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Ahh.
Well. The ZF4HP16 is, for the most part, a reliable unit. Anything ZF pumps out is solid, BMW, Audi, Mercedes- all use ZF transmissions in quite a few of their platforms.
Now into your issue.I can almost ascertain your problem to the TRS, aka the ‘Transmission range sensor.’ What it is, is an electro-mechanical switch that actuates a type of solenoid depending on hydraulic pressure within the case. In other words, it’s what shifts your automatic transmission from one gear to the next.
The TRS is the single most problematic sensor in that transmission. They went frequently even when replaced new- until ZF came ouf with a new rev. The original parts were mostly plastic, and when exposed to extreme temps, would fail 100% of the time.. literally.The part cost 100$ in 2012. Have a qualified tech do the job, else you will ruin your unit and you won’t be able to shift from park..and eventually your vehicle wont even crank. In fact, if at all possible, give this issue to a Suzuki dealer/ shop if you have one around. I can guarantee they have done quite a few of these. If your unsure, look. As common as this issue was in the Optra, Forenza, Lacetti, Reno, Optra5, Verona, (I could go on) there were no TSB’s released in Mitchell or AllData, so there is a good chance anyone else will tell you 1.)”Thats not the problem” and you’ll end up with more problems than not. or 2.) “Whats a transmission range sensor?” This was an ‘internal’ type of thing at Suzuki/ Chevrolet.
I appreciate your advice! Yeah, one minute I’ll get in and start it and it’ll run great. I’ll shut it off, go to work for two hours, start it up, and it’ll slip then catch. It does this in all gear ranges. BTW, there is 120k miles on it but it’s a nice ride and worth a little love. Thank you much!
I’ve spotted the range switch and it’s tempting to change it myself just cause it’s so easy to get to. Is the range switch and sensor the same thing? Or is it a single unit?
I should have asked beforehand, just out of diagnostic protocol..but it is late and I’m tired..
Out of curiosity, when this issue arises, does the shift gauge change from D (drive) to a box, N, or a box with a slash through it, and if so does it blink?If so, then the ZF unit is going into what is known as “limp mode” thus preventing you from going beyond 2nd gear in order to prevent damage.
___To answer your question, it is one unit, and it is easily accessible- that is true. However, I would strongly suggest against DIY repair because certain connections need to be disconnected such as the TCM, and there is also a tiny spline that the TRS sits on, and if you replace the new part on the wrong spline, you’ll be unable to shift your car until the TCM is reset, which requires special equipment.
If you really think you can handle it, I can’t stop ya, just be aware of the risk involved.
I can certainly understand not wanting to give someone else cash for what seems to be a simple repair, it’s one of the smaller reasons I went to school to be a tech, but if you buy your own part, you shouldn’t pay more than 50$ in labor as long as you have a Suzuki shop around.Negative. I’ve watched the shift gage and it does not flash at all, even when the slipping is occurring. This tranny claims to use “fuzzy logic” and I thought that it may have something to do with it. The manual says there’s only a problem when it flashes, but as of yet no blinking indicator.
My puter froze, sorry.
Ok, so its a good thing I asked then. Forget the TRS. If anything in the electrical or diag system had a problem with the ZF, that lamp would flash, usually its a box with a slash through it and it flashes. That signifies as I stated above the “limp mode” procedure. Also, don’t worry about the fuzzy logic as thats unrelated. This ZF does utilize it, and what it is, is a system that monitors and learns your driving ‘style’ and adjust shift points accordingly. It basically takes away the overdrive or sport buttons that some vehicles use.
SO, your suffering from noise and slipping w/ out any MIL or CEL indicators.
The first thing I would look for if I were you is the transmission fluid level. This is a ‘closed system’ so what you will need is a square drain plug adapter preferably for a 3/8th ratchet. Pep boys has one here. I cannot remember if you need a 10mm or an 8mm off the top of my head BUT this is what it looks like. http://www.pepboys.com/product/details/293916/01036/
The way you check the level in this system is to get the vehicle on a flat surface, take out the fill plug, and check for any fluid leaking out. If it is just a tiny tiny trickle your good on the level of fluid. If you see nothing come out your low. I imagine you’ll see nothing come out, and I also imagine your very low, on top of needing a flush.
Now, you did say that your around 120K mi. on your Verona. Are these all you? If not, AND, if you picked it up after 60k mi. than assume that you are dangerously low on transmission fluid, as well as having a dangerously useless fluid in there now on top of it. Best practice is to always assume the previous owner neglected the fluids.
Get the fluid checked out, flush it if you haven’t done it in the last 60K miles and and we can go from there.
You got it. I know it takes a specials fluid. Murfreesboro TN. is the closest Suzuki dealer for many miles from here. It’s hard to find info on exact fluid it calls for. I’m afraid if I don’t take it to a Zuki dealer, they’ll put in any old fluid. I’ve been burned before and have a low trust threshold for shops I’m not familiar with.
BTW, I do appreciate your help more than you could know.
well, I just pulled the tranny coolant line of the tranny case and it appears to be good and full with clean bright red fluid. I think the guy I bought the car from told me he had it full once overed with tranny service. With the nice color and clean fluid, I tend to believe him now.
It ran fine to the store just now, when I came out and started it up again, it ran like crap with it’s slipping and grabbing. It’s got me puzzled if not pissed. And still no blinking indicator even in mid slip.
Transmissions can often fail without setting any DTC’s and turning a light on on the dash. It is important you check the fluid level as well as the condition of the fluid. The level is extremely important in an automatic transmission.
If the fluid condition and level are good then the next step would be to tap into the hydraulic circuit inside the transmission with a gauge and monitor line pressure in various gears. The factory service manual is needed in order to ascertain the pressure specs. This isn’t something most people are willing to do on their own as you need a gauge set made for transmission work. (But if you’re willing to do it, then go for it!)
It is very possible you have an internal transmission problem.
Yeah, I think I’m running out of DIY options. Might be time to bite the bullet and take it to the shop. Thanks for your info.
All I could add is what Xyius already said about the level.
I understand you checked the condition, but if possible, and if you haven’t taken it to a shop yet, check the actual level. The drain plug adapter is relatively cheap, although they can be pretty tough to find. If it (fluid) comes gushing out, that may be your problem right there- it’s too full. Unfortunately, this being the internet, we can’t check it out. A slipping transmission could be a hundred different things.
Another note; when you checked the condition of the fluid it should have reeked horribly (even a drop of this stuff stiiinks something fierce), and if it didn’t have a fishy odor the wrong fluid is in there. Fluid for this box is a dark dark ruby red I recall. However color/smell is only a slight indication and not useful for proof positive I.D.
This box uses either ESSO LT 71141 or TOTAL ATF H50235 (ATF is what comes shipped in the box). Take your standard transmission fluid smell and multiply it by 10. That’s ESSO 7 lol.
I’ll try to find a digital copy of the service manual for the ZF 4HP-16, note this is for a different platform (the Optra/ Forenza) so anything drive-line related will not apply to the Verona.
But with this you’ll be able to find the drain and fill plugs, figure out the amount of fluid (I think its around 4 quarts for a flush, 7 for service) etc..Here is the ZF service manual;
If i can find a service manual for the Verona I’ll reply.
One last thing/ Try to get in touch with the previous owner if you can, and ask if the transmission began to slip before or after he had it ‘serviced’. It may be the reason it was sold, or the shop that serviced it may have done something wrong.
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