Outer Limits 4x4 Board

new to this site, needing a little info from those who may know.
I recently imported a 91 pajero into Canada, the problem is at 100km/h the engine is reving at 4000 rpm. It has a 2.5L diesel with an auto trans with overdrive. When it shifts into o/d the rpm only drop 200. I have checked all the obviuos things tyre size, gear ratio (5.28). There is a valve on the trans. I believe it is for the o/d. These vehicles a not very common here yet and it is hard to get any good info on them. Any advice would be great. thanks

It should drop more than 200 rpm when shifting into overdrive. I'd guess that you're only seeing the torque converter lock (does it lock?) and not o/d.

NFI what you do about it... Guess I'd start with coolant temp sensor - if the trans thinks the engine is cold it might not use o/d? What else would cause the trans to lock out o/d?

if it helps anything at all, mine has 5.29 centres as well, but it also has 35" tyres, and it still does 3000 @ 100km/h, so if youve got standardish sized tyres this wouldnt surprise me, though auto and o/d should be more effective than that,

dean.

Sounds like it is not getting 4th gear.

From stop, take off and count the changes.

I checked out the shifting. It is not engaging into O/D. Found three temp. sensors, one for the fan, the other single pronge for the temp. light on the dash (I believe),third has two pronges and I think that might go to the computer to engage theO/D. If anyone can tell me if I am on the right track I would be happy with the input.