Unimog Camper Adventure Part 1: To be Continued?

[Tennmogger]

Really sorry to hear of your tranny problem. Did the transmission still refuse to shift after a complete cool down? If so, you might have to replace it (replacements are available). These transmissions tend to get hard to shift if they overheat, which yours obviously did.

But, your description was somewhat optimistic! If it will still shift at all, you might try changing the lube to a good synthetic lube made for synchro trans, like Amsoil MTF. That's what I use.

Speed=heat is the enemy. If the transmission still works then slowing down will make a huge difference. Not only is hard shifting a typical heat-related problem, there are bushings in these transmissions that overheat and weld themselves together. Using the best lube available will help avoid those hotspots.

Do you see that plate on the right side of the trans housing, just in front of the dipstick? That's the opening for a side-mounted PTO as used on the really early transmissions. If you replace the transmission you might want to upgrade to a newer trans/case type.

Glad you intend to haul, not flat tow. Flat towing would be the final nail in the coffin for the tranny!

Bob

A ways in to New Mexico, en route to Los Alamos, the truck suddenly started slowing in 6th gear on about a 6% downhill grade. The feeling was like shifting in to fifth with the throttle closed. Examination showed the transmission to be hot enough to smoke the gear oil. The transmission did not reliably shift into any gear. There was no grinding or sheared metal in the transmission oil, but the one week old change of GL4 90wt had a burned smell to it. It also had a consistency incongruous to that of gear oil. The poor mog is still on the side of the highway. To be continued! (fingers crossed)
-CJ

 

[jackflash]

desertrover, sorry to hear about your troubles. Hope you get it back on the road soon.

Just had to comment on the second picture in your first post, kinda crazy how the tires appear to be moving but the drive shaft doesn't. Funny stuff.

 

[desertrover]

Tennmogger, Are you referring to the small hexagonal cover with six bolts near the trans dipstick? It would be surprising if I have an older style transmission in my later model 404.. It is a 1976. Could I have a transmission not original to the truck? If I do need to replace, I'm fairly local to EI, so I could avoid shipping.

Jackflash: Unimogs use a torque tube, the driveshaft is fully encapsulated in a steel tube.

 

[desertrover]

Update: drained trans, filled with Amsoil MTF. Gears still stick, neutral dosen't work, and I only have 1st and 3rd gears. Looks like I'm in the market for a transmission, and have a need to remove my cab and engine. Ouch!

 

[Cody1771]

that really sucks dude! ive had to leave a vehicle on the side of the road for awhile, its really stressfull, especially if its in a remote area. im not up to date on Mog's but dont those things have some sort of tranny cooler? 80C seems really high to have your oil running at. might be a good idea to build a wood A-frame with some chain blocks like that guy had for his camper, would make the job easier in your yard. im not a big fan of paying mechanics whenever i can avoid it, id rather put the extra $$ to higher grade components.

 

[762X39]

Wow, 55mph for any length of time is probably what killed the transmission.I have found that my Mog prefers speeds in the 45mph range on level ground or even a slight decline. I have also found it better to drive before the sun reaches it's zenith (I try to drive my Mog between 4:00 am and 11:00 when I am on a trip. That way I can enjoy wherever I stop for the better part of the day and have a nice siesta while I'm at it.Unfortunately (or not), it is better to adapt to your Mogs weak points then trying to overcome them.
As a side point, use synthetic fluids in you transmission, diff and portals to give you every advantage possible.

 

[desertrover]

My tires are about 10% oversize, so 55mph is a pretty sane RPM. Won't hold it with a headwind on level ground though. Am I correct in my understanding that heat is the enemy here, and high rpm causes heat? My next transmission will definitely have a temp. sender attached to an in cab gauge.

 

[762X39]

My tires are about 10% oversize, so 55mph is a pretty sane RPM. Won't hold it with a headwind on level ground though. Am I correct in my understanding that heat is the enemy here, and high rpm causes heat? My next transmission will definitely have a temp. sender attached to an in cab gauge.

Keeping tabs on the transmission fluid temp is a very good idea.Heat is the enemy in a 404 which is why I try to drive when it is cooler outside.I find that my Mog just plain runs better when it is cool so I plan accordingly.

 

[desertrover]

Update- Just got back down to Twentynine Palms with a new transmission for the Mog. Much thanks to Scott and EI for making these things available! It wasn't quite smooth sailing though.. I was driving my Range Rover, and while non-leaking rovers may be the ones out of fluid, mine has developed a massive transfer case leak. No fun to top those things up hot on the side of the road. Also, the accordion pipe on the intake gave out. It is constructed of what looks like a long loose coil spring with an airtight cloth material laminated inside and outside. The inside layer delaminated, causing the intake vacuum to suck it shut and stall the engine. The quick fix that got me the remaining 300 miles down here was an old spray paint can with the ends removed fit into the pipe. Photos soon!

 

[dzzz]

At some point soon I expect a Toyota Camry will be looking pretty darn good.

 

[desertrover]

heh, a Camry is a good little car, but not so good for hauling Mog transmissions and 4x4ing through the desert. I suppose if it were, it would be called a TLC!

 

[desertrover]

Well, a final update on this one.. New transmission in, and the Mog lives on. Many thanks to Scott at EI, the staff at the MCCS Hobby Shop, and everyone else who lent a hand putting it back together.