New (to me) ZR1 with Trans Problem?

[csx4350]

I recently bought a 1990 ZR1 with 22k on the clock. The car runs & drives very well, very tight and with the exception of the rear speakers everything works as it's supposed to. One thing I noticed was a transmission whine, but I have a large collection of 60's & 70's muscle cars and tranny whine is common on the straight cut gears in old trannys so it didn't worry me. I took my mechanic for a ride last night, and his first words were that the transmission input shaft bearing is whining and needs to be replaced. I was already a bit worried about the clutch, it seems to be engaging awfully high in the pedal throw, but there's no slipping. I could really do without the bearing being trashed though.

My questions are:

Is a transmission whine normal or is it indicative of a problem with the ZF6?

Does the ZF require a specialist to work on it or can we do the bearing ourselves?

I've been reading here about using the Castrol TWS for trans lube. My assumption is that the car has the original lube in the trans & diff, both of which I intended to change ASAP. Is it possible that changing the lube will quiet the noise down? What is the trans fluid capacity?

How about the clutch, I assume the high engagement isn't normal. Any recommendations on a bulletproof replacement?

TIA

John

[rhipsher]

The input shaft pilot bushing needs to be replaced. I've removed my transmission 3 times on my 90 until I found out that the reason I was breaking TB was due to a bent clutch fork. It's a job but doesn't take a specialist. If your clutch doesn't engage until 3/4 of the peddle travel is let out then that's normal. If the clutch engages 1" off the floor board then you have to worry.

[mike100]

Some of these gearboxes make a lot of noise. I've had one of each- my current black label ZF in my 91 has always been fairly quiet, but I had a real whiny one in my old 95 LT1 car. The 95 actually shifted better, it was just a noisy one.

[scottfab]

...snip...

My questions are:

Is a transmission whine normal or is it indicative of a problem with the ZF6?

Does the ZF require a specialist to work on it or can we do the bearing ourselves?

....snip....

How about the clutch, I assume the high engagement isn't normal. Any recommendations on a bulletproof replacement?

TIA

John

Whine may be the input shaft/gear itself. It was on mine.
Likely both the shaft and input bearing but I'll never know for sure now.
Did both after the whine continued after replacing the bearing..

The ZF6 work can be done yourself but you need patients and as I recall there are three things easily effed up. You need a 20ton or so press for any syncro work.

Capacity is a bit over 2 qts (I'm not near my FSM) but you just keep adding till it want to run out the fill hole.

Clutch engaging high is a good thing to me. Better that than low.

[Paul Workman]

The 90 (black tag) ZF does have straight-cut gears, and they do whine a little, especially in first gear. And, I'm a little skeptical of bearing issues with only 22k miles; dang thing is hardly broken in!

Bill Boudreau is "THEE" ZF guru, ZFdoc.com (ZFdoc.com)and on his web site he recommends the Castrol TWS 10W-60 synthetic which might be all that is needed.

And, I too had the same question re the clutch release position on my 95 Vette, and Bill told me then that was normal, and if it was otherwise, that would be a problem.

Well, obviously, with only 22k on it, it has done its share of resting. Resting has a way of being very hard on seals, and bearings (drying out), etc. so I'll stop short of declaring phooey to a bearing issue. I'd want someone who has an early Z to test drive it and let you know what is normal or not.

In the mean time, do you hear it whine in higher gears? And, does it whine when decelerating with the clutch out? Either of these might be indicative of "something" not quite right. I'd want to check the trans oil level, and as you indicated, changing that would be the first thing to do after checking the level and see if that makes a difference. Again...bearing after only 22k??? The things that make ya say "Hmmmmm...."

Good luck with the easy stuff. If you pull the trans, you could benefit from the C-beam plates that Bill sells, if it doesn't already have 'em (for easing the process of removing and realigning the C-beam, if nothing else!).

P.

[SteelBlueZR1]

Change to Castrol from GM Synchromesh fluid completely eradicated the first gear whine in my 91 ZR-1. Just do it and the difference you'll notice in quietness and easy shifting.

[PhillipsLT5]

If original trans fluid you are more than due, just change it, see if it gets quiet

[csx4350]

OK, I changed the trans fluid to the Castrol TWS and the noise is still there. It was actually over filled, when I pulled the fill plug lube came pouring out. I made a few observations on the test drive. Understand that due to too many firefights my hearing isn't great any more.

It whines in neutral, but stops when I push in the clutch.

It whines on acceleration, but gets much quieter (or possibly even stops) on deceleration.

It whines in first through third, but appears to go away (or at least gets much quieter) in fourth and above. I was working really hard trying to keep the road and exhaust noise down listening for it but couldn't hear it.

[DarkAngel]

OK, I changed the trans fluid to the Castrol TWS and the noise is still there. It was actually over filled, when I pulled the fill plug lube came pouring out. I made a few observations on the test drive. Understand that due to too many firefights my hearing isn't great any more.

It whines in neutral, but stops when I push in the clutch.

It whines on acceleration, but gets much quieter (or possibly even stops) on deceleration.

It whines in first through third, but appears to go away (or at least gets much quieter) in fourth and above. I was working really hard trying to keep the road and exhaust noise down listening for it but couldn't hear it.

i have same pbl with mine (1990 17000 miles on it)
whines in neutral but stop when i push the clutch and in first through third
i guessed it was normal 'cause i have a black tag ZF
and i read that it was "normal"

changed trans fluid recently with amsoil and gears passed without any pbl except that noise

[gbrtng]

PM me - I'm in New Braunfels and can take a look ...
Glenn

[WVZR-1]

PM me - I'm in New Braunfels and can take a look ...
Glenn

That's the real "diagnostics" for issues, recruit or in this case except the offer of an "experienced owner/operator" for evaluation.

[FU]

PM me - I'm in New Braunfels and can take a look ...
Glenn

THE San Antone guy's will take good care of you :thumbsup:

[LancePearson]

My 1991 just has some gear train noise that sounds almost like a whooshing sound up behind the radio when driving. With the relatively square cut gears and the cavity just above the tranny getting some sound into the hollow behind and below the radio it just gets transmitted a little. I can put microfiber folded cloths up on the center console and up the dash slightly and cut it to 1/3 of the noise but I changed fluid when I got it, made sure it shifted smoothly with good synchro, etc. and have now decided I like the sound. I even when I redid the radio put some interior insulation in on the plastic dash support pieces. Sound still there. I think it's pretty endemic in them with these transmissions as far as I can tell. No fluid leaks, no shift issues, clutch works well, all gears go up and down smoothly and car runs like a scalded dog so I quit worrying about it. I drive it with the targa top in the back and off anyway so when I get going a bit you don't hear much anyway...there's a fair amount of wind noise when you slip into three digits pushing it up the on ramp...

[tccrab]

The early "Black Tag" ZF6's are noisy, it's because of the straight cut gears as mentioned earlier by Paul.
My original Black Tag ZF6 in my '90 used to almost sound like a turbo charger in first and second gear at WOT.
I wound up replacing it at the early age of 10k miles because of 2nd and 3rd gear synchro problems. Seems the previous owner or someone in his employ liked to practice their speed shifting and wasn't as good as they thought they were.
The very first time I tried to speed shift at WOT into second I heard the most terrible grinding you can imagine.
I actually found a '95 Blue Tag ZF6 for cheaper than it would have cost to box up my '90 Black Tag and ship it to the ZF Doc for repairs.
The Blue Tag ZF6 is much quieter than the old Black Tag. Hardly any gear noise at all.
My advice is to wind up the car in first gear to say 7500rpms and slip it into second and side-step the clutch.
If it don't grind, you are good to go.
;-)

'Crabs

[ALZR1]

I recently bought a 1990 ZR1 with 22k on the clock. The car runs & drives very well, very tight and with the exception of the rear speakers everything works as it's supposed to. One thing I noticed was a transmission whine, but I have a large collection of 60's & 70's muscle cars and tranny whine is common on the straight cut gears in old trannys so it didn't worry me. I took my mechanic for a ride last night, and his first words were that the transmission input shaft bearing is whining and needs to be replaced. I was already a bit worried about the clutch, it seems to be engaging awfully high in the pedal throw, but there's no slipping. I could really do without the bearing being trashed though.

My questions are:

Is a transmission whine normal or is it indicative of a problem with the ZF6?

Does the ZF require a specialist to work on it or can we do the bearing ourselves?

I've been reading here about using the Castrol TWS for trans lube. My assumption is that the car has the original lube in the trans & diff, both of which I intended to change ASAP. Is it possible that changing the lube will quiet the noise down? What is the trans fluid capacity?

How about the clutch, I assume the high engagement isn't normal. Any recommendations on a bulletproof replacement?

TIA

John


A few years back I needed A tranny so I bought A reman blue tag from A dealer for I think $1100.I installed it and the first thing I noticed was A whine
from the input shaft bearing,I ended up returning it to the dealer.A couple of months later I get A call from the same dealer saying that they are selling it to A scrap guy and if I wanted to buy it from him,so I agreed to purchase it
for $250.00
I bring to the shop knowing that this transmission made noise I disassemble
it and found that cluster gears where burnt/dark as if it overheated and the other thing I didn't like about it were the gears and how the meshed.
So I changed out the cluster gears and different transmission housings
same bearings though.

So if you take out the transmission check out the gears and the cluster gears.


AL

[tomtom72]

:o I would just make mention of a TSB that was issued some time during the later part of the 90 model year or perhaps early into the 91 model year relating to customer complaints about whining when in neutral. The factory determined that all of the 90's and some of the 91's(?) had an actual roller bearing type pilot bearing. ( in stead of the bushing that most of us are familiar with ) The solution was to replace the roller bearing pilot with the fluted bushing type and they said the noise in neutral would cease.

The whining when in gears 1 thru 4 is related to the fact that the gears are straight cut vs beveled. However my black tag zf6's gears noise ( whine) decreases as you go up thru the gears, 1st being the loudest for sure. I'm not sure why that is but I suspect that rotating speed of the next 3 gears being less has something to do with it?? But it is noisy! Plus 1st is something like 3.59(?) so it spins quite fast. Remember our transmissions were actually truck transmissions ( 5 spds to start with, where they added 6th & reverse in the extra case behind the main case ) so I should think that less attention was paid to acoustics being that it was intended for truck usage? I have 66k on mine and the noise is the same now as the day I got the car, second owner at 7400 miles. At issue with using a zf6 is that it was designed to be in a truck. Lower operating rpms. GM didn't have a manual trans division any longer so they had to go out side to get a trans that would survive the T/Q from both small blocks. I can tell you for a fact that if you go thru a series of Esses up above 5k rpms in 2nd or 3rd for a long enough distance the whine is as loud in those gears as it is in 1st at say 20 mph in my car anyway. At above 6K rpms it absolutely sounds like a turbine. I have a 'test place' with about 10 or 12 Esses that I like to do in 2nd @ 6.8k and the sound is sublime! Just keep an eagle eye on the first three gauges; the first two being of extreme importance. :)

One other note I would add as a fwiw. I change the Castrol every year or at 9k miles which ever come first. ZFDoc has the results of a test of the TWS Castrol vs I think GM fluid on his site. At about 12k miles the Castrol is down to about 38% lubricity remaining, the GM stuff was even less! That's why I do the yearly or 9k....okay I am somewhat abusive to my equipment, so I take out an insurance policy. :o

:cheers:
Tom

[scottfab]

I guess I'll repeat what has been repeated 5 or so times.
The early ZF6 (so called black label) were noisier. Some gears
were cut differently, it was based on a truck tranny. The early
ZF6s handled more torque than the later "blue label" ones. etc etc.

I noticed discoloration on gears when I rebuilt mine when
replacing the 3rd syncro but then I noticed everything was discolored
as well.

There is "noise" then there is "noise".
As the early ZF6s wear they get much louder.
The initial noise, while noticeable, is not deafening so as
to impede hearing the song of the LT5.
At some point it does.

wow $250 for a ZF6 with whine. score.

[csx4350]

Just a quick update, at the suggestion of gbrtng I took the car to Corey Henderson who's only about 20 to 25 miles from me. He drove the car and said the noise is perfectly normal, and the car is 100%. That's a class act, you know you've found an honest tech when he tells you he doesn't want any of your money.

I'm going to let him do some preventive stuff like injectors & coils, but other than that the car is great.

Thanks for all the input.

[Paul Workman]

Just a quick update, at the suggestion of gbrtng I took the car to Corey Henderson who's only about 20 to 25 miles from me. He drove the car and said the noise is perfectly normal, and the car is 100%. That's a class act, you know you've found an honest tech when he tells you he doesn't want any of your money.

I'm going to let him do some preventive stuff like injectors & coils, but other than that the car is great.

Thanks for all the input.

Nah... The "Right of Passage" requires you to pull your own plenum, at least once. ;) Swapping injectors and coils is as good a reason as any!

Congratz on your Z! Cory be da man 4 U! And, welcome to the :cheers:

[tccrab]

Yet another example that "The Brotherhood of the Beast" is alive and well.

'Crabs