auto transmission question

[Archie]

Hello fellow Nissaners!!!!!

Great vehicles-I have had many trucks 86 thru 90 for my old delivery business and every one of them gave me excellent service...

My current problem is my 86 with the 4lnb(?) automatic trans is finally getting tired. After 300,000 miles the trans is shuddering under load. It shifts fine and doesn't really slip, but shudders.

I am going to give it a good flushing with clean fluid and new filter.

 

Are there any adjustments (bands, etc)I can make while I have the pan off??

 

There was some dark material in the bottom of the pan, but not much considering that it has been a long time since I last changed the fluid.

Also, should the trans need a rebuild, is it hard to do?? Does it require any special tools???

I appreciate any and all suggestions

THX....Archie:)

[datzenmike]

It's probably an L4N71B, V6? They are not really re-buildable by the home mechanic... too complex. Drain and re-fill the tranny, then remove one of the rad coolant lines and idle the motor. Check every few seconds and top up through the filler tube. This will circulate new fluid into the torque converter and expel the old out the coolant line. When the fluid runs out nice and clean, you're done. Change the filter and clean the magnet in the bottom of the pan too.

 

There is a brake band adjustment but I only have the one for the 3N71B and it's too hard to describe where it is and the 4 speed auto may be different anyway. You could take to a tranny shop but I don't trust any of them and you would be lucky to get it back without having to spend $1,200 on 'repairs'. If you got a manual for your specific car that describes the adjustment, might be worth a try.

[Archie]

Thanks Mike for the reply. I will go ahead and do the flush thing. I have a tranny shop I trust for a rebuild but I don't want to spend $1200+ on the truck. I be selling the ole girl soon.

Funny I was going to pm you on this. I had seen some of your earlier posts and figured you new your trannys.

THanks again....:)

[datzenmike]

I'm still learning my trannys... you can't spend any time here on Ratsun with out accidentlt learning somthing:D

 

I re-read your post (86 truck) so it might be a D21 Hard Body and have the optional L4N71B 4 speed auto. If not then you must have an L3N71B auto. It has a locking torque converter and isn't a true 4 speed.

 

On the right front inner fender near the hood hinge will be an aluminum plate with the Modle # and such printed on it. Near the botton it will say Trans/Axle. Just to the right of that will be either L4N71B OR L3N71B (and then an axle code like H37)