[gm_2001se]

I've got a 2001, v-6, 4x4.

When cold (I know the solution to that ), it is VERY difficult to upshift from 1st to 2nd. It is difficult to shift from 2nd down to 1st all the time and at any temp, unless nearly stopped.

By "difficult" I mean that it it simply won't go from N to 1st or 2nd without waiting so long that the road speed has fallen to the point that a) 2nd gear is too high (upshift -> 2nd ) or b) the truck has stopped (downshift to 1st).

The only things that help the upshift are:
- double clutching on the upshift (weird, but it works, perhaps the layshaft decels more quicky then the engine, hence the need for a big blip-?)
- +/- slamming the clutch pedal down very quickly and making the upshift gently bet very (with a very slight crunch)

and the downshift:
- attempt at a double clutch (30% success rate)
- letting the clutch out ever so slowly while easing it into gear (with a few 'gentle' sounding clunks
- coming to a full stop

It's easy and smooth between all other gears. Downshifting from 3rd to 2nd is flawless.

83k on the clock, I bought it at 80k, and it exhibited this naughty behavoir before and after the trans oil change. I was not able to test-drive it cold, shame on me!

Thanks for any ideas or info on similar experiences.

Coincidentally, or not, I'd test-driven a '97 4x4 p/u which shifted nicely except for completely shot synchros on 2nd.

Thanks

 

[fusionfronty99]

all manuals have a stop to prevent from going into first gear when moving... its so that if you miss 3rd gear you dont go into first and blow the motor when downshifting

ohh and as for hard to go into second, i have that problem too, its the syncro going bad, dont worry about it, just be gentile

 

[gm_2001se]

1st<-->2nd Shifting

I never knew about the 1st lockout, I'll stop trying!!! :crib:

Thanks for the info.

 

[OnlyOneDR]

all manuals have a stop to prevent from going into first gear when moving... its so that if you miss 3rd gear you dont go into first and blow the motor when downshifting

ohh and as for hard to go into second, i have that problem too, its the syncro going bad, dont worry about it, just be gentile

This is completely not true. I do not know of any transmission that has a "lockout" for this. There is a 5th/Reverse interlock in the transmission.

The reason it is so difficult to shift into 1st is because of how fast the input shaft has to be spun up to engage while the vehicle is moving faster than it would normally do in that gear. The synchros just cannot develop enough friction to make it spin that fast without you having to jamb the shifter. But trust me, it will go.

As for the OP's question, if they changed the fluid they probably put the wrong stuff in there. These transmissions use GL-4 only. Most shops will put GL-5 in thinking it is "better" somehow than GL-4. GL-5 will has sulfur and will destroy the soft metals in the transmission (including the brass synchonizers). Even if you get GL-4 they rarely have the correct weight. There have been dozens of posts about this on here.

My suggestion is to immediately get synthetic GL-4 in a 75W90 or 75W85, flush and re-fill. That should fix most of it.

 

[Q451990]

I had similar behavior on my '97 HB. Difficult 1-2 shift in ambient temperatures of about 40F or below until the truck warmed up to normal operating temperature. I was guilty of putting GL-5 in that transmission as well... a true GL-4 is difficult to find locally.

I now have 5 quarts of genuine Nissan MTF sitting in my garage for the Frontier. It has about 58,000 on the odometer. I don't think it's been changed yet, so I'm going to try to do that for the next change.

For about $9/qt, it was just easier to order it with some other parts vs. trying to find something locally.

Heath

 

[2019Frontier]

I have an '04 I bought new and have experienced the same thing since day 1. I waited for it to break-in for a couple thousand miles, then changed to Redline (synthetic & very good stuff). This had absolutely zero effect on the shifting.

The truck now has about 75k on it and the second batch of Redline (which btw is about the same price as the dinosaur oil from the stealership). Over time, the shifting, which was never very smooth across the board, has improved a slight amount, but the 1-2 shift never has. If it is outside (usually in garage) and it is very cold out, you cannot shift it at all if you try to just start and go (which I try never to do, if I can help it!).

Once warm, the trans shifts just Ok. It is very important to GUIDE the shifter and not force it. If you put a little pressure on it and match engine speeds, it will go in smoothly almost all the time when it feels ready. If you try to force it, it will clunk/crunch. This is true in all the gears. Even if careful, you can feel it "kick" into your hand some of the time...

Nature of the beast, I can only assume. If it goes 300k like that, I will be happy. If you are trying to drive this thing fast, you are barking up the wrong tree anyway!

As a side-note, I changed all the fluids in the truck to synthetic except the brake fluid. The best effect I had, aside from the engine being CLEAN and decreasing startup clatter, is that the front axle automatic hubs now engage and disengage extremely easily. You just touch the clutch in revers and CLICK, it disengages, instead of the 10-20 feet it used to need...

 

[Delta]

Odd, my 2004 4 cylinder 5 speed manual, even when cold, shifts flawlessly from 1st to 2nd. Also, at very low speeds it will go back into 1st fine. Course, I rev-match on all downshifts...

 

[gm_2001se]

Thanks!

Thanks 2004Frontier and Delta.

Yep, no point in driving this thing fast.

I believe that the manual trans is a different unit for the 4-cyl than for the V-6.

My brother-in-law explained that the practical difference between the 4-cyl and V-6 versions of many small trucks is the amount of noise! Not sure if he's right, but the fuel consumption sure is different.

 

[2019Frontier]

I believe the transmissions ARE different between the 4 and 6 cyl.

The 4 cyl engine, I believe, is 143 HP and the 6 cyl is 180 HP. The really big difference is that the 6 cyl has a much broader torque curve, with a higher peak, as well (202 lb-ft versus 154). The peak also occurs at a lower engine speed. What this means is that the more you load the engine, the less it's "pulling" ability is effected. This load can be from vehicle weight, wind resistance, cargo, trailer, etc. Although the 6 cyl is not very fast and also does not get wonderful mileage, it is also not overly affected by loading (within the published limits). I have the heaviest version (which was not offered with the 4 cyl), which is the CC, long bed, 4WD, 4x4. This is 4350 lb, curb weight (and believe it or not, the 5 speed is not lighter than the auto - that is the biggest manual trans I have ever seen). The regular cab, 2wd 4 cyl is 2911 lbs. That is a HUGE difference.

I have had an entire partially disassembled wooden playset in the back of mine (god only knows what that weighs, but it was sitting on the helper springs). I have also had 5 people in there, totalling about 770 lbs, plus an entire bed full of crap, including firewood, driving up mountains in the Catskills. In no case did the engine ever feel strained and I was able to accelerate FAIRLY normally. I am sure that in such a case, the 4 cyl would be really straining, if not falling totally on it's face.

I have never towed with the truck, so can't really say how it handles that.

Anyway, does anyone know what the deal with the trans shifting is and if there is a mod to correct it?

 

[Delta]

4 Cylinder is the FS5W71C, V6 models is the FS5R30A, atleast the 2004's according to my service manual.

 

[gm_2001se]

all manuals have a stop to prevent from going into first gear when moving... its so that if you miss 3rd gear you dont go into first and blow the motor when downshifting

ohh and as for hard to go into second, i have that problem too, its the syncro going bad, dont worry about it, just be gentile

Yep, I've gotten past any stop or lockout into 1st by doing the occasional well-timed double clutch, so I'd conclude that either there is no lockout or that it's shot on my truck.

BTW, I've just adjusted the clutch play from something in excess of 25mm to about 15mm, and it is much, much easier to shift from 1st to 2nd when cold. It's still not truly easy, however, so I'm guessing that the layshaft decelerates much more quickly than the differential shaft (once in neutral, with thick, cold oil) and will still need a quick double-clutch with a blip on the throttle to get +/- re-timed. Kooky, but it works every time. I'll look into syth to see if I get the results cited elsewhere.