84 Crewcab...AKA..Patches

I decided since it was all apart that I would play with my speedo. My crew is a 84, but the donor was a 89. I have a 96 NV4500 and a cable driven speedo.

Ever since I got the truck the speedo has spun too fast. It has been about 8-10 KM/H off. I removed the speedo gear housing from the tranny, and as Mark Nixon has mentioned, it's your standard mopar speedo housing and gear used from mid 60's on up into the 90's.

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So I find a 27 tooth speedo gear inside. I figure since I'm running 3.54's I should have a 35 tooth unit....nope wrong. With the 35 tooth gear I was now running 20 KM/h too slow. So out it came again and I swapped in a 32 tooth unit. I'm now darn close...think my speedo is about 1-2 KM/H slow....might have to get a 31 tooth speedo gear and try that. I have a good selection of speedo gears from parting out mopars over the years...but I don't have a 31 tooth gear. But these are readily available.

I'm running stock 235/85/16 tires and rims...so this is pretty close to a stock set-up.
 
And a couple pics of everything done and back in place....

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The vibration is significantly lessened now...but something is still out of alignment, or balance. I'm going to replace my carrier bearing again and see if maybe I got a bad unit right out of the box? I bought a unit off E-bay so I can't return it for any warranty.
 
I would almost bet on it. Looking at the wear, I would say the rear of the transmission is too high.

As far as speedometer error due to the drive gear, it's always a percentage, not a single number. If you're 5MPH over at 60MPH, you'll be 10MPH over at 120MPH. I don't know at what speed you took your measurements, but if it was at 100KPH, I'd be pretty happy with that. You'll never get it to be perfect. Another thing to consider is the speedometer head; they're not perfect either. This is especially true of non-police speedometers, in which "close enough" is exactly that. A cop speedometer is usually dead-on. If my calculations are correct, with a 1,000RPM input on the speedometer a Canadian unit should read just a twitch under 97KPH (60MPH). My old 9.6V Makita cordless drill runs at 1,000RPM on the lower speed. It's great for this test, and I've tested a lot of speedometers with it. Most are close; cop speedometers always seem to be exactly right.
 
It seems 1,000RPM on the speedometer input is always 60MPH, at least with domestic speedometers. I think it's an SAE standard, but I'm not sure. Electronic speedometers are actually less accurate, perhaps by design. There was some controversy years ago about BMW speedometers being "optimistic", meaning they said you were going faster than you actually were.
 
Cow, are you interested in a dual disk clutch for your setup? I have a complete spare southbend freshly rebuilt clutch (yes, those are rebuildable, and this one was rebuilt by southbend themselves) and oversized input shaft. The whole setup is a bolt in-no harder than putting a stock clutch in. You just won't overpower it. Ever.
 
v8440 said:
Cow, are you interested in a dual disk clutch for your setup? I have a complete spare southbend freshly rebuilt clutch (yes, those are rebuildable, and this one was rebuilt by southbend themselves) and oversized input shaft. The whole setup is a bolt in-no harder than putting a stock clutch in. You just won't overpower it. Ever.
Click to expand...

Might be....PM me with details...;)
 
Doc I don't think the tranny is sitting to high...in fact it's about 1/2" too low by my calculations on the actual drive angle. Right now the actual drive angle at the tailshaft is 0.5%...it should be at 1% to be darn near perfect...but can range up to 3% and still be OK.
 
I was looking at the pictures I took of the original tailshaft bushing...and the greatest wear...where the bushing is coloring green-ish....is to the horizontal plane...not the vertical. So to me this might indicate a driveshaft imbalance that is causing the yoke to wobble side to side?
 
That greenish area is well baked...not much left there. I think it is actually cooked bushing material, because those area correspond with the hottest areas on the back side of the bushing.
 
OK I finally made my decision...I`m going to convert the crewcab to a 4x4. SO the hunt has been on for a donor. I put a bunch of want ads on craigslist, and other on-line diesel forums and received a few responses. For some reason I got quite a few with cummins trucks with 3.07 diffs. I wanted 3.54`s, but could live with 4.10`s. I eventually go a response from a fellow who had a complete truck sitting. He said the truck needed a couple grand worth of repairs so was going to let it go cheap.

I thought this might be a good one. So a couple weeks ago I went out to check it out. turned out to be an original owner truck, 1993 Club Cab, Cummins, Auto 4x4, LE model...full load. Has a few issues, but he was still using it for dump runs now and then. I couldn`t pass it up!

I drove it home earlier this week....Here are a few pics.

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The rear fuel tank strap had rusted out, and tank was hanging down...ratchet strapped helped here.

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Brakes are soft...probably the RWAL valve on the back axle. But the thing steered like a drunkin elephant on the drive home. I later discovered why...The couple on the steering box in toast. I`m amazed it was still steering it is so bad.Rebuild kit on order...;)

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The pass side door is stuck shut, and the door handle is seized. So I will have to wrestle the door panel off from the inside...should be fun. But it has a nice grey interior...going to swap everything over to the crewcab!

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Motor only has 258K Kms on it...about 160K miles. Runs nice and clean, no hazing or smoke.

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Going to swap motor over to the crewcab too when I do the 4x4 conversion. Keep my Non-IC motor as my spare.

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I spent a few hours yesterday, and today, pressure washing the truck, and then scrubbing it down. Looks a lot better now. Wife wants me to drive this truck instead of the old miss matched crewcab...:D I`m very excited about swapping everything over to the crewcab. I`m going to fix a few things on the 93 and then I might insure it and drive it a little. Will probably rebuild the front king pins and hubs as well as service the diffs and everything else and get it all up to par before the donating begins.
 
If you part that nice of a 1st gen diesel truck out for a conversion truck, I'm personally going to have to come up and kick your ass! :naughty:
That's like parting out a perfectly nice '68 383 Barracuda for a ratty assed slant 6 1974 Duster!

Mark.
 
Well I'm sorry you feel that way Mark. I really have been torn about if I should use it as a donor or not though. Truck does have some issues though....enough to warrant it being a donor...well that's subject to opinion I guess. I think it highly unlikely that I would be able to find another donor truck with everything this one has that I can use, and for the money too...that is an issue as well.

With the parts from this truck on my old crew...maybe it won't be so ratty assed......;)
 
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