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SM465 4 speed.. How dissapointed I was

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porterzcustomz
09/16/2007 8:42 AM
Hi, im new here and have been searching all over the internet for information on the SM465. I only herd very good things about it but upon install into my truck I was EXTREAMLY dissapointed in its performance. I have a 1990 Blazer 4×4 with a new Vortec EFI 350 V8. My truck came with an automatic, in general I dislike automatics most all my vehicles have been standards. I have owned countless cars and a few trucks. I enjoy offroading alot. My last favorite truck was my lifted Blazer S10. Anyway heres what I found out. At the time no one told me but apparently the SM465 shifts very slow and shifts are met with resistance. You cannot shift the 465 fast or even at a normal rate as you would on a normal car or small truck. Shifting at high rpm (around 4 or 5 grand)takes even longer and downshifting to a lower gear at high rpm is met with even more resistance from the normal. The tranny does not grind or anything like that but it just shifts very slow. There is about a 2 second delay between gears and it causes the engine rpms to drop and you to loose speed. Shifting this tranny is exactly like shifting a big rig! No one told me when I researched it or bought it so I thought mine was broken. I replaced it with another one to find out the same thing. I was still in denile that they could shift that poorly that I found a guy that had 2 trucks with them already installed and I drove them and it was the same thing!! What is the deal here? Why is there no information letting ppl know that they work like this. If I knew what I do now I would of never taken out my automatic. I am not expecting it to shift like a camero but even my old S10 shifted so much nicer then this thing!!

SnoMan
09/16/2007 10:19 AM
That tranny was designed to take about 465 ft lbs of torque continuously without fail and saw service in MD 2 rated ton trucks with GVW’s of over 30K behind big blocks. It is not nor was it ever design to be a light weight quick shifter. If taching it out and snap shifting is your game then a 465 is not your tranny but if you want a bullet proof tranny that can pull for all it is worth all day long even in granny gear then the 465 is your ticket. It is built for strength not speed of shifting.Also comparing a 150 lbs SM465 to a LD light weight gear box in a S10 is like comparing apples to oranges.

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webby4x4
09/16/2007 11:24 AM
porterzcustomz – SnoMan is exactly right on the money here. The SM465 is one of the finest manual, off-road transmissions on the planet and it is designed to take more abuse, torque and horespower than you can probably throw at it. You’ve got your hands on a real gem here, but as SnoMan pointed out, it’s not a speed-shifting transmission by any stretch of the imagination.First and reverse gears on this tranny do NOT have synchro gears in them, as they are designed for severe duty usage. 2nd, 3rd, and 4th gears do have synchros in them which makes shifting a bit easier, but as you’ve found out, it does take a while to shift.

If you’re really unhappy with it, you may want to consider swapping in an NV-4500 manual transmission, which shifts a bit more quickly and has an overdrive. It should be plenty strong for your ’90 FS Blazer. Be advised though, it’s nearly twice as long as the SM465, which means you’ll have to change both driveshafts and modify the skidplate / mounting brackets.

Rick


porterzcustomz
09/16/2007 1:13 PM
Thank you for your responces. I just don’t understand why someone hasent noted the slow shifting before as I had no idea when I got it. What makes it shift slower? I have never experienced anything like it except on big rigs and oil trucks. I think somone should note that it is a slower shifting tranny when they are deciding on putting it into their rig. I am sure im not alone and other ppl are use to shifting fast not even just speed shifing. Everytime I shift it feels like the tranny is telling me NO I dont really want to. Like if I am mud bogging and im in first going slow and I start to get suck in my S10 I would bang second and get the tires spinning faster but in this case I would have to pause in the middle of it or just keep it in the gear, loosing speed and getting more stuck while I change gears or keep it in first and redline it. So even as one of the best offroad trannys I dont really see it. Its strong but it definatly comes with its drawbacks. If your pulling uphill you want to shift fast to avoid loosing speed for example. I just can’t understand why its not noted in the online reviews of it as I might not of took out the auto for it. Am I the only one that shifts fast or cares about a smooth shift without any resistance? Maybe thats how you guys drive but where I come from we like our power and now and then running thru the gears! If I had a SM465 in my camero I would probably loose to a stock honda =) seconds is what makes a quartermile there is no need for a slow shifting 200lb dyno =)I feel like im driving a school bus =(

webby4x4
09/16/2007 1:26 PM
You’ve hit on a few good points here. However, and please don’t take this wrong, but when someone gets a transmission out of dump truck or full-size 3/4-ton / 1-ton truck, it’s kind of expected.You’re certainly not the only one that cares about smooth and/or fast shifts (obviously), but this transmission was bult for severe duty, not fast shifting. It really was built for big, honkin’ dump trucks and stuff like that. So, like SnoMan said, you’re comparing apples and oranges.

However, I had an SM420 in an ’87 F/S Blazer and this is an older cousin to the SM465. I found that I could cut the shift times in half (or better) by pushing in the clutch about a 1/2 second before I let off the gas. This raised the RPM’s slightly and I could get it to shift pretty darn quickly. It’ll take some getting used to, and some practice, but I could shift it about as quickly as you could ***NORMALLY*** (NOT speed-shift) shift a stick-shift Honda car.

Rick


SnoMan
09/16/2007 1:30 PM
I think you do not quite understand here. It is a very HD wide ratio gear box that was never meant to be shifted quickly (it could live in a school bus for many years) as there is a lot of ma$$ in gears and iders shafts for beef and the wide gear ratios means a very large RPM difference between gears when you tach it up to 5000 RPM and you are not going to synchronize gear/shaft speeds (because of ma$$ and RPM) in a heartbeat with it so stop wishing for it. The NV4500 that replaced it is a little better in that ratios are a bit closer together but it is still no snap shifter either. A LD NV3500 would shift quicker but you would loose granny gear and get a much lighter duty tranny. You need to figure out which is more important, winding it to 5000 RPM for every shift or have a proven sturdy tranny with a granny gear. I drove a SM465 in a 72 GMC P/U for mid 70’s to mid eighties and I was not unhappy with it in the slightest. It ranks as one of the best HD 4 sp manuals ever put in a 4×4.

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porterzcustom
09/16/2007 1:53 PM
Thanks for all the feedback. Maybe my post will help others that are eger to do the swap to understand the difference in shift mannors and at lest expect it as I had no idea. It was really dissapointing when the day I got it installed I saw my friend with a older 2wd chevy with a less powerfull carbed 350 and trying to keep behind him as he powerslid sideways then banged second with another posi slide and I was still trying to get it into second gear while he was chirping third gear leaving me in a could of burning rubber looking like a turtle lol

SnoMan
09/16/2007 2:50 PM

quote:


Originally posted by porterzcustomz
Thanks for all the feedback. Maybe my post will help others that are eger to do the swap to understand the difference in shift mannors and at lest expect it as I had no idea. It was really dissapointing when the day I got it installed I saw my friend with a older 2wd chevy with a less powerfull carbed 350 and trying to keep behind him as he powerslid sideways then banged second with another posi slide and I was still trying to get it into second gear while he was chirping third gear leaving me in a could of burning rubber looking like a turtle lol


Here is a list of some of GM’s trany gear ratios.

[url]http://forum.snoman.com/viewtopic.php?t=153[/url]

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porterzcustom
09/17/2007 3:43 PM
Ohh one more thing I might share on the positive side of the swap. Going from the 700 auto to the SM465 I noticed a very nice driveability change. I have 35″ tires on the truck. With the auto when starting out the truck would rev and make alot of noise but not really go anywhere. The 35’s seemed to bog the engine off the line bad. I live on a hill and backin in my driveway or driving up the hill from a stop the auto would wind up and the TC would not lock. The tranny did not slip or anything like that but the way it put the power to the ground when going slow under a load it felt like I was pulling around a bus. Since the swap now off the line it actually moves good and all that slipping and moaning is in the past! I know the lower gearing of the tranny helped but it was also the way the TC handeled the take off that really bugged me. I can’t stand when autos rev and moan off the line when your taking off under a load in this case the load was caused by the 35’s

porterzcustomz
09/17/2007 3:49 PM
I don’t know how to edit my last reply but I dident mean TC I ment auto tranny. I also wanted to add that in 4 wheel low the gearing almost seems too low especially reverse is amazingly low. I can’t imagine with stock tires how low it would be but im sure you wouldent be able to do more then 2mph at redline in reverse.

SnoMan
09/17/2007 5:38 PM

quote:


Originally posted by porterzcustomz
Ohh one more thing I might share on the positive side of the swap. Going from the 700 auto to the SM465 I noticed a very nice driveability change. I have 35″ tires on the truck. With the auto when starting out the truck would rev and make alot of noise but not really go anywhere. The 35’s seemed to bog the engine off the line bad. I live on a hill and backin in my driveway or driving up the hill from a stop the auto would wind up and the TC would not lock. The tranny did not slip or anything like that but the way it put the power to the ground when going slow under a load it felt like I was pulling around a bus. Since the swap now off the line it actually moves good and all that slipping and moaning is in the past! I know the lower gearing of the tranny helped but it was also the way the TC handeled the take off that really bugged me. I can’t stand when autos rev and moan off the line when your taking off under a load in this case the load was caused by the 35’s


This is why they make deeper axle gear ratios…. for bigger tires. No surprise about tranny straining with stock gear and 35’s. A lot of trannies have bit the dust from wheelers not regearing axles for big tires. Also given that the SM465 was used in trucks that could weight over 20,000 lbs, it has a really deep first and reverse gear to get it going and has helped out your current tall combo of axle ratio and tire size. I might mention that you earlier complained about a friend waxing you in a drag, if you would take time to install 4.56 gears in axles and then just use 2nd, 3rd and forth you would have a different outcome. 30 years ago I had a 72 GMC 3/4 ton 4×4 with 32’s and 4.10’s and the engine warmed a bit and it pulled third gear strongly to about 80 MPH and around 5300 RPM. In daily driving I never used 1st and sometimes never used second either.


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ChevyMan078
09/18/2007 2:10 AM
I have to concour with you SnoMan!!! And I might add this porterzcustomz, your buddy might smoke you on pavement… but try this: Hook a nice sized chain from your rear bumper and his rear bumper, next put your truck in 4Lo,and shift into granny 1st…next, proceed to tow his truck around the block while his tires are spinning against the pavement in the opposite direction. Next, laugh your a s s off till he is crying.

gimmie fuel gimmie fire gimmie that which I desire-James Hetfield *Never give an Irish man good cause for revenge. *Guns dont kill people, but they sure help!! *98% OF AMERICANS SAY ‘OH S**t’ BEFORE GOING IN THE DITCH ON A ICEY ROAD. THE OTHER 2% ARE FROM ALASKA, AND THEY SAY, ‘HOLD MY BEER AND WATCH THIS

SnoMan
09/18/2007 4:39 AM
I tell you what, with my old 72 GMC, I cannot ever remember ever needing to use 4 lo for power. The few times I used it was for lo speed crawling over some boulders. First gear high range with 465 provide all the power it aver needed in any scenario. That old 465 was a great tranny when match to my axle ratio and tire size too.

————————– Visit the SnoMan at www.thesnoman.com

porterzcustomz
09/18/2007 11:40 AM
I also wanted to mention that I read somewhere that some ppl have used 50 weight motor oil in the SM465 for quicker shifting idk if its okay to use or not but I am thinking about trying it.

SnoMan
09/18/2007 11:45 AM

quote:


Originally posted by porterzcustomz
I also wanted to mention that I read somewhere that some ppl have used 50 weight motor oil in the SM465 for quicker shifting idk if its okay to use or not but I am thinking about trying it.


You could use 75w90 or straight 80 gear oil but I would not use motor oil.


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webby4x
09/18/2007 9:39 PM
Don’t use motor oil. Gear oil is for gears, as they need an oil with a completely different viscosity. You’ll have more problems in the long run using motor oil.RW

SnoMan
09/19/2007 4:44 AM

quote:


Originally posted by webby4x4
Don’t use motor oil. Gear oil is for gears, as they need an oil with a completely different viscosity. You’ll have more problems in the long run using motor oil.

RW


It is not the viscosity as much as it is the extreme pressure antiwear additives in EP gear oil that this tranny is designed to expect and need. (put motor oil in rear axle and its lack of EP additives would cause ring and pinion to fail quickly even if viscosity was the same.)


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webby4x4
09/19/2007 9:36 PM
Learned something new… ;)What is “EP”?

SnoMan
09/20/2007 4:21 AM

quote:


Originally posted by webby4x4
Learned something new… 😉

What is “EP”?


EP stands for Extreme Pressure. They use a additive (usually something called Zinc Dialkyl Dithio Phosphate or ZDDP) that actually plates the contact surfaces with a antiwear surface when subjected to extreme pressure and heat to prevent metal to metal contact when film ruptures. A modern offset driven hypoid front and rear axles could not possible or survive without it. Also ZDDP has excellent anti rust and anti oxidation properties and it will attack and neutralize rust which makes it great for coating cha$$is bolts and being able to remove that years later even in a corrosive environment. EP gear oil will actually dissolve and loosen rust on a metal part. I have for years sprayed the undersides and plow hardware on my 4×4 plow trucks with used gear oil are a rust preventative in winter salt and it works great! Also sprayed on current cha$$is rust it will penetrate it and stop it.


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