“I Just Got An Amazing Deal One Of The Greatest American Pickup Trucks Ever” I wrote earlier this week after spending under $5000 on a 129,000 mile, four-wheel drive, manual transmission, rust-free GMT400 pickup — a Chevy K1500. Now I’ve owned the truck for a couple of days, and while I love it, I also think that maybe I didn’t get as good of a deal as I thought.
The first thing that got me is something that I didn’t think would be such a huge deal. During my test drive, maybe I did notice there was a bit of input shaft bearing noise when I was off the clutch, but how expensive could a new NV3500 five-speed transmission possibly be? They’re a dime a dozen.
Unfortunately, I was mistaken. It turns out that early the NV3500 only went into GMT400 trucks in 1993; prior to that, these trucks were equipped with a dastardly Getrag five-speed — the 5LM60, also called the HM290.
Transmission Digest — a publication devoted to the transmission repair industry — has a whole page on the HM290/5LM60, and it’s bleak.
“The HM290 was by any standard an extremely complex unit that most technicians considered time consuming and difficult to work on. The unit requires some essential tools, available through Kent-Moore, without which working on it is all but impossible.”
[…]
The 5LM60 …uses the overly complicated and cumbersome four-rail shift design with its myriad number of parts. In 1993 the 5L60 went through further design changes and was designated the New Venture 3500. At long last the four-rail system was scrapped and replaced with a single-rail
Someone on Car Junky automotive forums claims to have been a trained GM transmission technician, and he/she also has very little good to say about the 5L60:
When I received training at the GM training center in Minneapolis in 1991 on this transmission. The training manual (which I still have) refers to it as a 5LM60 Formerly HM-290. At that time I was told the transmission was currently being built by New Venture gear and New Venture Gear is a joint venture between GM (Muncie transmission) and Chrysler (New Process Gear).
In 1987 it was referred to as MG-290 My guess is the G is for Getrag
In 1988 it was referred to as HM-290 HM= Hydramatic / Muncie
In 1989 it was referred to as 5LM60
In 1991 it was referred to as NVG 5LM60 NVG= New Venture GearThere are two designs for the input shaft, input shaft bearings and main shaft bearings. The first design, which documentation will show as 1988-1990, had a ball bearing and a roller bearing behind it. The second design only has a ball bearing but it was a much larger bearing. The first design bearings were more prone to fail. They were failing when these trucks were under warranty with very low miles on them.
There is no way I would suggest fixing your transmission. The bearings are very expensive. Last one I did an estimate on, it was over 2 hundred just for the GM input bearing. The input shafts are different so you can’t put the better bearing in the earlier trans. Also if you take apart the main shaft, many of the parts cannot be reused, and you need an oven and melt sticks to heat the parts to the correct temp for pressing them together during reassembly.
A large holding fixture (special tool) is used to hold everything in position when assembling the transmission.
It is almost always less expensive to replace these transmissions then it is to rebuild them. Even in parts prices alone. It is hard to find good used ones.
But that’s on me; I should have looked at that odometer when I was test-driving the truck, and I should have done a bit more research into the different transmissions of the various K1500 model-years. Alas, it’s my second recent California car-purchase blunder, and while I still don’t think it will lose me any money when I resell, it is a bummer.
The rest of the truck is in good shape. There are a few loose bolts holding the transmission crossmember to the frame, but I’ll just tighten those. The AC leaks at one of its Schrader valves, but I bought a tool to fix that without having to evacuate the refrigerant:
And the headliner is shot:
And the radio makes loads of static
The biggest issue is the odometer (which I can fix easily) and the transmission. If I can get the transmission replaced for a reasonable sum, I honestly won’t care that much about the odometer. Sure, the truck’s value took a hit, but as far as usability, this GMT400’s motor seems healthy, the frame is solid, the body is straight, and pretty much all systems are a-go except the transmission input bearing and the AC.
It’s still a good truck, but just not quite the deal I thought it was.
There are lots of vehicles in this world that have, “the wrong part.” Jeep guys are always trying to avoid the Peugeot BA10/5 manual transmission put in late 80s Jeeps. Many of them will drive fine for a long time until it goes bad. Then it is worth replacing with the, “right,” version for the vehicle, in the case of Jeeps that would be the Aisin AX-15 manual.
I am right now going through the process of replacing the 5 speed manual in my BMW e36. It took a lot of abuse after a seal went bad and leaked all the fluid out. I drive on it and raced it for a few months before realizing it was out of fluid. Even in its damaged state it ran for 2 years and 20,000 miles, making terrible screaming and whaling sounds before just last week it transitioned to sounding like wooden blocks rolling around in the transmission with a bit of vibration. It’s now time to change it out. Amazingly, it never felt different to shift and drives super smoothly.
I feel your pain and I hope you can get some enjoyment out of the truck or get it fixed relatively inexpensively.
I feel like the easiest and likely cheapest option for the trans is simply swapping in a used NV3500. The only complication may be the speedometer hook up. Cable vs. VSS
But I also agree that it will likely go FOR YEARS making this noise. Especially with as little use as it will likely get.
Maybe try some high mileage Lucas Oil Stabilizer in the NV3500?
Not saying that it’s guaranteed to work, but I’ve had more success with Lucas stuff (specifically the oil stabilizer and definitely the power steering stop leak products) on older vehicles. In fact, I had the original GM power steering pump starting to scream at me on my 270,000 express van.. put in the Lucas (expecting no miracles). And it got quieter and quieter, until it sounded normal.
I’m also a cheapskate when it comes to vehicles like this, and I’ve tried most miracles in a bottle. But I’m sure DT’s experimented with that as well, plenty of times lol.
I will say, Seafoam products haven’t done shit in any application I’ve tried.
That’s not the transmission in this particular truck.
the point still remains he could add stabilizer. ????
I swear, some people just want something to argue about or point out someone else’s mistakes.
Referencing that specific element reads as though the commenter couldn’t be bothered with reading past the introduction, missing the crux of the story.
I thought skipping the article in a rush to comment was a bad habit left behind at the old site. Looks like I was mistaken about that.
So you’re saying you didn’t read the article, you simply came straight to the comments? Here, I will explain. Your only reply is to tell the previous commenter that the trans he’s talking about isn’t what is in the truck. OK, SO WHAT? The point of the reply was to say he could put stabilizer in the trans. Regardless of what trans it is, DT could put stabilizer in it. You felt the need to point out the commenter mentioned the wrong trans. Which literally did not matter to the point they were making. And again, you felt the need to reply to me just to argue. Not to make a relevant point.
You have reminded me of some of the most important lessons I’ve learned from decades of being a mechanical engineer; one there are only two kinds of parts, broken ones and ones that haven’t broken yet and two if it wasn’t designed to perform a function for a given lifetime in the design environment, it won’t. Define requirements, propose design to meet requirements, build, test, fix. Worked for me. As long as this vehicle is not the only option to take Enhrn to the birthing center at some future date, just enjoy till it croaks.
Eh, track down a used NV3500, and if it’s no good, then you have a core that probably costs less than $1,000. Problem solved.
Can you just contact the seller and ask point-blank how long the odometer has been disconnected?
Don’t make mountains out of molehills. You have a transmission that makes a little noise under certain conditions. It will probably go on for 100K more miles like that – how much are you actually going to drive this thing? You certainly aren’t going to be commuting in it given what else you own… Drive the thing until it doesn’t move anymore and don’t worry about it. If it sounded like a rock crusher or a siren going down the road and needed three hands to shift I would be nervous, but not with what you have going on. Change the tranny oil more often. Maybe try a little heavier oil since you live in a warm climate. It might not even BE the input bearing, I had a throwout bearing make noise like that in one of my cars. Fixed it when it needed a new clutch anyway.
The odometer? Who cares? It’s an old truck in decent condition that you got for pretty cheap. These things go for a gajillion miles if you can keep them from rotting out, and yours is from the desert. Perfect! Fix the headliner, throw a new stereo with BT in the thing, fix the other minor issues and enjoy the hell out of it.
The Radio is probably the CDM “control data module” fancy term for the actual remote mount tuner, under the dash is prolly failing from bad capacitors. I fixed a buddy of mine’s very clean & original ’90 C1500 with the CDM stole off a Delco CD player radio from an early 90s S-10 I had in some extra parts. Had a broken CD drive as all of them do. If you want to keep it factory look for the least expensive of either another CDM for an ‘88-‘94 or one robbed off of any of the more conventional 1.5 DIN Delco tape or CD units of same vintage that had the rocker switch bass and treble controls. Those also had the same module just mounted on the radio chassis instead of remotely. Swap a couple brackets on and it fits under the dash too.
Of course you can always just mount an aftermarket unit where the cassette player goes and get the aftermarket storage pocket for where the current radio display sits.
Edit, ‘90-‘94. Just remembered ‘88-‘89 had an older style connector for the radio IIRC
They really are decent machines, but not invincible, sadly. I’ve put a fair bit of sweat and money into my K2500, but it’s still an old machine that needs attention. Wouldn’t ever part with it, though!
The radio is a pretty common early GMT problem. My ‘88 did the same thing. As I recall, the amplifier is actually down in the dash somewhere and is prone to failure. I never replaced mine but if memory serves a single-DIN (or double? Don’t recall offhand) replacement will fit and then you can bypass the amplifier altogether.
DT: you need to make a check list (and use it) when you go examine a car for sale.
Yeah, no kidding – I’ve bought plenty of junk vehicles, but I’m not about to spend 5K on anything without being pretty dang careful – and I’m not even a professional car buyer/writer/journalist!
The truth is: I didn’t really care that much. A rust-free 5spd 4×4 Chevy pickup for $4,900 is a solid deal. It’s just not QUITE the deal I thought it was initially.
“Here’s Everything Wrong With My GMT400 Chevy Pickup – So Far“
Oh, if I’m a professional anything, I’m a professional sayer of “eh, that’s not a big deal,” even when it is. The rust free truck is for sure a deal at that price. I think I incorrectly made the inference that you were somehow unhappy about these things. I get that you have to write about something, too, so maybe its better for engagement to sort of present it that way.
It was under $5K, it’s *rust-free*, straight, and presentable looking. It even runs decently. Nothing else really matters and is just wrenching. It could be showroom-looking with not a single issue when you look at it, and it would STILL puke something up within the first few months. The way of old vehicles.
Where I am, one of these beat to shit with 200K on it is nearly double that. Easily. And up north every fastener underneath will be lumps of rust, even if you luck out and the frame is solid. Making doing anything absolute and utter misery. And it will cost just as much – and you can bet the A/C won’t work because the salt will have rotted out the condenser and all the lines. This thing was a steal even with the issues.