89k5350
1/2 ton status
id go with sm465
CK5
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Weird problem with TH400 (see post #79)
- Thread starter andyblack
- Start date
Not true. An SM465/NP208 combo will bolt directly in place, and use the exact same drive shafts.
Martin
andyblack
Registered Loser
I would really like to put in an SM465 of course, but I got the 400 and good 208 for only $200, plus the kickdown switch and all was included. This is the only vehicle I've ever owned with an auto and I don't care for it at all but I was only in kindergarten when it was made, so I wasn't able to order it like I wanted, if you know what I mean. Haha.
Thanks for the opinions and sharing the experiences though guys. Keep 'em coming. When I get everything back running, I'll post up and tell you how it does. With the stock overdrive auto, I'm getting about 10 mpg. The torque converter isn't locking up anymore. Hopefully I won't be getting any worse with the 400.
Thanks for the opinions and sharing the experiences though guys. Keep 'em coming. When I get everything back running, I'll post up and tell you how it does. With the stock overdrive auto, I'm getting about 10 mpg. The torque converter isn't locking up anymore. Hopefully I won't be getting any worse with the 400.
It is hard to say which tranny is "correct" for any truck in a way,when each of us uses our trucks differently and under different road & traffic conditions....here in MA,I can go from one end of the state to the other in a few hours,and I dont usually drive more than about 20 miles a day,and the farthest I'd ever go from home is less than 200 miles if that...so to me "poorer" mpg isn't as big a deal as it would be if I lived in OK,and it was a 20 mile ride just to get a six pack,and its a hundred miles to the next larger city,or to work and back daily..--the "right" tranny for one person wont be good for another !--the fact so many different trannies could be had factory dont make it any easier to choose which is right too--you could get a 3 speed Muncie manual.,a SM465,NV3500 ,NV4500 ,TH350,TH400,and 700R4 or 480LE.automatics...................................................................................................I wouldn't mind having a NV4500 5 speed behind my diesel,but neither of my trucks are worth the expense of buying one and doing the swap!..-I vowed after converting my 72 K5 to a SM465 I'd just buy another truck that HAD one if I wanted another manual,I hated swapping in the pedals and everything behind the crankshaft!.... now that traffic snarls up in gridlock often here,I'd find a manual tiring to drive,and they aren't as easy to use when pushing snow in tight areas either--my left hip and leg get sore fast now,so a manual aint my first choice........................................................................................................the SM 465's are good for rugged use,and are better suited to a C60 dump truck or a bus than a daily driver in my opinion, but I dont care for the wide jumps between gears on them much,I did love the creeper first gear though...and I liked being able to push start my truck if need be,and I do trust a manual more than any automatic...it sucks when an automatic decides to peuke with no prior warning,a manual will go for years even if well worn unless you really whaled on it...I think its hard enough replacing what came out of the truck too ,and sometimes swapping another whole t-case & tranny unit in isn't the best idea,even if you already have them ,its not a "bargain"in the end...even when we had a junkyard with trucks to pick from ,it was always a chore finding that "right" bracket or crossmember,etc....nowadays you could search for weeks just to find one truck of the right vintage with a manual too here,they crushed 90% of them already...not many manual equipped trucks sold here ..I may end up coming across a good later 87 up 700r4 core and either have someone freshen it up or maybe I can score a useable one cheap--....I've been told not to bother rebuilding the original '85 700r4...too many "early design flaws"........................................................................................If I HAD to drive my Suburban to another location,I suppose I could swap in one of the 2wd TH400's or the TH350 I have I know were good when pulled,but I'd have to cob up a driveshaft, and have no 4wd...better than being dead in the water with NO truck though!...
andyblack
Registered Loser
I agree with that. I don't usually drive this thing on many long trips because gas is high already and I don't have to go anywhere but work, which is like 3 miles away.
I do like the old 4 speed granny gear transmissions for off road use, but the long, slow shifter throw can get annoying for driving around town. I had a Dodge W250 with an NP435 (which is pretty similar to an SM465) and I liked the granny gear but didn't like the high rpm it would turn out on the interstate. The super low reverse gear would be good for backing up a trailer. Also is would pop out of third gear if you got off the gas and didn't hold the shifter in place. When the slave cylinder went out, that wasn't too bad to replace, but when I had to change the clutch, I really hated that. What a pain! I actually wished I had an automatic that day.
So now to the guys who've done this kind of swap, what problems did you run into and what suggestions do you have to make the swap easier?
I do like the old 4 speed granny gear transmissions for off road use, but the long, slow shifter throw can get annoying for driving around town. I had a Dodge W250 with an NP435 (which is pretty similar to an SM465) and I liked the granny gear but didn't like the high rpm it would turn out on the interstate. The super low reverse gear would be good for backing up a trailer. Also is would pop out of third gear if you got off the gas and didn't hold the shifter in place. When the slave cylinder went out, that wasn't too bad to replace, but when I had to change the clutch, I really hated that. What a pain! I actually wished I had an automatic that day.
So now to the guys who've done this kind of swap, what problems did you run into and what suggestions do you have to make the swap easier?
While I dont drive far from the house I drive alot of miles all over the county I live in. Im fixing to start a new job Monday so I will be back to riding with the wife everyday so the blazer will set more now. If I had a fulltime job here in the town we live in I would have some stupid high horsepower rig (possibly even diesel) as long as money allowed, on some 42-44 in tires cause it would be how I wanna set it up for wheeling and if I worked in town it wouldnt be driven but about 5 miles a week so that wouldnt matter. LOL. Im contemplating a new to me vehicle tow rig and have found a suburban with a 4 speed manual in it. Ideally I would swap in an NV4500 for pulling and to get the overdrive for better mileage. And if I could afford it it would get probably a cummins motor also. But They wife cant drive a stick so that hurts us there, I have tried to teach her but bless her heart there is just to much stuff going on at once. LOL. So im leaning towards just sticking to automatics for the simple fact if she had to drive it for some reason she could.
andyblack
Registered Loser
Yeah I live so close to work that I don't really care too much about mileage these days. I used to like to drive my truck all around out through the country for a whole day on a Saturday a long time ago before gas got so high, but it's so high now I don't think I would want to drive anything around for fun - even a Prius or something lame like that.
My wife can drive a manual transmission just fine because she has one in her old Jeep, but I don't think I've ever let her drive the truck we're talking about here but about once or twice. One time we were at Arby's in seperate vehicles for some reason and when we were leaving she got a wild hair and decided she wanted to drive my truck home. I reluctantly gave her the keys and next thing I knew, I heard the engine rev way up and the tires squealing and looked over and she was pulling right out in front of somebody and flying through a red light. Sheesh.
On Saturday my dad was nice enough to borrow a trailer and drove the 100 miles to my house and was going to pick my truck up and take it to his house for us to work on it because he has a nice carport (that has about 1" of clearance at the top for my truck) and an engine hoist and all for me to use. So he shows up with the trialer and it was one of those with the stupid rails on the side. I don't know why they make them like that. Well anyway I had measured the truck to see how wide it was the other day, and I don't know if my dumb butt just measured the width at the rear tires or what, but the truck was about 2" or so too wide at the front tires to go on the trailer. I thought about trying to drive up on one of the rails or something, but since it was a borrowed trailer, I didn't want to risk bending anything. I tried airing the tires way up, but that didn't help. I sold the little tires and wheels that came on it a long time ago, so I didn't have anything narrower that I could put on there. So my poor dad had to waste his whole day for nothing and turn around and pull an empty trailer home. Bummer. Oh well.
My wife can drive a manual transmission just fine because she has one in her old Jeep, but I don't think I've ever let her drive the truck we're talking about here but about once or twice. One time we were at Arby's in seperate vehicles for some reason and when we were leaving she got a wild hair and decided she wanted to drive my truck home. I reluctantly gave her the keys and next thing I knew, I heard the engine rev way up and the tires squealing and looked over and she was pulling right out in front of somebody and flying through a red light. Sheesh.
On Saturday my dad was nice enough to borrow a trailer and drove the 100 miles to my house and was going to pick my truck up and take it to his house for us to work on it because he has a nice carport (that has about 1" of clearance at the top for my truck) and an engine hoist and all for me to use. So he shows up with the trialer and it was one of those with the stupid rails on the side. I don't know why they make them like that. Well anyway I had measured the truck to see how wide it was the other day, and I don't know if my dumb butt just measured the width at the rear tires or what, but the truck was about 2" or so too wide at the front tires to go on the trailer. I thought about trying to drive up on one of the rails or something, but since it was a borrowed trailer, I didn't want to risk bending anything. I tried airing the tires way up, but that didn't help. I sold the little tires and wheels that came on it a long time ago, so I didn't have anything narrower that I could put on there. So my poor dad had to waste his whole day for nothing and turn around and pull an empty trailer home. Bummer. Oh well.
andyblack
Registered Loser
Now I've taken the TH400 apart and I've got the rebuild kit and a new vacuum modulator. Next I have to get a torque converter. Does anyone know what the stall speed is on a TH400 that came out of a 6.2 diesel Blazer? I assume it's a bit lower than what the gas version would be. Also what about the regulator? Some guys say they have used the same torque convertor and regulator for this swap with not much difference, but I'd like to know before I put the trans in so I won't have to take it back out later and redo anything.
One more thing - where can I get the plastic cover that goes over the opening under the torque converter? The trans I got was missing it.
One more thing - where can I get the plastic cover that goes over the opening under the torque converter? The trans I got was missing it.
Diesel convertors are about 1100 rpm if you have a stock 350 engine it's better not to use it, it will bog down easy.
With a big block you'll be OK.
The regulator you mention is called a governor, and yeah you need that changed as well if you have a 350.
And last but not least, there is no plastic cover on the bottom, they are aluminum if they have 3 holes on each side and steel if they are 2 holes on each side.
I have both.
andyblack
Registered Loser
Awesome. I may get a cover from you if I can't find one around here. The trans I have has three holes on each side, so I guess it is aluminum.
I got most of it put together this weekend but when I got the pump cover put on and torqued down, there was about twice as much play at the input shaft (up and down) as there is supposed to be, so I have to get the next size up on the plastic washer that goes between the pump and the clutches.
I still haven't got the torque converter yet. I'm not going to try to use the one that came with it anyway since it was out in the weather and is no good. I've never traded one in before - will they check to see what it came from when I take it in as a core and only give me the exact replacement? I was hoping to take it up there and tell them I wanted a stock converter for a 350. Or did they ever use the TH400 with the 350 engine?
I looked on Summit's website and they listed a lot of different stall speeds to choose from. What is the best speed to use behind a stock to mildly built 350 engine?
Keep in mind that at first I'm going to put it behind the stock 305 just until I can come up with a good 350 to reaplace it. The 305 is shot and has started smoking, but I don't have the funds available right now to replace it too.
I got most of it put together this weekend but when I got the pump cover put on and torqued down, there was about twice as much play at the input shaft (up and down) as there is supposed to be, so I have to get the next size up on the plastic washer that goes between the pump and the clutches.
I still haven't got the torque converter yet. I'm not going to try to use the one that came with it anyway since it was out in the weather and is no good. I've never traded one in before - will they check to see what it came from when I take it in as a core and only give me the exact replacement? I was hoping to take it up there and tell them I wanted a stock converter for a 350. Or did they ever use the TH400 with the 350 engine?
I looked on Summit's website and they listed a lot of different stall speeds to choose from. What is the best speed to use behind a stock to mildly built 350 engine?Keep in mind that at first I'm going to put it behind the stock 305 just until I can come up with a good 350 to reaplace it. The 305 is shot and has started smoking, but I don't have the funds available right now to replace it too.
I'd look for the "correct" diesel torque converter that has the 6 bolts to the flexplate,even if its used and needs to be flushed--others will work,but they may annoy you if the stall speed is too high,it'll feel like it slips when it really isn't slipping....it sucks bad enough taking a tranny out once,why risk having to do it twice??...
Don't get a convertor that is high stall speed, just get a stock replacement, and 305 and 350 get the same TC.Awesome. I may get a cover from you if I can't find one around here. The trans I have has three holes on each side, so I guess it is aluminum.
I got most of it put together this weekend but when I got the pump cover put on and torqued down, there was about twice as much play at the input shaft (up and down) as there is supposed to be, so I have to get the next size up on the plastic washer that goes between the pump and the clutches.
I still haven't got the torque converter yet. I'm not going to try to use the one that came with it anyway since it was out in the weather and is no good. I've never traded one in before - will they check to see what it came from when I take it in as a core and only give me the exact replacement? I was hoping to take it up there and tell them I wanted a stock converter for a 350. Or did they ever use the TH400 with the 350 engine?
Keep in mind that at first I'm going to put it behind the stock 305 just until I can come up with a good 350 to reaplace it. The 305 is shot and has started smoking, but I don't have the funds available right now to replace it too.
And here is a pic of a aluminum cover, look at the spacing and the shape of the trans bellhousing to see if they match.
andyblack
Registered Loser
All right. Thanks for posting that pic. I'll look at the trans real close when I get a chance and see which one I need for sure and then I'll let you know. When I was at the transimission place on Friday, I got the selective washer that I need to go behind the pump and some new washers to go on the pump cover. The washer that came out was the brown one (or C or #3). I got the one that's supposed to be green (D or #4) to replace it. According to my calculations, that should get the play to within spec, which is .003" to .024 I believe. I also got what I guess is a rebuilt stock torque converter. I got a six bolt one because I figured I could use it on the gas engine flywheel or the diesel flywheel if I have to. It's from B&M and the part number is just BM6. I sure hope it works.
There was no stall speed listed on the box. Does anyone happen to know what the stall speed is on a stock TH400? I bought an adjustable vacuum modulator so maybe I can adjust the shifts by turning that little screw inside of it?
Thanks for the help fellas.
There was no stall speed listed on the box. Does anyone happen to know what the stall speed is on a stock TH400? I bought an adjustable vacuum modulator so maybe I can adjust the shifts by turning that little screw inside of it?
Thanks for the help fellas.
andyblack
Registered Loser
Now the transmission has been rebuilt correctly (thanks to my dad). The #3 selective washer for the pump still allowed too much play at the input shaft, so I had to get the #4 size. Should be good to go now. Iceman, I still haven't had a chance to look and see which cover I need to get from you. Another thing I need is a dipstick tube and and a dipstick. I don't know if the dipstick needs to be longer because of the extra deep pan that's on this trans or not. I assume that the diesel versions got a deeper pan than the gas ones. Who knows? 
The deeper pans just add capacity. You still want the fluid at the same level.
Martin
Martin
just as I replied to you in the pm^^^
andyblack
Registered Loser
Hopefully my parts are on the way soon and the TH400 will be going in this weekend.
Now I need to know about the kickdown switch. I was able to get the switch and the bracket and connector from under the dash and the connector that goes to the trans. What do I need to do to hook this thing up? 12 volts probably, but how is the factory setup on the trucks that came with the 400 origianally? I want to do it up as stock-like as possible. Is there a fuse or relay or something? There's two wires - which is 12 volts and what is the other one?
Oh yeah, one more question. The NP208 I have in my truck now has been leaking since I got it about a year and a half ago and I can't tell where from. I replaced the front and rear seals when I put it in but it looks like it's leaking from the top somewhere. Is there another hole that needs a seal somewhere? I have another t-case I'm going to use that (hopefully) has no leaks. Is there another place I need to look for leaks besides the obvious front and rear seals?
Now I need to know about the kickdown switch. I was able to get the switch and the bracket and connector from under the dash and the connector that goes to the trans. What do I need to do to hook this thing up? 12 volts probably, but how is the factory setup on the trucks that came with the 400 origianally? I want to do it up as stock-like as possible. Is there a fuse or relay or something? There's two wires - which is 12 volts and what is the other one?
Oh yeah, one more question. The NP208 I have in my truck now has been leaking since I got it about a year and a half ago and I can't tell where from. I replaced the front and rear seals when I put it in but it looks like it's leaking from the top somewhere.
Is there another hole that needs a seal somewhere? I have another t-case I'm going to use that (hopefully) has no leaks. Is there another place I need to look for leaks besides the obvious front and rear seals?
You have a hose hooked up to the breather, right?
Martin
Martin
andyblack
Registered Loser
You mean on the transfer case right? Yeah there's a hose with a valve thing on the end of it. It seems to be leaking from down lower than that though. Now that I have it out, I will look at it really close when I get a chance and try to figure out what's going on.
andyblack
Registered Loser
I was actually able to get a lot done on this during the weekend. Got the transmission and transfer case bolted in. I was surprised at how close of a bolt-in swap this has turned out to be. 
to GM for engineering so much interchangability into its products.
For anyone doing this swap, be aware that the bolts to attach the torque converter to the flywheel are metric on the 700 and standard on the 400. Same goes for the 6 bolts that hold the torque converter cover on.
The driveshafts ended up having about as much spline showing as they did before, believe it or not. One issue I'm having is front driveshaft clearance at the crossmember. The diesel Blazer I got the trans and transfer case out of had the crossmember spaced down with these little steel spacers that are about an inch long. I reused them (after drilling the appropriate holes in the frame), and the driveshaft will clear the crossmember, but only by about 1/16". I think I'm going to have to drop the crossmember again and grind a notch out of it.
The only thing I need at this point to make the trans work is the vacuum pipe thing that goes from the vacuum modulator to the intake manifold.
to GM for engineering so much interchangability into its products.For anyone doing this swap, be aware that the bolts to attach the torque converter to the flywheel are metric on the 700 and standard on the 400. Same goes for the 6 bolts that hold the torque converter cover on.
The driveshafts ended up having about as much spline showing as they did before, believe it or not. One issue I'm having is front driveshaft clearance at the crossmember. The diesel Blazer I got the trans and transfer case out of had the crossmember spaced down with these little steel spacers that are about an inch long. I reused them (after drilling the appropriate holes in the frame), and the driveshaft will clear the crossmember, but only by about 1/16". I think I'm going to have to drop the crossmember again and grind a notch out of it.
The only thing I need at this point to make the trans work is the vacuum pipe thing that goes from the vacuum modulator to the intake manifold.
