L400 Overdrive - A few questions

[jamieboycowtown]

Hey

Heading to mountainous BC next week and had a few (potentially dumb) questions about proper use of overdrive on/off switch in my L400. Did same trek last year and experienced some rpm lag (and subsequent engine temperature heat spike) on a couple big climbs (e.g. East-bound Coq, Princeton-Hope) with OD on.

Plan this year is to tackle these climbs with OD off to keep rpms up and engine heat steady. A couple of questions:

Is it recommended to flip OD off and on (based on terrain) while moving at highway speeds? If so, are there speed ranges i should target when it comes to flipping between OD on and off?

Any thoughts? Thanks in advance.

[Mr. Flibble]

You can turn OD on or off at any speed. In general: off for up - especially when you need to pass. On at all other times.

[RickJ]

I just arrived home from a trip to Calgary with our L400. We packed light which means with two adults and two children we were full to the brim. This was really a voyage of discovery for us driving this van on long hard trips. We have been on shorter excursions as in around Vancouver and up island and even a trip to Oregon but nothing as hard as the Rocky mountains.

On the way out the ambient outside temperature was around 30 and above. I pushed the van to see what kind of temperatures we would see. I found that on the long hills and the OD left on it would not take much to see exhaust temps spike up to 1100 F at 100 km/h at which I would take my foot off the pedal to let it drop. I also found that my coolant dummy gauge would start to rise to the 3/4 mark at this speed/load but come back to the 1/2 mark once I eased off. My engine oil temp as well as trans fluid temp would also rise significantly.

On the way home, the ambient temps were slightly less. On the long hard hills I would knock the OD off and get into the slow lane behind the trucks. I could maintain 80km/h no problem with RPM's around or just below 3000 and egt's never moved above 900F. oil and trans temps never spiked and the coolant gauge never budged off 1/2. Not even once. I believe this is the way to drive now on the long hauls

As for the coolant gauge, I am not sure how much higher it would have gotten above the 3/4 mark. Perhaps it would have been fine but being that I have never seen it move and the hills can be long I was nervous about pushing and boiling over. Perhaps someone else can add some experience on this.

On another note...I found that during the first few days in Calgary the van was very sluggish, spewing black smoke out of the tailpipe starting off from stops. At first I chalked this up to overdosing it with Howes additive as I usually use the Powerservice, but now I am wondering if it had something to do with the altitude compensation device on the fuel pump.

All in all this was a very good experience and really not knowing how it would do I am fairly happy with it. Our plan is to purchase a travel trailer but I may reconsider this trip towing unless we just opt for a tent trailer. Again, perhaps someone else has more experience with this as well.

Hope this helps.

Rick

[Big-Bird]

I have an L400 and do the slow lane thing on the steep inclines. Its just better for the motor when I take it easy up long steep climbs. However I did install a new radiator last fall and did notice better cooling efficiency. It was new, not different from the OE rad. I also make a point of switching on POWER mode with the Transmission Switch on the dash, this changes the shift points and provides a little better climbing speed.

I only had black smoke when my EGR started to fail and I have been all over western canada with my Delica with no performance change related to altitude....it was all mechanical issues.

I live in Calgary and don't have sluggish performance....and CVI did the tuneup over 2yrs ago.

[thelazygreenfox]

Guys
If you are seeing any spikes in transmission temp a larger trans cooler may be a good idea. In these present 30-40 deg. temps it can't be a bad idea. I'm considering a larger cooler for my V6 although the trans temp didn't budge in last weeks fishn trip to central BC.

Incidentally the Invecs 2 trans in my 99 chamonix is a very slick transmission, downshifting earlier on climbs, has a hold position and downshifts on downhills on it's own. Much less braking needed. The V6 has lots of power for climbing with great gas mileage too.