boxes, but, attention to detail is surely important.

 

[87K5Newbe]

If you can do industrial machinery maintenance, you can rebuild these

I personally have a Chilton manual with both of these in there. You may consider looking for that, or there are some good YouTube coverage on going through these. How good depends on how you prefer your info and such

You can also contact a local transmission shop and see if they have a kit they suggest for these

Could you tell me the book number of is no to mech trouble. I did some research on chilton manuals for sm465 and np208 and only found vehicles. Thanks

 

[87K5Newbe]

You’re going to have to purchase a few gear pullers and probably a shop press to get gears off the shafts in order to replace certain synchro’s ( read most of them), not to mention brass hammers and drifts. I had to build a table with a 6 inch round hole cut in it. In order to stand shafts and gears upright to ease removal and installation.
These are some of the tools I didn’t already have as an automotive mechanic.
There is no magic going on in any of these gear boxes, but, attention to detail is surely important.

Press is on my list to get this winter for my newly built shop. I have plenty of brass hamers in my box though.

 

[BoondocK5]

I use “Alldata” which is a subscription service. You subscribe to the exact vehicle you’re working on. There is very complete information in Alldata. It has not left me wanting.

 

[HankScorpio]

Hey! I'm on the other side of the mountain from you.
I rebuilt my SM465 myself, never having done one before. I did the NP205 also. I have not done the NP208. I used an Ebay rebuild kit and it has worked fine for many years now. No problems with jumping out of gear. Weld up your shifter while you are in there and take the slop out. Way better shifter feel.

I have a harbor freight shop press, some random gear pullers and a good set of tools, it was not very hard. I used videos from YouTube to get it done, just downloaded them to a tablet and followed along on the bench.

Here is the video from GebBuilt, there are 3 parts. Follow along, step by step, easy.

 

[Bent77]

Could you tell me the book number of is no to mech trouble. I did some research on chilton manuals for sm465 and np208 and only found vehicles. Thanks

6910
Might be available at the library

Has both the 465 and 208. I’ll post pictures of those pages

 

[Bent77]

208

 

[Bent77]

465

 

[87K5Newbe]

Hey! I'm on the other side of the mountain from you.
I rebuilt my SM465 myself, never having done one before. I did the NP205 also. I have not done the NP208. I used an Ebay rebuild kit and it has worked fine for many years now. No problems with jumping out of gear. Weld up your shifter while you are in there and take the slop out. Way better shifter feel.

I have a harbor freight shop press, some random gear pullers and a good set of tools, it was not very hard. I used videos from YouTube to get it done, just downloaded them to a tablet and followed along on the bench.

Here is the video from GebBuilt, there are 3 parts. Follow along, step by step, easy.

Thank you. Feeling much better about this.

 

[87K5Newbe]

Thank you. Feeling much better about this.

Also not sure what you mean about welding up the shifter but I'll look into it

 

[HankScorpio]

1. The "Ball" is tack welded to the shaft. Check it, the welds can crack and get sloppy. 2.The "Snout" is often 2 piece with a roll pin holding the lower half in. It also wears and gets sloppy, you can weld it together. 3. the "Roll pin seat" can wear and you can put a little weld in there and file the slot back to size. Do all 3 and it makes a huge difference.

 

[imiceman44]

Hello all, i appreciate all the support i have recived in the past here. My 87 Blazer has the SM465 and NP208 both of which need new bearings and seals. I was considering doing this myself.

the 208 leaks like a siv and pops out of 4 wheel if i dont hold the stick back somtime, i think mostly in 4L. the 465 shifts ok, somtimes need to drag the clutch to find reverse and of course it leaks as well. need new drive shafts front and rear as well but that i an easy one to solve for me.

first problem i see is tons of cheap chineese bearing and seal kits on Ebay for both transmssion and transfer case. are there good bearing kits out there. it seems the 208 is pretty easy to rebuild acording to youtube, what say you.
second problem is i have heard the 465 if not done properly will pop out of gear. i have never rebuilt a vehical transmission but i am a capable industrial mechanic.

Does anyone have a manuals or guides on rebuilding both units or a weblink they trust.

is there a recomended shop in the west you would recomend. I am In wyoming. just trying to weigh my options here. should i find used 465 and 208 ship them to a shop or ship mine out to a shop or bite the bullet and try it myself? I really dont want to have to park this beast for several months. love driving this thing when home instead of my 2017 Ram.

Any help is appreciated thanks again.

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Just a heads up, that 208 might need a new shifter fork.
I had the same problem it was leaking and ran low on fluid and ended up popping out of gear, the fork was messed up.

 

[87K5Newbe]

View attachment 514772
1. The "Ball" is tack welded to the shaft. Check it, the welds can crack and get sloppy. 2.The "Snout" is often 2 piece with a roll pin holding the lower half in. It also wears and gets sloppy, you can weld it together. 3. the "Roll pin seat" can wear and you can put a little weld in there and file the slot back to size. Do all 3 and it makes a huge difference.

Nice thank you

Just a heads up, that 208 might need a new shifter fork.
I had the same problem it was leaking and ran low on fluid and ended up popping out of gear, the fork was messed up.

Thanks, when I break it down I'll look for that.

 

[imiceman44]

Nice thank you

Thanks, when I break it down I'll look for that.

Sometimes it's just the wear pads that go out, but after they go out the fork gets worn out fast.
Mine would pop out if I hit the brakes a little hard, the gears literally slide forward from the momentum and disengage

 

[kennyw]

GM service manuals are uploaded here on CK5 for many years. Some manuals for specific transmissions as well. Link is in my signature.

 

[kennyw]

GM Transmission and Transfer Case Technical Manuals

GM Transmission and Transfer Case Technical Manuals Number Title n/a 1973-1984_NP205_Quick_REQ_Parts_Sheets 14003.01-3 GM STG NP208 Transfer Case 17001.11-1A GM STG Turbo Hydramatic 700R4 Automatic Transmission 17021.24 GM GM STG Hydramatic 4L80-E Transmission Electrical Supplement

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