FAQs

What shift knob can I use on a RennShift

The RennShift has a smooth round outer surface of the stick to use the original knob and crush sleeve. The RennShift stick is also drilled and tapped on the end with 3/8"-24 internal threads. This allows the installation of our optional threaded knobs, or easy adaptation of universal knobs.

Does the RennShift come with a knob?

No, because of the variety of choices, including reusing your original knob, we do not make you pay for a knob (you may not use) when you purchase the shifter.

Which stick length do I want?

Stick length is determined by personal preference, your body type, and how you sit in the car. The shorter stick places the knob as the same position as the factory shifter. The 2 inch longer raises the knob and moves it back slightly. Many people enjoy the decrease in the distance from shift knob to the steering wheel afforded by the longer stick. The longer stick can also help from having to lean when reaching for 4th gear (901) or 5th gear (915). Others find the stock height just right, or want to maintain a more original look.

How do I install the RennShift?

The RennShift is very easy to install because it comes as an assembled unit. The base plate and shifter stick have to be bolted to the main housing. Remove your old shifter and set it aside, you won't need any parts from it. ------------------------------------------------------------------------------------------------------------------------- Install the RennShift by lowering the bottom bushing into the ball socket in the tunnel until the shifter is flat on the tunnel. and the shift rod bushing bracket is nested in the rear of the shifter plate. The shifter knob should be forward of neutral as though selecting a forward gear. -------------------------------------------------------------------------------------------------------------------------- Install the two new M6 screws through the lower base plate into the shift rod bushing bracket and tighten both (lightly for now). -------------------------------------------------------------------------------------------------------------------------- Install the three M8 mounting screws that attach the shifter base plate to the floor. If side force against the shifter springs is required to align these screws, then you know that an adjustment to the alignment (at the rear shift coupler) will be required. A minor alignment may need to be performed in almost all installations. -------------------------------------------------------------------------------------------------------------------------- Tighten the three base plate screws and completely tighten the two rod bracket screws (installed previously) at this time.

How do I align the RennShift?

A note about “adjustment.” The RennShift does not have any adjustments for the shift pattern - it uses the same shifter-to-transmission alignment needed with any 901 or 915. Fortunately, the RennShift’s self-aligning spring gates allow a much easier time of creating the alignment position than the factory shifter. Tight bushings and coupler are essential for a quality alignment. ------------------------------------------------------------------------------------------------------------------------- To access the rear coupler for adjustment, remove the cover plate on the tunnel just in front of the rear seats. ------------------------------------------------------------------------------------------------------------------------- To perform alignment at the coupler, make sure 3rd gear (915) or 2nd gear (901) is still selected. Under the rear cover plate, you will find the shift coupler attached to the transmission and the shift rod. Loosen the nut and bolt that clamp the rear of the shift rod onto the splines of the coupler. These are not really splines, but axial (sometimes radial for replacement couplers) knurls to afford clamping grip. With the clamp slightly loosened, the shifter can be moved without changing the position of the coupler (and therefore the transmission). Note: this alignment is quite a bit easier with our shift coupler clamp that features a single clamp bolt rather than the factory nut and bolt combination. ------------------------------------------------------------------------------------------------------------------------- Bolt the shifter down, noting that the shifter springs self-align to the transmission with the coupler loose. ------------------------------------------------------------------------------------------------------------------------- Now the shifter can move fore and aft along the center plane while sliding the shift rod in and out of the coupler. Position the knob (or knob location if it is not yet installed on the shifter) in the approximate position of 3rd gear (915) or 2nd gear (901) – about 2-1/2 inches forward of center (this distance is not exact and will vary depending on shift throw and stick length). ------------------------------------------------------------------------------------------------------------------------ Tighten the shift coupler clamp and shift rearward into neutral. If the side-to-side alignment (radial in shift rod terms) has been maintained, the shift lever will enter neutral and back into 3rd gear (915) or 2nd gear (901) with no change in lateral position of the knob. That is, the spring gates in the shifter are aligned with the shift gates in the transmission for the center gears. ------------------------------------------------------------------------------------------------------------------------- In neutral, the upper portion of the shifter stick inside the housing (where the reverse lockout makes contact) should stand straight up when viewed from the side. If not, engage the forward gear again, and repeat the alignment at the coupler until the fore-aft position is correct (straight up in neutral). ------------------------------------------------------------------------------------------------------------------------- After checking that all gears can be selected, again check that the center plane gears can be selected from neutral with no lateral motion of the stick. This is the key to the shifter alignment. ------------------------------------------------------------------------------------------------------------------------- Note: Do not attempt to perform an alignment by holding the shifter all the way to one side or the other. There is nothing in the shifter that relates the limits of the side travel to the transmission.

Why does your headlight relay only have two relays, shouldn't it have four?

Our relay system provides the same level of redundancy as the original headlight circuit. The factory wiring runs a single wire from the headlight switch to the fuse box for the low beams, and another wire for the high beams. We tap into these two wires before they split at the fuse box to feed all 4 lights. A relay is considered at the same likelihood of failure as a switch, since the contacts are by far the most common failure mode of either device. Two 100 Watt bulbs draw about 15 amps, so each 40 amp relay has no problem with the load.

Why aren't the relays fused?

Fusing relays is not the convention for automotive wiring. The relay is considered the same as a switch - the likelihood of failure to short is extremely low compared to a load device. Our system retains the factory fuses for each individual light element. ------------------------------------------------------------------------------------------------------------------------- Note that the main battery cable runs all the way back to the starter and feeds are running all over the car including to the alternator, ignition switch, and finally back to the fuse box with no fuses. --------------------------------------------------------------------------------------------------------------------------- If fusing is desired for the power feed portion of the circuit, it would be more appropriate to apply it to the entire set of feeds with a maxi-fuse or similar. This is the method applied to many newer cars. This would encompass all the small wires currently attached to the battery positive terminal, and to maintain this level of protection you would also have to consider protecting the wires from the starter to the alternator and the B+ output from the alternator. --------------------------------------------------------------------------------------------------------------------------- There are two circuits where the factory was remiss, the gauge lighting and the AC condenser fan are loads that were not fused, and adding inline fuses to the circuits would be a good idea.

What relays are used?

The relays are the most common universal relay, often referred to as "cube" relays or "Hella" relays. Nearly every auto manufacturer has used this type of relay at some point, from fuel pumps to horns, so replacements can be found anywhere with little trouble. A 4 or 5 prong version can be used as a replacement. We deliver our sets with Tyco (Bosch) 40 Amp relays, which should last the life of the car.

How long does it take to get my order?

Orders usually take 3 to 5 business days to prepare. Because of the many variations and sometimes custom work that is added to our parts, we final assemble each package after the order is placed. Shipping is by USPS Priority, so transit time is 2 days to most US locations.

Will you ship to my country outside the US?

Yes, we use USPS Priority International to ship around the world. We can't project a transit time since customs can cause a delay. Although the packages are delivered in a week most of the time, we had one item shipped to Canada that languished in customs for 6 weeks.

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