76 Pinz 710k Highway Travel

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76 Pinz 710k Highway Travel

Post by BobV »

Hi everyone, I'm a proud 76 710k Pinzgaurer owner as of February 22. As I'm sure all of you owners are I'm very excited to own this amazingly well engineered vehicle. I'm totally taken by it's capability & functionality. I was lucky to get mine stock spending it's time in the Swiss Army (mostly in a depot) till 2020. Going through the records & driving this amazing vehicle is such a great experience. From the time I became interested in getting one to now I have tried to learn as much as possible about the Pinzgaurer. I found & contacted Vince of Real 4x4 who recommended I get ahold of Andre at Fat Fabrications who recommended I contact Rick for A SSI system. I'm working with Vice to get a solid 24 volt winch. Was so fortunate to get on Andre's east coast tour. That experience was so valuable! I learned so much more about my vehicle & I contacted Rick, purchased & installed his well engineered SSI system. So much more yet for me to do.

This brings me to my questions. After getting to know & driving my 710k around 500 miles I decided to take it on a longer journey. I planned, took tools, fluids, manuals & a small collection of spare parts. I drove from Glen Mills PA to St. Clairsville OH. The drive to Ohio was about 370 miles one way. Giving the vehicle a good check over I was on my way. I've read & have received a bit of advice about highway driving with the Pinz. Most people state it's alright to drive at the higher speeds (55-65 mph) I read where the top speed is 168 mph. I had planned to take back roads with lower speeds but opted to take the PA turnpike to get there sooner. I obviously didn't run at the 70 mph speed limit but did drive at an avg of 60-65 mph. The engine ran great but the drive train was loud & vibrated a speed. I did stop at several rest stops to rest the vehicle & fuel up. Upon arrival in Ohio I noticed some slight oil weeping on the inside front drivers side portal plate drain hole. I checked fluids & all was ok except had to add nearly 2 quarts of engine oil. The next 2 days I spent doing mild to moderate offloading. The vehicle did great! Time to go home to Glen Mills PA. Aside from a miss & backfire I attributed to a loose carborator solenoid wire all went well with journey back. During the trip though I did notice more oil leaking from the front DS portal. After getting back from over 1000 miles I got under the vehicle & noticed several new oil weep trails. Aside from the front DS portal the oil pan & rear differentials showed fresh oil weeping. I checked the fluids all was ok. Tightened the oil pan. Surprisingly didn't have to add engine oil or any for that matter. I wiped the oil weep locations then drove 30 miles on back roads at lower speeds up to 50 mph. Got back & no oil weeping. The vehicle ran great. So after all this message my question is what is in your experience & knowledge the maximum sustained highway speed for the 710? I had drive train vibration but test drove with Andre & he felt is was normal & showed me that driving in four wheel drive greatly reduces it. Another note. I topped up fluids before my trip. I know this topic came up before with mixed comments. Could I have over filled my front axle fluid causing the portal weep hole leak? I am planning a longer trip to a north east Maine. Want to take lessons learned and not risk avoidable damage to my vehicle

This forum has been so very helpful. Thanks to everyone for your post, contacts & feedback! Any help with my understanding & maintaining this amazing vehicle is appreciated.

Thank You,
Bob V
BobV 76 Swiss 710k
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Re: 76 Pinz 710k Highway Travel

Post by rmel »

Congrats on a nice Truck and blessed by Andre :D

Now....your bringing up several possible issues here w.r.t. leaking fluids.

Leaks cab be sneaky and at times hard to nail down -- and -- they drive me crazy.

Starting with the Portal, if you are seeing oil leaking out of the plug and nowhere
else, this just maybe a bad copper washer e.g. one used too many times and
got work hardened. Also a common mistake is to forget to pull the old one out
and stack a new right on top of the old. If it's just a tad loose be careful not to
over tighten. And best practice is to use new washers (or annealed old ones). If
your lucky this is Leak #1.

If you lost 2 quarts of Engine oil that's a lot for a 1,000 mile trip. Although these
Air cooled engines do burn oil -- on purpose -- to help cool the Exhaust valves.
There are several sources for leaks on the cylinders, given there are 28 "seals"
associated with the 4 cylinders. Not including the oil cooler side of the motor.
Look at the sides of the engine block for any wetness, oil running down the side
of the central tube or along the bottom running back toward the rear diff. If you
see any of that then there's a bit more work to figure out where it's leaking. If
completely dry yet you consistently loose oil then it's going out the tail pipe; rings
or valve guides as a possibility. Not a bad idea to do a compression check just to
baseline where you are.

Incidentally, depending upon the Oil filter you are using, you can get "tricked" on
oil level. Some filters have a anti-drainback valve. With the filter is mounted
horizontally it's possible to read a low level with the filter holding a max amount
soon after running but then may leak down after a few days so you may get readings
that are -- well -- confusing.
Puller: 71' 710K 2.7L EFI aka Mozo
Follower: Sankey MK 3, 3/4 Tonne
Rescue Pinz: 73' 712MK

Driver: Ron // KO0Q
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Re: 76 Pinz 710k Highway Travel

Post by ChickenPinz »

Welcome to the family, Bob!

A few thoughts on your experiences:

On the DS oil leak, try to get everything nice and dry so you can carefully ascertain where the oil is coming from. In my case, I actually had a mis-machined fill port plug on the DS portal that was leaking. If it's truly from the weep hole, I'd pull that left front wheel & drum and look inside. And check the level of your center diff case to see if it's leaking from there outward.

On engine oil level, even some filters with anti-drainback valves will leak. I'd recommend for a good oil level reading, run the engine and then check the level shortly after engine shutdown for a consistent and accurate reading. Folks recommend the Mann 940/5 filter which does include an anti-drainback valve.
https://catalog.mann-filter.com/NA/eng/ ... /W%20940~5

Speed and vibration. Assuming you're running relatively stock tires, 60MPH is a comfortable cruising speed on the highway. I find about 63MPH it starts to *feel* like it's pushing things, but redline is higher so you can reach those higher speeds (near 70MPH). Book max speed is 104kph (65MPH) with stock tires and gearing on a 710. Also, be sure to check your speedometer calibration. Easiest way is with a GPS.

There are many kinds of vibration, but there's a very Pinz-special one due to the funky (read: special) driveshaft to the front diff. In short, it's somewhat twistable and flexible, and they can develop a low-frequency vibration/rumble that tends to increase with increasing mileage. Fixing it is *very* involved, so most (?) folks just live with it. What Andre's telling you about running with the front axle engaged will stop the issue, but then you are driving a part-time 4WD vehicle on a hard-surfaced road so it's going to put increased load on the system. How much load depends on how well matched your front and rear tires are, and how many turns you take, and how big of a deal that load is is hard to quantify. But without a center diff, there's going to be extra stress on the system -- but that wow-wow-wow vibration will be gone.
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Re: 76 Pinz 710k Highway Travel

Post by BobV »

Thanks guys for your valued experience & feedback. I'm getting to know this vehicle but still so much to learn. Andre's visit & communication with other owners is a huge help. Before even getting my Pinz I ordered & reviewed all of the manuals. Upon receiving it I was pleasantly surprised at the good condition for a 46 year old vehicle. Having the original Swiss army maintenance records helped. Before leaving on the Ohio trip I checked over main systems (as much as I knew & could do). Also after talking with Andre & converting over to Rick's SSI system. I felt ready to go.

My main concern was I've been driving for nearly 7 months with no leak issues other than the need to lightly tighten the front passenger side ball joint scraper plate seal. With this 1000 mile trip it seemed that vibration & heat gave me something new with oil weeping. After the trip my engine oil drain pan was loose enough to where I believe the majority of the engine oil loose may have been there. I tightened it up & seems much better. I changed the oil & filter with the European original issue from SAV before the trip.

After tightening & wiping down the weep locations all seems to be ok after 30-50 miles at lower (not exceeding 50 mph) driving.

You've given me alot of good things to look for/at. I took note & will do. Also gave me good experience & insight on vehicle speed & vibration. Although my speedometer works I am using GPS for verification. I have a couple of months before wanting to take my Pinz to the Maine backwoods. A challenge for any vehicle. In my short time of ownership I grow more amazed at the engineering & capability of this vehicle. Looking forward to learning & traveling more with it.

Thanks again gor your valued feedback & to Vince for this forum.

Best & Safe Travels,

Bob V
BobV 76 Swiss 710k
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