3.5 Isuzu trooper towing at 4000 rpm

[bonitoman]

When I tow my 4000 lb boat down the highway in 3 instead of overdrive, I notice that the rpm's are 4000 and the engine sounds like it is working hard. Is the rpm range to high to tow for a three hour period on the highway at 4000.

 

[jlinder]

Re: 3.5 Isuzu trooper towing at 4000 rpm

I would not like to run at 4000 RPM for that long. I have a 2001 Isuzu trooper, 3.5L and 4000 pounds to tow, exactly like you.<br /><br />Just curious, are you keeping it in 3 because you had a problem? What speed are you doing with 4000 RPMs in 3rd gear?<br /><br />I run in drive and let the transmission handle the shifting. The most I do is when it gets hilly I select power drive, which changes the shift points (lowers them).<br /><br />I have run for 3 hours or more with no problems. RPMs are fine, and there is a lot of power.<br /><br />The only thing I have done is step up the schedule for transimssion filter and fluid change. I did a change at 50K miles and it shows the fluid was due for a change. I will probably move to every 40K miles for the next ones.<br /><br />Love the Isuzu for towing. Would like a little bigger engine, but not a big deal.<br /><br />Just let the transmission do it's thing and shift for you.

 

[gutshot grouper]

Re: 3.5 Isuzu trooper towing at 4000 rpm

Slow down, you did not say what the road speed is at 4000 rpm, but i would not run it for long at that high speed, unless you plan to replace it shortly.

 

[PeteHarris]

Re: 3.5 Isuzu trooper towing at 4000 rpm

Jack L ... if the fluid looked like it needed to be changed (dark, smell of toast, "stuff" in the filter) then you have already damaged your tranny.

 

[hookless]

Re: 3.5 Isuzu trooper towing at 4000 rpm

I have a 2002 trooper and I tow at 60-65 in 3 and the tach also reads 4000 rpm. I was told by the dealer to not use D since that is overdrive. I did use D one time and the tranny was shifting constantly between 60 -70- mph.

 

[jlinder]

Re: 3.5 Isuzu trooper towing at 4000 rpm

PeteHarris - the fluid did not have the symptoms you talked about, but I was told it was just starting to show some change. Mechanic doubted there was any problem - caught it early enough.<br /><br />hookless - I have not had the problem with it shifting all the time, and I run in D. Have you tried the power drive setting?

 

[hookless]

Re: 3.5 Isuzu trooper towing at 4000 rpm

I have never tried the power drive setting. Would you tow on interstated 95 in florida on power drive in D

 

[jlinder]

Re: 3.5 Isuzu trooper towing at 4000 rpm

That is pretty flat and I have been towing with the normal setting where I live and it is also pretty flat.<br /><br />I have used power shift and normal, and on flat roads find very little difference. Power shift helps on the hills though.<br /><br />I would give it a try.

 

[tomatolord]

Re: 3.5 Isuzu trooper towing at 4000 rpm

normally the rule of thumb is D and if the transmission is "hunting" shifting up and down then shift to 3 until you can shift back to D

 

[jlinder]

Re: 3.5 Isuzu trooper towing at 4000 rpm

I agree. The reason I leave it in D is that I very seldom experience hunting. <br /><br />It can happen a little up a hill, but I select power shift and the hunting goes away (typically the transmission also goes to 3rd gear)

 

[Nos4r2]

Re: 3.5 Isuzu trooper towing at 4000 rpm

I'm so glad my trooper's a turbo diesel stickshift reading that...I just get in it and drive...