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I have a 92 Geo Tracker with a 5 speed. The question or problem I have is that there seems to be very little difference in speed or rpms between 4th and 5th. It doesn't have a tach. so I can't see if there is any drop in rpms. It also seems that it is tacking about 4000 at 45mph. Could it be that it is not even in 5th when I shift from 4th to 5th. Also could it be that I have a automatic transmission rear end or would that have an different affect. The clutch is not slipping. :confused:
 

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That RPM is close to correct, you have a small high rev engine...

..... Philip
 

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Four grand {est}at 45 mph sounds pretty high,but with out a tach that's a guess right,.My '91 runs about 34/5 at 60 mph, with 31s
 

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It doesn't have a tach. so I can't see if there is any drop in rpms. It also seems that it is tacking about 4000 at 45mph.:
Without a tach, how do you know this? These engines are high revving, but it's unlikely that you should be doing 4000 rpm at 45mph - unless you are in 3rd/4th gear?????
When going into 5th, the rpm only drops about 500 rpm or so - it is much less than the drop between the other gears. The rule of thumb with the gearing is that in 5th gear at 3000 rpm, you should be doing about 55 mph.
 

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I have a 92 Geo Tracker with a 5 speed. The question or problem I have is that there seems to be very little difference in speed or rpms between 4th and 5th. It doesn't have a tach. so I can't see if there is any drop in rpms. It also seems that it is tacking about 4000 at 45mph. Could it be that it is not even in 5th when I shift from 4th to 5th. Also could it be that I have a automatic transmission rear end or would that have an different affect. The clutch is not slipping. :confused:
Let me ask this question...

Let's assume for one minute that what you're hearing is correct - and I say you're hearing it because you say you have no tach, which means you can only guess at the engine speed - you're going to have to live with it because that's how the vehicle was built - right?

Let's go the other way - and assume that you have unusually accurate hearing and there is little or no difference in the engine rpms - what do you propose to do about it?

This is a manual transmission vehicle - hard metal gears with finite tooth counts, no friction clutches or bands to wear or slip - what ever gear ratio you have is what the transmission was built with.

Where does that leave you? Either way you get to live with it because that it was built.

No - there is no way for the transmission to still be in 4th after you have shifted to 5th - it's physically impossible because of the way the shift mechanism works. When you push the lever forward from 4th to the neutral position, it physically moves a selector hub disengaging 4th gear - you then move the lever sideways, which moves it away from the 3rd/4th selector hub, to the 5th selector hub and then push forward engaging that selector hub with the gear.

In a nutshell, what you're doing here is questioning your ability to estimate the engine speed based upon the sound - which in my experience is not an easy task.

If it really bother you, see if any of the auto parts places near you rent tools, you need either an old fashioned dwell/rpm tester or one of the newer digital timing lights that indicate rpm - hook it up and pass the leads out the side and through the window so you can drive with the instrument connected (please tape the leads to something so the don't get caught in the fan), and verify the actual rpm in 4th & 5th gear.
 

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I have a 92 Geo Tracker with a 5 speed. The question or problem I have is that there seems to be very little difference in speed or rpms between 4th and 5th. It doesn't have a tach. so I can't see if there is any drop in rpms. It also seems that it is tacking about 4000 at 45mph. Could it be that it is not even in 5th when I shift from 4th to 5th. Also could it be that I have a automatic transmission rear end or would that have an different affect. The clutch is not slipping. :confused:
You must have 2 wd as those didn't come with tachs. The speedo/tach from 4wd trackers are a plug n play, '92 thru '95. Junkyard or ebay.
 

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Discussion Starter #7
Thanks all. I was wondering if the dash with a tack be would hard to put in, thanks Ranger for that info.. I have since look up the difference in the axle from manual too automatic, so I wonder would it help lower the rpms and would any difference in the set up like spring hangers exc.?
 

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On your vehicle the ring & pinion is what will be different, but, to avoid the cost of a diff specialist to correctly setup the preload & backlash, you could consider swapping the entire third member - unless you're like me, in which case you're going to want to replace the seals & bearings whilst you have it apart, which means paying to have it set up correctly.

If you have a 4WD, you need to change both ends.

Now the $64,000 question - what makes you think you can "out engineer" the engineers that selected the OE final drive ratio?

Selecting a final drive ratio is a compromise, and the engineers would have considered the torque curve of the engine, the transmission gearing, the tire size and the intended use of the vehicle - chances are unless you have made a significant change to one of those, you already have the optimal final drive ratio.

BTW - the automatic final drive is usually a lower gear (higher numeric ratio) - unless I'm very much mistaken, swapping the auto final drive into a five speed, with the same size tires, will take your rpms up, rather than down, at any given speed - it's a common trick used by the off road crowd to correct the gearing and get the engine back into the power band after fitting larger tires.
 
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