ZF 5DS-25 Ring-gear Bolts

Has anyone experienced the ring gear-to-carrier bolts loosenen in their ZF transaxle? If so, how did you detect this condition? I ask this because I've been told the low-speed clunking noise at wheel speed coming from the transaxle area in my car may be due to loose ring-gear bolts. The transaxle was built in the early '90s by RBT, so I'm unsure whether they safety wired these bolts at that time. If not, having them loosen is a distinct possibility.

Any feedback will be appreciated.

Tom

I'd have thought this to be pretty unlikely, by the time these bolts got loose enough for you to actually feel it they'd normally have got ripped out completely, that, if it happened, you'd know all about!
If it's clunking and your sure it's coming from inside the transmission it's far more likely to be the diff' that wants looking at, get it checked as soon as you can because if it lets go it'll be expensive.

I assisted in the repair of a Pantera transaxle that had a leak.That was the ONLY symptom! When the bottom plate (top plate on a GT40) was removed,ALL of the ring gear bolts had the heads broken off! The leak was caused by one of the heads getting cought between the ring gear and the cover .It broke a small hole in the cover that was easily repairable.
At a Pantera club tech meeting, Lloyd Butfoy(RBT) said that the loose bolt condition was caused by the bolts relying on the serated face that would not "dig in to" the hardened surface of the ring gear. I have personally safety wired 8-10 ZFs . None of them had loose bolts but several of them were NOS units.I have spoken with several Pantera owners who have had broken ring gear bolts.

Ron and Stuart: Thanks for your suggestions. I now have the back off the car so I can get access for removing the top cover. If the ring-gear bolts are tight, the differential is next on my list. However, if they're loose I install new bolts and safety them. Got to head off expensive damage. One this year is more than enough. I've just fnished rebuilding the Cobra's 427 side oiler after a spun bearing . . . NOS $ crank, LeMans rod and custom pistons. Ouch!

Thanks again, Tom

This is a common issue and it is highly recommended to safety wire these (there are actually kits for this) whenever one is even close to them. Here is a list that you might find helpful.

**RBT Transmissions, Roy Butfoy (ZF Service), 1920 E. Warner Ave., Suite E, Santa Ana, CA 92705, (wk)714/660-0288 660-0288 250-1798, (fax)714/660-0289

**Frank Jerome, Final Touch, 5900 East Berry St., Ft. Worth, Texas 76119, 817-496-6454

Hall Pantera, 15337 Garfield Ave., Paramount, CA 97023, (wk)562/531-2629

JB's Pantera Care, 27151 Pam Place, Moreno Valley, CA 92360

Pantera Specialists, [email protected] Home Page - Pantera Specialists EFI/ECU

DeTomaso Performance, CT, (wk)860/668-5690

Mayberry Lincoln Mercury, 4437 Lankershm Blvd., North Hollywood, CA 91602

Pantera's By Cook, 2955 Bronco Lane, Norco, CA 91760, (wk)909/278-4243, (fax)909/278-4244

**Pantera East, 7165 30th Ave. North, St. Petersburg, FL 33710, (wk)727/381-1151

Pantera Parts Connection (PPC), 645 National Ave., Mountain View, CA 94043, (wk)1-800-DETOMASO

Pantera Parts Connection in Reno, NV, (wk)702/331-7009

**Pantera Performance Center, Dennis Quella, 1856 N. Park Street, Castle Rock, CO 80104 (wk)303/660-9897 9848, (fax)303/660-9159

** These are ones that I have direct knowledge of or have been advised are top notch. That's not to say other aren't, I just have no knowledge of them.

Regards,
Lynn

PS: a search here on ZF and safety wire might also be helpful.

Tom,

Just noticed that your are in Hickory. Of course Lee Holman's shop in Charlotte could do this and, while I know that Crawford Racecars in Denver can do it, they maybe completely snowed under with their GrandAM Daytona Prototype cars. (They may also be on a well deserved vacation since the season had ended.)

Holman Automotive Inc., 9119 Forsyth Park Drive*, Charlotte, NC 28273
(704)583-2888 Fax number (704)583-2890
[email protected] | Holman Moody|
* they are no longer at the airport

Crawford Race Cars LLC.
3501 Denver Drive
Denver, North Carolina 28037
phone 704-483-8726
fax 704-483-5129
CRAWFORD RACE CARS

Regards,
Lynn

Lynn: After getting into the transaxle and find out what's amiss, I'll give Roy a call. This is the first time I've been into a ZF since campaigning a Group 7 McLaren, so it's like starting over. I need info, such as special tools and torque specs for the -2.

Looks like suppliers won't be a problem thanks to folks like you. I've been to Holman's new digs and have dealt with Lee, so I have that one's covered. Worked with H&M way back in the KarKraft days, too, but that's history. Also have contacts at Crawford, but might stop by my old buddies at Riley's first. They moved their shop from Indianapolis, but hear they may return.

Tomorrow I'll open here up. Won't be too long that I'll find out if I've lived right then what I need.

Thanks again, Tom

Gents
The contact at RBT is Lloyd Butfoy, I believe Roy was Lloyd's father and passed away a few years ago.

Ross

My wive's prayers were answered. She can now have her new hardwood floor.

The klunking noise was the lack of or loose ring-gear bolts. Six bolt heads were broken off and sitting harmlessly in the bottom of the case. The remaining bolts were just a little more than finger tight. It appears that the gears are OK. Only problem I have now is fishing out the bolt heads and removing what remains of the four that are broken off flush. I have to do this without contaminating the transmission, too. The best way of doing this is to coax each out with a small chisel. Once that's done I can reinstall the new bolts with LocTite, safety them and replace the top cover.

Sounds like you got there just in time (and are very lucky to have no damage) glad to hear it.

Woooo....lucky you. This usually results in a trashed transaxle.

Of course Ross is exactly right about Roy and his son Lloyd. I put the list of ZF guys together at about the time of Roy's passing and neglected to update the contact there. Lloyd had posted here a few times in the past (circa when Ford was testing their GT mules with RBT transaxles), but I am not aware of any recent posts.

Sounds like you are well on your way to dodging a major bullet and are very well connected so as to get everything you need to put your gearbox right. Sounds like you must be living right too, LOL! As I recall, there is a guide to doing the safety wire mod in ERA's manual. I have an old pdf version, without pictures, on the computer here somewhere; but Bob Putnam has been pretty gracious in allowing individuals to purchase his manuals on CD. You might want to give him a call as this may be one of the most succinct sources of info for a DIY repair.

I don't know anyone at Riley, but I have no doubt they are top notch people there as well. I was just soooo impressed with Max and Jan and how they are just plain "Good People" that I try to mention them at every opportunity I get. While I don't know Lee all that well personally, he has always been very cordial and helpful to me. (I have heard stories from others which indicate that he is one of those guys who either strikes you one way or the other without much middle ground.)

Regards,
Lynn

PS: Be sure to contact Ron and/or me if you get down Raleigh way. I'll be sure to do the same if I ever get over to the western side of the state. It would probably be a good time to cruise the Blue Ridge if I had my fuel delivery issues sorted; oh well, maybe next season. I love it up there when the fall colors are at peak! We usually go up around the Blowing Rock/Boone area.