# 87 v6 A/T Wont shift in overdrive



## spilsnthrils (Apr 3, 2009)

Hello all,

I have a new problem with my 87 Nissan pick-up it wont shift into overdrive and 1st to second is hard shift. 2 to 3 is fine and 3 to 4 is fine. Once I get 4th gear the RPMS will go to 4000 and it will never 
shift to OD or 5th gear. This is kind of a drag as top speed is about 50MPH at 3000 RPM.

I have checked fluids and they are fine. A fluid looks and smells real clean. truck 
has 162k miles on it and runs good. 

I believe this transmission is the E4N71B.

I am not sure where to look next so any help in diag would be much appreciated.

Spils


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## zanegrey (Dec 5, 2005)

i know of no 87 nissan truck with a five speed automatic transmission..


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## spilsnthrils (Apr 3, 2009)

So this truck maxs at 55MPH @ 3000RPM? 65MPH is at 4000 RPM this seems way to high to me. I swear I felt 4 shit points but maybe I am wrong. 

This does not explain the hard shift from 1st to second. If I shift manual from 1st to second it is smooth.


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## zanegrey (Dec 5, 2005)

you should really only feel 3 shift points..

you could do a filter change but thereis not alot you can do ..
the e in that nomenclature number is for electronic..

the computer controls the shfiting..


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## spilsnthrils (Apr 3, 2009)

The filter change is on my todo list.

I am starting to think maybe some one swaped the rear end with a M/T rear end.
Which would explain the higher RPMs for speeds around 65MPH. I'll need to figure out the ID numbers for that one.

I thought this pickup had an over drive. I bought it used so who knows what has been done to it or not.

If any one could post their RPMS @65 MPH for 87 to 89 D21 with auto I would know where its supposed to be at.


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## zanegrey (Dec 5, 2005)

what tires are you running ?


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## spilsnthrils (Apr 3, 2009)

31 inch 10.5 R15

This is what the truck has on it from original owner.


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## zanegrey (Dec 5, 2005)

confirm that it is shifting into overdrive by turning the od switch on and off...


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## spilsnthrils (Apr 3, 2009)

Hey thanks for all your help I appreciate you taking the time to help me figure out this.

There is no OD switch so I am thinking this pickup only is a 4 speed and there is no OD. I can count 3 shifts: 1 to 2, 2 to 3 and 3 to 4th 

I am still digging around the net to find the OEM specs.


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## zanegrey (Dec 5, 2005)

of coarse there is an overdrive switch...

is it a column shift or floor shift ??


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## spilsnthrils (Apr 3, 2009)

floor Shift. I have seen some Nissans that have a switch on the shifter. Mine has no such switch so I would guess is computer controlled. 

I did find this Tech Wiki - L4N71B Swap : Datsun 1200 Club

which states 4 speed OD.


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## zanegrey (Dec 5, 2005)

are there any switches on the dash ?
does it have a space for the overdrive on the selector panel ( the display for the shifter)

can you put it 3 and then fouth ?


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## spilsnthrils (Apr 3, 2009)

I have hunted all over the inside for any indication of an OD switch and found nothing. There is no OD designation on the Shift Selector or console Just P R N D 2 1


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## zanegrey (Dec 5, 2005)

wow...


i stand corrected ..very strange though..


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## spilsnthrils (Apr 3, 2009)

Yah I am bit miffed too. Like I said though I can feel it shift into fourth so maybe OD is working assuming 4th is OD. This is how my mustang is with an AOD. 3 speed and 4th is OD.

My buddies pathfinder can go 65 @ 3200 RPM my pickup its like a good 4000++RPM. 
So I am starting to think the rear was swaped or gears changed. I have not been able to find the gear ratios for the rear or the A/T for that matter. If I had the ratios I could do the math and figure out the rear gear ratio.


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## spilsnthrils (Apr 3, 2009)

This guy is refering to the push button OD that I have seen but his truck is the 4 banger 
1987 Nissan D21 pickup


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## smikster (Aug 12, 2008)

befor you drop and change your fluid and filter run some trans tune in there


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## spilsnthrils (Apr 3, 2009)

I already did that did not help with the hard shift from first to second. 

Now to verify and recap I definitly feel 3 shifts 1 to 2, 2 to 3, 3 to 4 and I verified that this transmission is the 4 speed. I have no OD lock out switch and I do see the lock out solenoid but the truck shifts into 4th so I would say OD is working.

The transmission has harsh shift from 1 to 2 and the RPMS seem high when it shifts with medium throttle. Light throttle and slower progression it shifts smooth. The rest of the shift points are smooth and feel good although the 4th shift I feel a shutter / slight vibration in the rear for about 1 second and then fine I think this is the direct drive locking. I have the transmission manual for this trany and trouble shooting shows vac modulator and poor fluid condition as first to causes of the hard shift. Also could be TPS not adjusted properly. Then from there its major work.

My main concern is the 4th gear, to run at 65 miles per hour the motor is turning 3500+ RPM Is this normal for this truck?? Or has some one done something to the rear gears or possibly is the OD band slipping causing the motor to have spin more to produce grab.
Looking at the trans manual all the shift points seem to be right in the target RPM range.
Tires are 31 inch which I think is one inch bigger than stock but if I am thinking correct this would lower the RPMS. 

I have had the truck in 4x4 high and when going up steep hill that is very rough seems like trany is slipping and I have to give it more throttle to get the truck moving, feels kinda like a clutch slipping or having your foot half on the clutch peddle in an manual. I have never 4x4 in an automatic so maybe this is normal. could be just need more RPM to develop pressure and the fluid is just shot.

Truck is 1987 V6 4x4 SE


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## JoeyCall (Nov 24, 2008)

The hard shift from 1st to 2nd may be the vacuum diaphragm which is mounted next to the downshift solenoid on the driver side of the transmission. I'd check the vacuum hose at the diaphragm and intake manifold.


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## mitsuspyder (Feb 27, 2009)

if ur van comes with the power switch u can check and see if it is on the power side, if it is put it to auto, because the power tends to van shift at a higher rpm than normal and it tends to shift very hard from 1st to 2nd


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## mitsuspyder (Feb 27, 2009)

joey where exactly is the vacuum diaphragm on the transmission, if u could clarify it a little better


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## JoeyCall (Nov 24, 2008)

Driver side right above the transmission oil pan. The only one with a vacuum hose attached to it.


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## mitsuspyder (Feb 27, 2009)

nice thanks alot


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