3930 Transmission fill level

[3930dave]

Hi all,

Newbie (redundant if asking about the dipstick - eh ?), just picked up
a '92 3930, manual 8spd.

Been working thru some basic maintenance, changed the hydraulic filter
today (another post coming on the filter issue) and wanted to ask some
questions about the transmission fill level.

Apologies... I only have my webcam, so had to take a picture of a crude
sketch, the dipstick itself wouldn't look like much on this 'cam....
(The dipstick is straight.... I just can't sketch today....)

I do have the factory operators manual, it says "....check that the oil
reaches the upper mark on the dipstick..."

What I am trying to get across in the sketch is that I can only see ONE
mark on the dipstick. When I got the tractor, the oil level in the
transmission covered the FULL letters on the stick, coming right up
to where the flat portion of the dipstick ends.

I'd like to think the drivetrain can tolerate some overfilling, but with
what (very) little I know about hydraulics it seems that things can get
weird with too much oil.

So... just wanted to ask the brain-trust here:

1) Do I use the Raised Mark to indicate full, or do it top it up to the
end of the flat portion ?

2) The top portion of the dipstick has several grooves just under the top cap.
Were O rings originally fitted here ? The dipstick pulls out with very little
resistance, I'm wondering if the O rings fell apart or where removed.

Any suggestions on O rings ? I suspect there are some junk brands/materials out there - I don't want to slightly increase the seal here by contaminating the oil with self destructing O rings.

Thnx, Rgds, Dave.

 

[HickoryNut]

I'm pretty sure my '92 4630 has the same 8x2 tranny. Dipstick is confusing as there is no "upper mark". Mine came from the factory filled to just above the full word where it tapers from flat to round. After changing the oil a couple years ago I found after refilling spec amount it indeed came to that same level. I'd estimate that lower mark to indicate at least 1/2 gallon low. As far as O-rings, mine has the grooves but I'm pretty sure there was never O-rings in those grooves and it does fit kinda loose. Here's some sorry pics to help illustrate.

 

[jinman]

Does the tractor have remote hydraulics? That oil could have come from an external single-acting cylinder. If the reservoir is filled with the 3PH lifted and/or an external hydraulic cylinder extended, then on lowering the 3PH, the fluid will go over the full mark. You should always check fluid with the 3PH in the lowered position and other attachments like an FEL at the lowered/retracted position.

Another way that reservoirs get overfilled is when someone reads that the reservoir holds a certain amount of fluid, like 10 gallons. They buy 10 gallons and then drain the reservoir. Because oil is trapped, they may only drain 8 gallons, but they worry that the spec said 10 gallons, so they put the whole 10 gallons into the reservoir. The tractor may also not be on a level surface and the dipstick can give a false reading.

At any case, I'd put the tractor on a level surface and fill to the line. After that, you should be good to go.

 

[3930dave]

Hi HickoryNut

Many thnx for the fast/detailed response. That is exactly the "own since new"
answer I was looking for - from your pics - same dipstick. Glad to hear I wasn't the only one wondering.... with tech info, it is often the simplest issue that can cause the most grief.

I picked this tractor up from an auction about 2 weeks ago. Have changed the motor oil, and anti-freeze so far, will likely change the hydraulic fluid in a few months (don't have a realistic way to heat up the tractor for a proper hydraulic drain till spring).

The hydraulic filter had to go, aside from being the wrong filter, it clearly had been on the tractor too long. Initially, I was thinking the transmission and hydraulic system drew from the same reservoir, after some more reading... seems not so. (The rear axle and transmission have separate drains/fills, with the rear axle rated at something like 45litres/12 US gallons).

I will double check the transmission level, but now wanted to ask about the rear axle level. I haven't pulled the rear axle dipstick yet.... manual says "...and refill the rear axle until the oil reaches the UPPER mark on the dipstick". Do we have the same "virtual" upper mark again ?

Any comments on Hydraulic oil preferences ? I have a couple of emergency quarts of the NH Multi G 134, but will be shopping around for the big change. Best I've found so far is the Tractor fluid at Walmart (Tech 2000 line here in Canada), it is M2C134D rated.

On a separate topic - do you adjust your valves yourself ? If so I will post a separate question.

Hi Jim

Also many thnx for your excellent general points... I used friends tractors when a young pup (a while ago now....) but other than fueling and oil checks didn't have to any maintenance. So... am really enjoying this site... a big help for things I've forgotten/never knew.

No FEL yet, and as far as I can tell no Remotes (meaning to me something like a dedicated loader control). I will check the rear axle level with the tractor level, and the 3pt lowered.

Agreed, you can get into trouble just blindly following fill ratings - and overfilling can have some funny effects - years ago I saw a GM 4 cylinder engine that looked like it had serious lifter problems.
Turns out, the crankcase had been overfilled to the point of serious aeration and the hydraulic lifters were clacking as a result - bleed off the excess oil - much happier lifters/owner. That story is one of the reasons I pay attention to the measured level....

So far I've been pretty impressed with the factory capacity vs. drain ratings (motor oil, antifreeze), but would never assume them to be exact - just happy to know how much to buy !

I have a lot to learn about hydraulics... I'm sure I will be posting more questions on that subject and many others.

Thnx again both for your time.... Rgds, Dave.

 

[HickoryNut]

Rear axle/hydraulics has a much more "intuitive" dipstick, holds a little over 12 gallons, transmission holds a little over 3 gallons. Very wise to change antifreeze, seems to get acidic very quickly in these tractors, make sure to add the DCA additive per spec. I've checked my valve clearances twice and found no need for adjustment. You may be about due for resealing the injectors also, check for leakage and/or hard starts. Only serious trouble my tractor's had was starter failures and one of them bolts is a bear to get off. Make sure to check your clutch pedal adjustment. I use all NH filters and hydraulic fluid, my hydraulic filter has a habit of vibrating loose. Be careful what you pry against to tighten your fan belt, I've busted two thermostat housings in my ignorance. There ya go, pretty much sums up my 15 years and 2000 hours seat time of experience with this model tractor.

 

[3930dave]

Thnx again HickoryNut !

Someone's tag line here has that quote from Will Rogers about experience and the 'lectric fence. Hard earned knowledge is very valuable.

I used an Afreeze made by Vulsay (Flo-Perm), it has the additive pre-loaded and is rated for HD diesel applications - it is what the local NH dealer uses all the time. I knew that diesels needed different AF, have been learning a bit about why. One site that details some of the reasons is below... I found the cavitation/pitted liners issues interesting in a dangerous way.

Cavitation

Vulsay Industries Ltd.: Innovations

Not sure... Vulsay may be only available in Canada (?).

I'll toss the details of my Valve question in a separate thread tomorrow.... jist is that the circa 1994 Operators manual seems to have a typeset error in the valve adjustment section, I think I can figure it out, but don't have the mech relationship of a 3 cylinder clear enuff in my head yet to be sure... question for another day....

Knock wood/my head, no hard starts/leakage so far... I have to re-read the injector section again, I seem to recall it as an injector replacement activity... This is my first diesel as an owner.... is the deal that the constant vibration ends up unseating/sealing the injectors - as opposed to the injector
actually wearing out ? Tractor has 1480 hours now.

Thnx for the clutch note... I intend to work thru all the basic adjustments and lubes, I'll put that at the top of my list.

I was surprised to see the starter being serviced (cleaned) - sounds like the clutch dust is a problem - did this contribute to your starter problems ?

I'll watch the Hyd. filter - I thought the old one was just baked on, but possibly someone really reefed on it to deal with the vibration issue...

I'm a big fan of OE filters - I only move to an alternative if I'm really convinced of a quality improvement. There seems to be plenty of no-name (house brand) Ag hydraulic fluid around - I work in a different area of technology, but the same rules apply - if it doesn't list the OE spec rating, don't consider it - I will definitely price the NH fluid in volume.

Thnx for sharing... this tractor seems to have been decently maintained... I'm hoping with a little luck I'll have it for a long time....

Rgds, Dave.