poor gas mileage

[tblake]

Yeah, that doesn't look good. I hate to be the bearer of bad news. Troy may know more, but looks like you may have stripped the splines off the 4th/od clutch shaft in the trans causing your trans to not go into 4th gear. Only way to repair it is to rebuild or replace.

[chrissbee77]

how much are we talking to replace or rebuild and is aamco a good place to go??

[3100]

Originally Posted by tblake

Yeah, that doesn't look good. I hate to be the bearer of bad news. Troy may know more, but looks like you may have stripped the splines off the 4th/od clutch shaft in the trans causing your trans to not go into 4th gear. Only way to repair it is to rebuild or replace.

I think according to his readings that all is good. It is normal for rpms to be higher in 3rd from 4th.
Check your wheel alignment, most people overlook this when it comes to poor mpg.

[3100]

Originally Posted by chrissbee77

how much are we talking to replace or rebuild and is aamco a good place to go??

Your trans is OK. it is going into overdrive, you can try replacing atf and filter.

from poor mpg complain you almost ended up replacing your trans, think logically, imagine bike with 5 speeds - in 3rd you have to pedal faster to go lets say 20mph and in 4th you will pedal much less to go same speed thus differences in rpm. Trust me trans is OK. that little difference from 2000 could be from normal clutch pack wear, bad wheel alignment, wind resistance, wider tires, old trans oil.

[tblake]

The thing with the 4t65e is that if the 4th clutch strips, the trans will shift 1st, 2nd, 3rd, not shift into 4th, stay in 3rd, then the torque converter will lock causing the RPM's to drop. The driver feels the RPM's drop and thinks the trans is shifting fine, even though its in 3rd overdrive and not 4th overdrive.

To the OP, I would take it on a trip, drive around town a little to get the motor and trans all warmed up, then take it on a ride on an interstate. Set cruise at 70mph and let us know what the RPM's are. RPM's at 55-60mph should be between 1500-2000, and at 70mph, should be almost exaclty on 2000rpm.

I don't even thing the stripped 4th clutch shaft will trip a DTC, but it might. Either way, you could take it to a trans shop and see what they think. Start in drive, go, you should feel the shift from 1-2, 2-3, 3-4, then you may not feel the overdrive enguage. So 3 nice firm shifts and then overdrive and RPMs should drop.

3100, if clutches wear, the trans will slip, not miss a gear. Either way, missing 4th or clutches slipping that bad would be time for a rebuild. Plus my car has needed an alignment since summer and I get 250-300 miles per tank even in winter stop and go and longer warm up times.

[BNaylor]

The symptoms vary with a stripped 4th clutch shaft. It may go into 4th - OD or maybe not. One of the prevalent symptoms that I have seen is it will shift to 4th - OD but then drops immediately to what feels like neutral and then the tach jumps up indicating over revving if you still have your foot on the gas.

Originally Posted by tblake

RPM's at 55-60mph should be between 1500-2000, and at 70mph, should be almost exaclty on 2000rpm.

[troy1]

2200 @ 60 is too high I think you may have stripped the 4th clutch shaft. Now if you want to know for sure put the car in 4th D or D with a circle around it go 60 MPH again and pull it down into 3rd and see if the RPM changes. If you have access to a scanner you can check for codes if the TCC is not working correctly you should get a P1870

[chrissbee77]

tblake:,

I took the car out again on the highway and with the cruise control set at 70 mph the rmps' were at 2200 rpm.

[3100]

your trans is good With 186K on the clock 2200rpm@70mph = good.

[tblake]

Originally Posted by 3100

your trans is good With 186K on the clock 2200rpm@70mph = good.

LOL

Since you put it that way!

[3100]

Originally Posted by tblake

LOL

Since you put it that way!