L4N71B TRANNY

General information about the first-generation Nissan Maxima in the US. What was the Datsun 810 became the luxury leader Maxima in the US in 1981.

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benboodoo
Posts: 4
Joined: 8 years ago

L4N71B TRANNY

#1

Post by benboodoo » 8 years ago

hi im new to this : can somebody help me with my l4n71b transmission? i went to do a engine wash and forgot to put the tranny dipstick back , when i got back it worked for a couple days and stoped , i send it to the repair shop and when it got back it was not the same ; i went back to repair shop and these people dont no what is the problem, so came home and took it down got the pan out and there was fragments of the band in there , went bought 1 put it on and mount up fill oil and start , i in d and nothing was moveing i put in r same nothing, went and tighten the band it started to move after several adjustments it worked a little better 2 days passed and it started to get tight while driveing, when letgo the throttle it stoped like brake was on, a little while after it started to work again , i try adjusting again and nothing seem to b working, it cost me alot of cash already, im trying, cuold u please tell me how can i adjust these bands so it can work normal?

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asavage
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Location: Duvall, Wash.
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#2

Post by asavage » 8 years ago

I'm not an expert by any stretch, but my understanding is that if you get significant water in an automatic transmission, all friction plates must be replaced. The water destroys the frictions.

Seals, bearings and such should survive OK if the water doesn't remain in the trans for very long.

This was a problem that used to crop up every so often when a transmission's radiator tank cooler sprung a leak and got antifreeze in the trans.
Regards,
Al S.

1982 Maxima diesel wagon, 2nd & 4th owner, 165k miles, rusty & burgundy/grey. Purchased 1996, SOLD 16Feb10
1983 Maxima diesel wagon, 199k miles, rusty, light yellow/light brown. SOLD 14Jul07
1981 720 SD22 (scrapped 04Sep07)
1983 Sentra CD17, 255k, bought 06Jul08, gave it away 22Jun10.

benboodoo
Posts: 4
Joined: 8 years ago

L4n71b tranny

#3

Post by benboodoo » 8 years ago

yeah k, i got a used 1 at a reasonable price i put it on myself but for some reason its not working like it should I swiched modulator frome both but it
still shift too fast, is there anything i can do to solve that prob ?

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asavage
Site Admin
Posts: 5329
Joined: 14 years ago
Location: Duvall, Wash.
Contact:

#4

Post by asavage » 8 years ago

It upshifts too quickly (at too low of a speed)?

The first thing that comes to mind is too much vacuum at the modulator valve at the transmission. The amount of vacuum there is controlled by a valve that's mounted on the injection pump, with a little adjustable linkage.

You might want to read more about this in this post. Take a look at the vacuum schematic:

(click on image for larger)
Image

The vacuum line from the vacuum pump probably has a small orifice, and the valve on the IP bleeds off vacuum to the air filter housing. If the line to the air filter housing is plugged, or the valve on the IP is stuck shut, there could be too much vacuum reaching the modulator valve on the transmission.

You'll want to use one of these to check vacuum at the valve on the IP, and possibly at the modulator on the transmission.

Image Image


These things are cheap to buy, even new. Google "fuel pressure tester vacuum" and you can find a list of them. Like these:
Image Image
Regards,
Al S.

1982 Maxima diesel wagon, 2nd & 4th owner, 165k miles, rusty & burgundy/grey. Purchased 1996, SOLD 16Feb10
1983 Maxima diesel wagon, 199k miles, rusty, light yellow/light brown. SOLD 14Jul07
1981 720 SD22 (scrapped 04Sep07)
1983 Sentra CD17, 255k, bought 06Jul08, gave it away 22Jun10.

benboodoo
Posts: 4
Joined: 8 years ago

#5

Post by benboodoo » 8 years ago

ok I will get that guage today and follow instructions let u no what happens.
THANK U ALOT ill get back to u.

benboodoo
Posts: 4
Joined: 8 years ago

#6

Post by benboodoo » 8 years ago

hey thanks alot for ur help i did what u said and u were right !! my tranny workes realy good now, I got called out to work now and everything worked out just fine and in time for my job, thank u again!!!

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