1999 ford explorer rpm's

[homer]

This truck has the 4.0 litre motor.The truck runs well ,but I have noticed compared to my explorer 1992,that in 4th gear[od off].that this truck revs in 4th gear at 100km/hr,in about the 2300-2400rpm range.My old truck ran at the same speed at about 1800-1900rpm range.Keep in mind this is the sport model and seems to have alot more power overall.Any idea if this is normal?I did make sure I counted the shifts from start and there were three not counting 1st gear from start.Any help would be appreciated.Thanks.

[way2old]

Possibly you have a different gear ratio in the transmission and rear end that can cause the rpm difference.

[homer]

Thanks way2old,but the only advantage I can see is more mid range power,but on the other side I can see more fuel being used for the same distance.Would that be correct?

[way2old]

That is why you have the overdrive Thast drops the ratio to 1 to 1. Turning the OD off is for towing. Gives more power and less strain on engine and trans.

[homer]

The overdrive is off,and I can feel 3 shifts after taking off at lights.The last shift change is in and around the 70-75km/hr range.Just wondering if anyone with this same truck at about 62mph/100kph there rpm's are about 2300 or so on the highway?Thanks all

homer :?

[jgate]

Check your safety compliance certification sticker on the inside of the drivers door. and post the trans code and the axle codes.
In 92 your Trans was a A4LD and in 99 you could either have the 4R55E the 4R70 trans, and I have seen the 5R55E trans in some of the late 99 explorers.
the A4LD and the 4R55E trans had the same gear ratio:
1st.....2.474 : 1
2nd....1.474: 1
3rd....1.000 : 1
4th ...0.750 :1

The 4R70 gear ratio
1st ....2.84 :1
2nd....1.55 :1
3rd....1.00 : 1
4th....0.70 : 1

Ford had 5 different ratio differentials,
3.27--- 3.45 ....3.55...3.73...and the 4.10

[homer]

I'll check it out tomorrow and get back to you

[homer]

From what I gather from the door stickeris as follows-wb-102,brk-4,inttr-zt,r-z,axle-42,tr-d,spr-dl,9ltab-a.I hope this helps.I believe with this ratio I would use more fuel on the highway.Thanks


homer

[jgate]

According to the codes you gave me, you have a(5 speed auto) 5R55E trans with 4:10 non -limited slip diff.
In 92 the most common was the 4 speed (4R55E) trans with the 3:55 diff.
5R55E trans ratio:
1st...2.47 to 1
2nd...1.87 to 1
3rd...1.47 to 1
4th...1.00 to 1
5th...0.75 to 1

[homer]

Thanks for your reply.Any idea why I may not be getting into 5th gear?I believe that is why my rpm's are a little higher than they should be.The tranny seems smooth and shifts nicely.

[jgate]

In your previous post , you said the OD was turned off and you had 3 shifts, that would put you in 4th, with OD(lock-up) yet to go. Do you now have the OD turned on? And still only have 3 shifts?, OD (lock-up) is a very soft shift with this trans. The real reason your RPMs are higher is because of the gear ratio of the diff. you went from 3:55 to 4:10.

[homer]

I meant the od off light was turned off meaning it is now in overdrive.Just my backwards way of thinking.thanks