Fellow ROVERS!!

May be a dumb question since these old girls aint race trucks.
i live at 4700 feet above sea level in the california san bernardino mountains. every day i make the trip up and down from 1000 feet up to 4700 feet. its a 4 lane highway with 12 mile stretch between the 2 heights so the grade can get pretty drastic at times but this road has an average speed of 55-65mph aside from the switchback/hairpins at times.

Im just asking if its normal for a Disco 1 not to maintain +50mph in 4th gear up hill? If i keep my speed below 49mph i stay in 3rd and maintain -49 mph well. but as soon as i reach 51mph the trans shifts to 4th as it should and i lose speed again soon shifting back to 3rd. I just dont like making the trans shift back and forth from 4th to 3rd just to maintain 51-55mph. My shift points at RPM are correct and this old girl has the correct tunes ups done when needed. I will sometimes select 3rd in the gear box for the whole trip up to avoid the back and forth shifting but dont wanna make her work too hard since shes my baby.

Is it normal to not maintain 50+mph in 4th gear uphill?

Am i having engine/transmission problems (lag or loss of BHP)?

Do i need to do more extensive tuneups since our girls lose Horsepower over time.

I only ask this becasue i see so many beat *** cars/trucks passing me by with ease while i hang on at 49mph to hold 1 speed

I know i can beat em off road, but as they say Rovers are turtles not rabbits.

thanks

96 Disco SD
166K
new trans, 30k tune every year, ngk plugs/wires, lucas adds, 235/75/16 Hancook ATM, stock suspension, all fluids and filters on time. Bluetooth live data OBD2 scanner. Well taken care of. No codes in a long while

 

Its hard to say if what you experience is normal or not.

I cant really speak for the D1 as i haven't driven mine enough yet.
My dads D2 with the bosch 4.0 doesn't behave in the way you describe though and I would think they wouldn't be all that different from a D1.

Normally i find that on the highway it does really well on inclines.
I attribute this to the fact that in 4th gear doing say 2500/2600rpm its right in its power band and doesn't slow down much. Depends of coarse on how steep its climbing.

What size tires are you running?

 

oh - just saw your tire size in your post

also, like you said you were doing, its probably best to just have it in 3rd gear instead of having the transmission gear hunting.

If it is a really steep hill though, 49mph uphill doesn't sound too bad for a 4wd brick

 

Try a different spark plug, like the Bosch Platinum +4 and a good set of wires. But it is heavier than a lot of the pickups that pass you.

 

Mine does fine on it's own but when pulling my PA trailer, Not much reserve power at all.. But you have to remember 4.0 liters is only 244 cubic inches... Not much of an engine...You'd think they'd get better mileage...I have yet to look at the plugs on mine.. I guess that's about one of those things I should do now that I actually have it able to be on the road...

John

 

yeah, the drive gets pretty steep. this truck handles itself very well on basic highway inclines and this road is pretty darn steep. ill try the bosch 4+ plugs next time around. on another note, ive driven up the mountain with other discos and they dont seem to be doing any better. 4.0 isnt much liter for a large suv uphill at 50+mph. if stay in 3rd i can easliy reach speeds of 55-62 at about 3200RPM. I am hopeful but its also gotta power 4 tires at all times so its making sence to me.

 

if im really stepping on it, it does a little better but im use to babying the drivetrain. perhaps im getting a bit of wheel drag. i figure if i reduce wheel/bearing resistance it may do better. like wheel bearings, service hubs, ect.
any suggestions on reducing wheel to street resistance?

thanks,.
im hoping to hear a disco 1 owner that gets a simlar problem.

 

Being I live in the flat lands where you have to drive 150 miles to go up 300 feet in elevation, not much experience there. Don't think rolling resistance is much of the equation here. Air filter and other things may add up to a little change. Need more giddyap.

 

Just run her in 3rd while climbing the mountain, wont hurt anything but constantly gear hunting will raise the trans temp.

 

I experience this problem on every hill I encounter but I am pulling 285/75 MTs on stock 3.54 gears