What gear box # do I need for my 81 Caddy?

[vwcrzy]

As topic states. I want to be able to get it to go from Point A to B and back to A without using only 2nd, 3rd, or 4th gears. So, what gear box # do I need for my 81 Caddy?

[Iowa Caddy]

vwcrazy - I think you're not getting any replies because of lack of specifics. Diesel or Gas? 4 spd or 5? Close-ratio for performance or wide-ratio for adaptablility? Low final drive for grunt off the line, or high final drive for lower revs on the highway? Small output flanges or large? Small mainshaft or large (16V)?

If all you really care about is something to get "from Point A to B and back" again, any type 020 'box from an A1 or A2, and most 8V A3's, will fit. I've heard that some later 020's don't have the correct rear mount studs, but I've never run into that.

Some of the A1 & A2 5-speed code #'s are: FO, FF, FN, FH, FJ, FM, FD, FK, 6G, 2H, 4S, 4T, 7A, 7D, 7G, 4K, 4Y, 9A, 8A, ACH, AGS, AOP, 4S, ACN, AON, ASF, ACL, ACD, AEN, AGB, 2Y.

Some 4-speed code #'s: GC, GL, GN, GP, GY, 4A, 5G, 5W, 3R.

If your current set-up is stock '81, and you don't want to change flanges or clutch disc, look for the following: FF, FO, FN, 7A, FK, 2H, 4K, ACN, ACH, AGH, AEN, ASF, ACP. If you get one of the 3-digit 'boxes, the reverse switch is different so get the later switch from the boneyard and jumper it to your wiring harness.

Hope this helps.

[vwcrzy]

quote:Originally posted by Iowa Caddy

I forgot - small output flanges or large? Small mainshaft or large (16V)?

If your current set-up is stock '81, and you don't want to change flanges or clutch disc, look for the following: FF, FO, FN, 7A, FK, 2H, 4K, ACN, ACH, AGH, AEN, ASF, ACP. If you get one of the 3-digit 'boxes, the reverse switch is different so get the later switch from the boneyard and jumper it to your wiring harness.


Iowa Caddy, I greatly appreciate it. I am new to this so pointing out all of the specifics is great for someone like me. Now I know what questions to ask.

[Iowa Caddy]

vwcrazy - I forgot to say that I think that all of the 4-speeds would have the correct small (90mm) output flanges (if you still have the stock 90mm inner CV axles). Some of the later 4-speeds MAY have the different reverse switch. I'm not real deep on 4-speed trivia, not knowing what good they are except for weight saving for autocross (and/or for the rare 4.17:1 final drive).

If you are going to change from 4 to 5-speed, see 5sp gear linkage/gate (http://vwcaddyforum.com/showthread.php?t=1619) . If you find one of the later 5-speed 'boxes with 100mm flanges, you can still use it if you swap out the flanges for the 90mm's from your existing box. Or you could keep the 100mm flanges, and change to 100mm axles. However, the OUTER 100mm CV's probably won't have enough clearance in your wheel bearing housings. You can make custom axles by replacing the 90mm inner CV's with 100mm CV's, but to do it correctly you may have to do some maching and/or add some shims. I prefer keeping the 100mm outers as well as inners. Either take a die grinder to your smaller wheel bearing housings to provide clearance, or better yet, swap your wheel bearing housings for ones that will accept 100mm outer CV's - look for later model Cabriolet's or 8V MK2 Sciroccos. BTW, this is also where you'd source your 100mm axles - and the 16V 'Rocco axles would also work. If you use the wheel bearing housings and carriers from a 16V 'Rocco, you'll also get to up-grade to its 10.1" front rotors - the 16V hub carriers won't work for you if you want to stay with your existing 9.4" discs. If you DO upgrade to the 10.1" discs, you really should upgrade the master cylinder also.

Before you install your "new" box, I highly recommend that you install a new clutch push-rod bushing, push-rod seal, and input shaft (mainshaft) seal - to avoid having to pull the 'box again because you oiled your clutch. Check the ends of the push-rod and replace it if worn. (4-speed & 5-speed pushrods are different length.)

To do a bang-up job (and have a no-leaker 'box), also replace the output flange seals - it's a BUNCH easier to do it with the 'box out of the vehicle rather than installed. Inspect the sealing surfaces of used output flanges for grooves and/or rust that will chew up your new seals. New flanges are pricey - you can get a kit from your parts store that includes a cylinder of very thin metal that fits over your bad flange(s) to give a pristine surface for your new seals to seat on. Oh yeah, you might as well replace the selector shaft seal as it's only a buck or two - although it IS relatively easy to do after it's in the car.

Let me know if gear ratios are of concern for you and I'll write up more - I don't want to overload you with details if it's not important to you. What is the code # of your existing 'box?

[vwcrzy]

Great info! This is how folks learn about our vehicles. Thank you for taking the time to teach me the above info.

[Iowa Caddy]

Glad to help, vwcrazy.

One more item - when you go to put fresh gear oil in your "new" 5-speed gearbox, it's easy - like most folks - to end up with too little lube in it. VW had a lot of warrantee work with fifth gear often going bad from low lube level, and they revised their fill spec. Most lube shops, and some dealerships, underfill by 1/2 quart.

Quoting here from the Bentley GTi, Golf, Jetta Service Manual - 1985, 1986, 1987, 1988:

"Check and fill the transaxle with the car on level ground. Place a drain pan under the oil filler plug, which is located on the left side of the trnsmission, and use a 17mm hex wrench to remove the plug as shown in Fig. 7-5.

"Allow the oil to drain off until it is level with the edge of the filler hole. If no oil flows out when the plug is removed, add oil until it is level with the edge of the hole. When the level is correct, reinstall and torque the oil filler plug to 25 Nm (18 ft.lb.). Remove the speedometer drive cable from the top of the transaxle and pour 0.5 l (.53 US qt.) of gear lubricant into the transaxle as shown in Fig. 7-6. Then reinstall the speedometer drive cable."

In plain english: Add lube through the speedometer cable hole until oil runs out of what you and I would call the overflow plug on the side. Replace that plug and then ADD another 1/2 quart (0.53 quart, if you're anal). edit -- added: Gearboxes built after 7 Sep 87 have the side level-check hole raised to the proper point to properly reflect that they are correctly filled with 2.1 quarts.

[VW caterpillar]

My son and I have enjoyed reading your reply Iowa Caddy. Thanks for the info.. as an added note I believe I read that the reverse switches ( bolt in type) are problem prone and expensive to replace.

[mortskeg]

quote:Originally posted by VW caterpillar

as an added note I believe I read that the reverse switches ( bolt in type) are problem prone and expensive to replace.


I've found the same thing, caterpillar. Between my '81 LX, '84 GTI (RIP), '87 Audi 4000 CSQ and my fiance's old 90 Jetta, none of these vehicles had working reverse lights upon aquisition. I have had good luck with switches out of the wreckers, at least the screw in type for the GC 4-speed. (Alot easier to change the 5-sp type if you have a diesel).