T400 gear changes?

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paulmorton

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Paul
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84
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K30
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Hi guys! My truck finally is road legal here in the UK ! Just a couple of questions transmission wise obviously as I've never had one of these before!

Out on the road the gear changes seem good nice and smooth but on grass it seems to loose grip and try to spin the wheels?

Also on the road it seems to get into 3rd before 30mph and is screaming it's **** off by the time I make it upto 55/60mph?

So far it's had a new modulator and a top up of fluid I'm guessing a proper service would help but after that is there anything else I could check or is this normal?
 

CSFJ

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Sounds about like mine. As far as the tires spinning on grass, keep in mind that you have a couple hundred + pounds of weight in the nose above what a normal gas big block weighs. The screaming rpm at 55-60 mph is thanks to the 4.56 axle gears. When I first put mine on the road, it felt odd to me too. Pretty moch used to it now.
 

paulmorton

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So it's normal then? Just seems weird to use all 3 gears below 30 and nothing after? Is there nothing that can be done? Just thinking of diesel prices over here really?
 

CSFJ

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It's the nature of the beast. I know in my truck if I really get into it, the shift from 2-3 won't happen until about 50ish mph. When I fist put mine on the road, I manually shifted it just to make sure it was using all 3 gears. that 2-3 shift in light throttle happens so quick, that I didn't notice it the first time I drove it. As far as getting in to 3rd so quickly, you want it to be in final drive sooner to knock down the rpms as much as possible for the sake of fuel mileage. the only way it would improve, would be to re-gear the axles. The downside to that, is the 6.2 isn't a powerhouse and needs all the help from the gears it can get. Fwiw, future plans for mine include a manual 4speed overdrive trans, that was available in the civilian model trucks on this side of the pond. I figure the .7ish o/d ratio should get me close to a 65 mph cruising speed, and lower rpms around town.
 

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