Early msg-5 durability behind a c223t

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teener
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Early msg-5 durability behind a c223t

Post by teener »

I've heard that the early msg-5 is weak compared to the later version or the mua. Are there success stories about these weak trannies surviving when driven reasonably?

I plan to put a c223t in my 2wd longbed. At most I'll ask it to haul two dirt bikes and a passenger over a 5000' pass, but no more stress than that. I have a fast car to romp on, my luv is a commuter.

What is the mode and presumed cause of failure on these transmissions? Wear, gear breakage.....? Hauling heavy loads, clutch drop burnouts....?

I have a msg-5 from a 2.3l in waiting but would prefer to find one from a diesel or turbodiesel for the gear ratios. Also, it has the wrong speedometer ring gear and would require a converter.

Basically, I want to nurse along my early diesel msg-5 until I find a more desirable tranny. If it is absolutely futile then I will reconsider.

So, what are your success and horror stories and what are/were the conditions?
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puttputtinpup
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Re: Early msg-5 durability behind a c223t

Post by puttputtinpup »

I've heard from Jerry Lemond that a couple of the primary reasons they fail are refilled with incorrect oil, lugging engine in 5th gear, weak 5th gear bearing. In some of the transmissions, they used open bearings (no seal on either side of the bearing), some they put a seal in one side of the bearing, and perhaps some had seals on both sides. I'd probably add low oil level, and speedshifting the poor little things and forced downshifting wearing out the synchros.

Others feel free to chime in.

Dumping the clutch and burnouts are rough on any transmission.....which coincidentally (confessed years later) was why the 5speed went out in my son's diesel LUV.

Driven easily and correct oil put back in them, they should last quite a long time.
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Re: Early msg-5 durability behind a c223t

Post by JoeIsuzu »

I'm a little surprised yours has the wrong speedometer ring gear. How many teeth does it have? Counting them is tricky, since it's a worm gear. I've seen mostly 6 -- that is, on EVERYTHING but mine. Mine was from an Impulse, and has 5 teeth. I considered trying to use the one from my original '83 transmission, but it would not fit the tailshaft.

Jack
teener
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Re: Early msg-5 durability behind a c223t

Post by teener »

Thanks for the insight puttputtinpup. Based on your report I'd feel comfortable using my existing tranny. I'll wait for others to chime in as well.

The spare I have is from a ~'92 2.3l pickup. It has the 5/something input gear.
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Re: Early msg-5 durability behind a c223t

Post by Halden »

teener wrote:Thanks for the insight puttputtinpup. Based on your report I'd feel comfortable using my existing tranny. I'll wait for others to chime in as well.

The spare I have is from a ~'92 2.3l pickup. It has the 5/something input gear.



I don't think you'll notice a difference between how they are geared, especially with the Turbo. Makes for a totally different experience. I'm almost 100% certain my 82 has an upgrade trans in it and I have no problems with the gearing. I'd just throw the stronger one in there and be done with it. Especially since it would be pretty advantageous to do it right now. O/D is the exact same ratio.

Andy mentions not lugging the engine in 5th gear, which I believe is crucial, but I've found many people have a different definition of lugging. I've heard [good :wink: ] Jerry say not to throw the truck into 5th at speeds lower than 50-55. Basically not using that trans in 5th below 2200-2300 RPM

Having a turbo means you can obviously push it harder than that specific transmission was designed to take. Considering it was already borderline strong enough behind an NA you'd probably have to be tamer with a turbo and not really take advantage of it where a turbo counts... Hauling a load up a grade or a hill.
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Re: Early msg-5 durability behind a c223t

Post by ZUZUFLY »

JoeIsuzu wrote:I'm a little surprised yours has the wrong speedometer ring gear. I considered trying to use the one from my original '83 transmission, but it would not fit the tailshaft.
I drove my 81 Luv diesel probably 400K to 500K miles. Speedometer had to be fixed a few times so just a guess. I think it was on 378,00 when I parked it for losing power and fuel mileage. I had the original tranny in it all that time. I pulled it several times to replace a bearing every now and then. I had to replace the counter shaft once. Once I put a complete kit in it. I think it had about 70K miles when the first bearing started making noise, was worse in first and 5th. 4th no noise since power flow was straight thru. It was the big bearing on the input shaft. I replaced it from the front. It went to about 125K then the little bearing on the 5th gear got noisy. I got good at removing/installing the tranny once I got the procedure worked out. I did drive it in 5th gear all the time, probably too much. But I was/am a dummy not knowing any better. I went to using Mobil 1 15w50 synthetic oil and that made the bearings last longer and shift better than gear oil. Still has the original clutch in it. Replaced the thro-out bearing once.

I didn't learn about the later gasser tranny upgrade until I read it on this forum. Later I got an 84 Pup diesel. I put the gasser tranny in it. To solve the speedometer accuracy issue I took the nylon gear out of the early tranny and bored out the ID on a lathe and filed the 2 slots to fit on the later tranny output shaft. No change in speedometer reading cause it was the same gear as before. Made it kinda thinwalled but has worked fine. I purchased a yoke from JLEMOND for $140 to adapt the drive shaft. The used tranny came from a local NAPA store out of a local parts delivery truck. I did not overhaul it, just inspected it and swapped the diesel bellhousing to it. At first 1st gear was a bit tall, I kept choking out the engine on grades but I got used to it. The gear ratios are slightly different but workable. The gasser gears are about 50 percent wider than the original but the bearings are petty much the same. I have put probably another 100K miles one the gasser tranny now. No idea how many miles were on it before I got it. Its getting a bit noisy now and will be needing some attention before long.
Last edited by JoeIsuzu on Fri Jan 08, 2021 10:50 am, edited 1 time in total.
Reason: Fixed quoting
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puttputtinpup
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Re: Early msg-5 durability behind a c223t

Post by puttputtinpup »

Glenn, it's good to hear from you on here again. Hope you're doing alright. Thanks for the input on the transmission. I'm currently without a Pup, but always looking for a great deal on a barnfind.
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Re: Early msg-5 durability behind a c223t

Post by teener »

Halden, thank you for the input on the gearing and the 5 gear warning. I think I've been lugging mine, though not under much load. What is the outcome of lugging in 5th? Oh, and I'm sure that extra 30Hp/X torque is intoxicating and it will be difficult to keep my right foot on its best behavior.

ZUZU, I'll look in to putting the gasser speedo gear on a lathe and cutting some keyways. Can't imagine there is much load on that gear (speedo cable and speedo).

I don't have my manual here now. How is it swapping a 2wd tranny with the engine still in place?
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Re: Early msg-5 durability behind a c223t

Post by JoeIsuzu »

teener wrote:How is it swapping a 2wd tranny with the engine still in place?
I would definitely not remove the engine just to replace the transmission. It's handy to have a transmission lift or even a floor jack, especially when putting it back in.

Jack
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Halden
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Re: Early msg-5 durability behind a c223t

Post by Halden »

teener wrote:What is the outcome of lugging in 5th? Oh, and I'm sure that extra 30Hp/X torque is intoxicating and it will be difficult to keep my right foot on its best behavior.


Lugging in 5th causes a lot of hammering on the bearings and gear faces. The pressure from initial combustion really smacks hard on those gears and the bearings aren't quite beefy enough to take it over time. Add a turbo to the equation and in my opinion you're asking for an even earlier failure. I think even the Mazda diesel pickups had the same problems. The engines just chewed the trannies up... Isuzu tried eliminating the problem in 84 and 85 with a spring loaded backlash eliminator on the front of the countershaft, but it apparently didn't help since transmissions were still failing hence the upgrade to the diesels in 1986

Mind you I am of the opinion you should be able to open a transmission up and it should always look basically new inside given that you can properly operate a manual transmission regardless of the mileage. Considering you really have to baby a "pre-upgrade" transmission, I don't think they're made well enough for the diesels especially w/turbo. I've Opened up a 13spd with over 3 million on it. Looked brand new inside. Bearings were even in good shape, but it was a spur gear trans... Scene syncro transmissions with over 700k look brand new as well.
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teener
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Re: Early msg-5 durability behind a c223t

Post by teener »

Thanks Jack

It will be cool to open these up and see the wear firsthand. I know one has been run with gear oil and lugged in 5th. It has a noisy bearing at idle.

I have some time still before needing to make a decision. It would be ideal if I can find a 86 + diesel or td tranny. The early one I have will work on a temporary basis if I go easy on it. The late gasser will work with a Speedo converter or maybe machined ring gear. So many options!

Thank you all for your help.
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Re: Early msg-5 durability behind a c223t

Post by Halden »

teener wrote:It has a noisy bearing at idle.


That's actually pretty normal. I don't know of a 4 cylinder that doesn't make a transmission sound a little suspicious at idle... Even with balance shafts and a heavy flywheel....
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Re: Early msg-5 durability behind a c223t

Post by Paul »

teener wrote: It has a noisy bearing at idle.


Manual transmission noise at idle is (unfortunately ) fairly normal. It is called 'roll over' noise by the tranny guys. The cause is that the minor changes in engine speed at idle cause the gears to start slapping back and forth. And because there is always some clearance between gears, noise is generated when one gears 'hits' another.

I learned this the hard way by completely disassembling a 4wd tranny to look for a problem and found none. Then, I read about roll over noise. A search for this will get a lot of hits.

If your tranny is quiet when driving the truck it is probably OK.

Paul
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Re: Early msg-5 durability behind a c223t

Post by puttputtinpup »

This transmission was pulled from my '85 diesel because it chattered alot idlling like it had marbles rolling around inside. I did the transmission upgrade on this one. 2 visibly bad bearings is shown in the pictures. Jerry Lemond told me that if I were to replace that bearing, the transmission may still whine a bit due to irregular wear on the gears while the countershaft was misaligned with the main shaft.
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Screenshot_20210109-175252.png
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Re: Early msg-5 durability behind a c223t

Post by puttputtinpup »

Jack, I took theae old photos off my upgrade post, long pressed annd downloaded the images. The file extension was .php and when I went to add them again here on this thread, the forum software said invalid file type, so I acreenshot them and posted that way. Kinda weird but I found a workaround
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