'94 zr-1 No Reverse😭😭 Please Help

[YungEff]

Hello Everyone.

I'm new to this forum so I hope this is in the correct place.
I've got a 94 ZR-1 that won't reverse. The car will shift into all gears fine (including reverse), but when I shift into the reverse gear the car won't move. If I release the clutch in that same gear, it just idles like it's in neutral.. All forward gears are behaving normally.

The issue started when I was cruising on the hwy in 5th gear. I started to hear a grinding sound and thought I ran something over. Suddenly the car lost power and started bogging, I immediately started to pull over to the side of the road. I went to downshift as I was slowing down and as I shifted out to neutral I realized I had no access to forward gears, so I stayed in neutral until I stopped. I got the car towed and later, the forward gears were working just fine again.

I checked the clutch reservoir and it was empty, I filled it up and took it for a drive. Everything was going fine and then I noticed that my reverse gear was not engaging.
I can physically shift into reverse and the reverse lights come on but the car will not move in that gear and also will not stall if I let go of the clutch. As if it's still in neutral.

Just hoping someone may be able to point me in a good direction of where to look. Maybe clutch or pressure plate? Or maybe it's just the reverse gear on the zf6. Just looking for some experienced advice. Thanks.

[32valvZ]

Send email to billb@zfdoc.com or call Bill Boudreau at (602) 319-6575.

This is the the man to ask ALL questions to about the ZF 6....

[oldpro]

Defiantly get ahold of Bill . I bet he says you have the start of reverse gear failure . Please don't drive the car . Call bill first and go through the problem with him first . I have had this happen to me and it isn't cheap . Good thing is if you send to Bill to fix you will have a tranny that will shift like butter and last forever

[Paul Workman]

I agree. It is, according to Bill Boudreau, :notworthy a not uncommon problem with some ZF transmissions.

Apparently, there is an inherent design lubrication issue with lubrication to the reverse idler gear. When not in use, it normally spins freely on the (counter or "lay") shaft, but if lubrication breaks down, the idler heats up and the oil film evaporates and galling begins - which causes the reverse idler gear to try to counter rotate the output shaft. (That is what causes that sudden feel of something dragging. If you don't pull over soon enough, the idler gear will weld to the counter shaft resulting in locking the output shaft and the car will skid to a stop at the rear wheels (ask me how I know)!!!


The clutch is a separate issue - not related to your reverse gear problem.

[Ccmano]

It’s the transmission. Nothing to do with the clutch pack. Early blue labels have been known to completely lock up as a result of this issue. As was said don’t drive it. Bill Boudreau is the go to guy for this. His rebuilds are legend, but pricey. Your other option is to find a replacement trans.
H
:cheers:

[YungEff]

Thanks for the replies guys, I did speak with Bill and he told me basically what Paul said above about the reverse idler gear and lubrication issue.
I could have Bill fix it, but for convenience sake it would be simpler to have the work done locally. Does anyone know if this is something that your typical transmission shop can handle sufficiently? Let me know what you guys think. Thanks.

[Paul Workman]

Thanks for the replies guys, I did speak with Bill and he told me basically what Paul said above about the reverse idler gear and lubrication issue.
I could have Bill fix it, but for convenience sake it would be simpler to have the work done locally. Does anyone know if this is something that your typical transmission shop can handle sufficiently? Let me know what you guys think. Thanks.

Can't speak for any other shop. You gonna haveta blaze your own trail on that one. But, IMO, Bill B is the standard by which all others are measured. You might say, Bill "wrote the book" on the ZF repair.

[32valvesftw]

Thanks for the replies guys, I did speak with Bill and he told me basically what Paul said above about the reverse idler gear and lubrication issue.
I could have Bill fix it, but for convenience sake it would be simpler to have the work done locally. Does anyone know if this is something that your typical transmission shop can handle sufficiently? Let me know what you guys think. Thanks.
Its been my experience that most transmission shops are swap out shops. They do not rebuild anything. So I would be very careful with those types of shops.
If I was in your shoes I would visit a couple of shops and check them out. They probably wont do the same level of work that Bill would do, though. In other words I think Bill corrects the lubrication problem so it never happens again, Many shops even if they rebuild will only do so to original spec.

[32valvZ]

Thanks for the replies guys, I did speak with Bill and he told me basically what Paul said above about the reverse idler gear and lubrication issue.
I could have Bill fix it, but for convenience sake it would be simpler to have the work done locally. Does anyone know if this is something that your typical transmission shop can handle sufficiently? Let me know what you guys think. Thanks.

Ill tell you a little story about $6800. ZF rebuild. The P.O. of my car brought his transmission to a "local guy" who said he had rebuilt the ZF transmission before. The cost of the rebuild $2800. Sounded fair enough. Once the rebuild was done, the P.O. of my car reinstalled the transmission and shortly after it began to implode. Transmission was removed again. Next, the P.O. decides to ship the ZF to Bill B...... What Bill found was catastrophic failure which pretty much ruined the transmissions case and many internal parts along with it. Parts were installed incorrectly and backwards... anything that could have been done incorrectly was. Bill identified and clearly outlined with photos, all the issues. Luckily, he had another case from car # 1111 (not sure if that was from a 90 or 91) So now the poor P.O of car 2815 had to shell out another approximate $4000. to have the job redone.Transmission was reinstalled and is living happily ever after in my 90. The transmission feels and operates perfectly... I like to compare it to a quality bolt action rifle... Moral of the story, pay me now or pay me later! Send the ZF to the ZF DOC! :cheers:

[JThomas]

Thanks for the replies guys, I did speak with Bill and he told me basically what Paul said above about the reverse idler gear and lubrication issue.
I could have Bill fix it, but for convenience sake it would be simpler to have the work done locally. Does anyone know if this is something that your typical transmission shop can handle sufficiently? Let me know what you guys think. Thanks.

I had Bill build me a transmission for my project ZR-1 three years ago. He was great to work with and the transmission operates flawlessly.

[EvanZR1]

I have not had a trans issue (thankfully), but having had to do and LT5 rebuild, I’d treat the ZF the same way. Do NOT cheap out and use someone who knows what they are doing. My advise would be either send it to Bill or find a used stock (or ideally a Bill rebuilt) ZF. Used ZF will save you some money and let a local shop do the swap, but of course you now run the risk of eventual failure on the replacement. Having said that, there are a LOT of ZFs out there in base & ZR-1 C4s that have had no issues, so used is probably an ok option. Personally, I would absolutely go the Bill route if mine ever has an issue.

[Hib Halverson]

I'm quite familiar with the ZF S6-40. Not only did I own a '95 for 19 years, but back in the day, I wrote a number of technical articles about the S6-40 which were based on a mid-90s interview session I did with GM transmission engineer, Bill Zabritski (now retired) and people from ZF North America.

I also have known Bill Boudreau for a number of years. I did a story on his rebuild work and have visited his shop in Arizona a couple of times.

Bill's business is one of only two facilities left which can actually repair an S6-40. No "ordinary trans shop" will be able to fix your transmission.

[YungEff]

I see everyone is saying that having Bill repair the trans would be the way to go. Which is probably what I'll do. Just seems like there would be more shops out there that can service this trans.

[Jagdpanzer]

From Rockland Standard Gear web site:

Rockland Standard Gear (RSG) remanufacture the ZF S6-40 transmission found in the C4 Corvettes from 1989 to 1996. RSG remans these transmissions for ZF and GM and are the only source for these parts in North America. We can also repair or remanufacture your Corvette transmission if you wish to keep your part numbers intact for collector value. We stock complete new transmissions, remanufactured transmissions and a complete line of O.E. ZF parts.

http://www.rsgear.com


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[DRM500RUBYZR-1]

Rockland Standard Gear is our "go to" source for individual parts although we have never needed a complete transmission.
Their customer service and technical support is second to none!

While you cannot go wrong using Bill B by any means, Rockland, being in New York, is certainly a valid option.

Regardless of how obscure the differential or trans part is, they come through each and every time and have for many years.

Simply good to know we have options.

:cheers:
Marty

[Dynomite]

From Rockland Standard Gear web site:

Rockland Standard Gear (RSG) remanufacture the ZF S6-40 transmission found in the C4 Corvettes from 1989 to 1996. RSG remans these transmissions for ZF and GM and are the only source for these parts in North America. We can also repair or remanufacture your Corvette transmission if you wish to keep your part numbers intact for collector value. We stock complete new transmissions, remanufactured transmissions and a complete line of O.E. ZF parts.

http://www.rsgear.com


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