Pantera ZF question

Countach Guy · 07-02-09, 04:45 PM

Hi, I am new to this site so bare with me. I have a 351C mated to a ZF 5 speed and have run across a problem with getting into reverse. A little background here. I had the transaxle apart only for a gearing change and tested the box before installing for all gears including reverse...all good. Now that it is in the car and it will not go into reverse at all. No linkage bind I can see. Clutch seems to disengage fully as all forward gears shift nicely. I don't want to have to pull the trans out if it is something I am over looking. Any ideas?

Thanks
Ken

Jac Mac · 07-02-09, 05:03 PM

Page 7 on this Transaxle forum.....RBT stuck in reverse........, have been a couple of other threads on this as well.... think it was something about the selector position on reassembly.

Countach Guy · 07-02-09, 10:47 PM

Quote:

Originally Posted by jac mac

Page 7 on this Transaxle forum.....RBT stuck in reverse........, have been a couple of other threads on this as well.... think it was something about the selector position on reassembly.

Thanks for the link. It wasn't my problem, stuck in reverse but it did get me thinking with a post about reverse is not straight up from 1st. Again, this is a new build for me so I have a lot to learn. Short story, shifter gate cover plate was binding on the shifter not allowing it enough axial movement. Removed cover plate and hey, there's reverse!!!

Thanks for the help as I wasn't ready to drop the box out and would rather look foolish

Mike Drew · 07-03-09, 04:52 AM

Here's what a Pantera shift gate looks like. This shows the relationship between 1st and reverse quite clearly.

Countach Guy · 07-20-09, 09:38 PM

I figure I would keep this thread going on a related concern. I have a very crisp 1st to 2nd to 3rd and 4th is a little more forceful with 5th taking a pretty good pull. Is this normal?

Mike Drew · 07-20-09, 10:05 PM

Is that while underway, or stationary?

When underway, there should be no discernable difference in the shift feel/effort between any two gears. If everything is working properly, you should be able to snick the lever between gears with thumb and forefinger.

Well, maybe thumb and two fingers.

Many of the Panteras I drive have absurdly heavy shifter effort. It feels like the shift lever is sticking out of a bucket of rapidly drying cement.

The cause is normally inadequate lubrication in the trunnion bearing, the grease-filled, rubber-lipped support for the shifter rod on the chassis. There can also be excessive drag caused by aged grease in the shifter box on the side of the gearbox, and also the cast aluminum support for the gearshift lever.

The GT40 normally uses a rod end to support the shaft, as opposed to a teflon or rubber/grease affair, I believe.

In any case, when everything is properly lubricated and the gearbox is in good order and filled with decent fluid, it's a somewhat manly but by no means difficult exercise to shift it.

Countach Guy · 07-20-09, 10:23 PM

That would be stationary. I have rod ends for bushings and all greased well on the shifter rod. yeah I see it takes a little getting used to.

Countach Guy · 07-20-09, 11:07 PM

Countach Guy · 07-20-09, 11:18 PM

Julian · 07-21-09, 12:58 AM

So the ZF shifted smoothly prior to installation, you had reverse issues then removed the shift gate and got reverse. I'd have to say that the shift linkage is misadjusted in it's east-west plane and likely just needs some fine tuning.

What shift linkage do you have, Pantera, cable shift or other? If it's a Pantera (or other rod assembly with u-joint knuckles) then the routing and positioning of the support bearings (rod ends) would be fairly critical to ensure the cross gate shifter motion is translated correctly at the ZF end.

I have an upgraded rod end/machined linkage rod from Pantera Performance on my GT5 Pantera and although it makes the shifter more precise it does have more bind than the traditional trunnion bearing.

Phil · 07-21-09, 09:23 AM

Ken:
It sounds like you definitely are binding in the linkage. I would take the linkage off the gearbox and check the gear selection out, if you have that good then isolate as you go thru the linkage.
I have seen some nice looking linkage systems that bind in rotation, but only as the gear is selected. In other words the gate worked fine, but the forward/rearward motion of the shifter was causing the linkage to bind as the heim joints were hitting their limit from a high angularity. Most of the linkages I have seen don't rotate in a true circle, but form an arc in the rod somewhere, and this may be where you are having problems.
The solution may be to straighten the linkage routing, or add anothe u-joint somewhere to keep all of the rotational components from establishing their own arc as they rotate.
Of course the obvious limitations are all the interfering components and your space limitations. If you need to add another u-joint use a quality unit as a little sloppiness can add a lot of travel and poor feedback at the shifter.
As Joules said I would also check the support bearings, I use heims for those as there is usually a little movement that they will allow for without introducing any play in the setup.
Good Luck
Phil

Countach Guy · 07-21-09, 11:21 AM

Thanks guys. I adjusted the so called east-west adjustment
( modified ZF linkage) cleared up the reverse issue. I will look into the 4th/5th movement and its relationship to the rod ends. I do know before connecting the linkage there wasn't any binding and the last linkage section runs very straight to the box and not at any angle . It gives me a place to look though. Thanks Ken

Mark Charlton · 07-21-09, 01:49 PM

Ken,

I must compliment you on construction of a most impressive car. I first read about and saw photos of your now famous "basement Countach" last year and I was stunned by both the quality of your build and the details of construction.

Having spent some time driving a real Countach, I am betting that yours would actually be a nicer car to drive as well! Kudos on a fantastic job (and color choice, btw). Good luck with the shift linkage.

Mark