GU 2.8 pulling 4600 rpm at 110kmph

[Johnmadeley]

Hey all, I have recently purchased a 1998 2.8 wagon from a car yard, when I got it on the highway it holds 4500-4600 rpm in 5th gear at 110km, any ideas why is would be revving so high? It drives normal but is just pulling bulk rpm! It has 33's and has done 190,000 . I would have thought they did 3000.. ? Help

[the ferret]

Sounds like the rev counter is us mate, shouldn't be pulling those kind of revs, If you jump over to introductions and tell us a bit about ya self, there might be more responses to your question.
Welcome to the forum mate.
Cheers, the ferret.

[nissannewby]

Possibly your tacho is cactus

[Johnmadeley]

its not the gauge I can hear the engine defently revving more then 3000 rpm, I will do that soon cheers mate. It's gone back but I need an idea because I don't want the car yard to try do me over and pay for repairs

[the evil twin]

Uuummmm, that is almost exactly double the RPM you should have for a 2.8 on 33's at 100 ish KPH real speed (allowing for some speedo error).

Are you sure the engine is doing 4600?... It would be howling it's heart out... I would have said the tacho is shagged same as the other guys

If it was an auto then I'd say you have one stuffed tranny but in 5th gear in a manual the only other explanation would mean that the diff ratios must be... like... 8.0:1

[nipagu7]

slipping clutch perhaps ?

[BigRAWesty]

Check your diff ratios. Possibly bolted in 4.6 centers and stuffed the ratio.

[the evil twin]

slipping clutch perhaps ?

Possibility but if it was slipping 2,000 RPM down the freeway I reckon it would have only lasted about 500 metres

Check your diff ratios. Possibly bolted in 4.6 centers and stuffed the ratio.

It's a 2.8 so it already has the highest stock diff ratio (4.62).
Can't be some weird rrse mod to the transfer case high range can it?
Could possibly be the truck was a lemon and stuck in low range but it would do, like, 2 KPH at 5000 RPM in first (joking, but you get my drift)

Hey John,
What is the vehicle idling at on the Tacho and are any of the other gears exhibiting similar symptons

[BigRAWesty]

Possibly an old 3ltr with 2.8 engine and box dropped in. That would throw the ratios out..

[the evil twin]

Possibly an old 3ltr with 2.8 engine and box dropped in. That would throw the ratios out..

Hiya Cobber,

Yeah but unles my maths are out (which happens a LOT) then the ratios would be taller wouldn't they... and the engine revs would be too low?

Your right if it was a mod the other way... a 3 litre or 4.2 into a 2.8 shell and diff

It's definitely a weird issue if it isn't the tacho eh Westy