HOW-TO Build Custom CV Axles for Automatic OD Transmission Swaps

1984-88 Pontiac Fiero

Disclaimer and Notes:

The information provided here is for reference purposes only.  The parts discussed here may or may not work for you depending on the placement of your engine/transmission package in the car.  Engine/transmission placement is CRITICAL to axle lengths and differs from car to car depending on what mounts are used.  Furthermore, axles that can be purchased at most auto parts stores MAY NOT WORK with these instructions because of aftermarket manufacturer's design changes.  I only use factory axles, factory axle parts, or remanufactured axles that use factory parts in my swaps and these instructions were written for use with these parts only.  I suggest you get your donor axles off of a parts car from a junkyard or other source so you can verify their origin.


440-T4 or 4T60 (non-electronic) Automatic Overdrive Transmissions using a stock Fiero engine (in stock location)

NOTE: Using stock Fiero engine mount, stock 92 Pontiac Bonneville front transmission mount, and stock Fiero rear transmission mount bolted to 440T4/4T60 mount bracket (on transmission) w/ mounting holes in cradle elongated so the mount studs line up.  Some elongating of the front transmission mount holes in cradle may also be required.  Make sure engine mount bolt holes are lined up before determining if you need to elongate any of the transmission mount bolt holes.

Driver's Side:

Passenger's Side:

4T60-E and 1997-up 4T65-E (non-HD) Electronic Automatic Overdrive Transmissions

Driver's Side:

Passenger's Side:

Concerning the INNER CV joint portion and CV inner shaft itself:

-The Fiero OEM inner CV shafts will not work with the electronic OD transmissions because they are of incorrect length.
-The some donor CV inner shaft's snap ring grooves may be spaced differently than what you will find on the Fiero parts.  Although they are spaced differently, they will still work with the Fiero CV joint components.
-If you have a 4T60-E HD transmission, you may need to use the donor inner tripot ends from the 4T60-E HD transmission you got.

1997-up 4T65E-HD Electronic Automatic Overdrive Transmissions

 Concerning the INNER CV joint portion and CV inner shaft itself...

-The HD inner CV shafts and outer CV joints will not work with the Fiero components because they are of incorrect length and are too large of diameter.
-The some donor CV inner shaft's snap ring grooves may be spaced differently than what you will find on the Fiero parts.  Although they are spaced differently, they should still work with these CV joint components.
-When the CV shaft / joint assembly is inserted into the HD CV tripot; there should be virtually NO PLAY (twisting) although the joint should smoothly slide in and out of the tripot (plunging action).


Custom Axle Building Suggestions

When building your own axles, you can use whatever CV boots you feel fit and seal the best.  The larger boot clamp must be CV shaft-specific part (to clear the knuckle) but the smaller diameter clamp can be a regular hose clamp if you don't have access to replacement small CV boot clamps.  NAPA Auto Parts sells new CV boot clamps.  Take them a set of old ones you need so they can get you the correct diameter replacements.  There is a special CV boot clamp crimper tool available you should use when crimping new CV boot clamps or recrimping used CV boot clamps.  I suggest cleaning all used components with mineral spirits and then drying with compressed air.  You can then test-fit your custom built/length axles on the car before installing the grease and boots to check for proper length.  The inner tripot bearing should not bottom out in or come close to coming out of the inner tripot end throughout all ranges of the suspension's motion.  Use NEW CV joint grease when assembling.  New CV components can re-use grease as long as no foreign material contaminates the grease or components.  When you build your axles and install them into the car the boots should look normal; that is so they don't look extended or compressed excessively.  The CV shaft needs to be able to extend and compress into/out of (plunging action) the inner CV tripot to compensate for suspension geometry during normal driving.  The CV shaft assemblies should also not bind with the car moving on the ground nor when the car is jacked up and the wheels are free-wheeling.  Also, make sure you don't have any CV boot leaks and that there is not any CV joint play when you turn the wheel back and forth.


Breaking your axles?  Need stronger inner shafts?  Check out: Provide them with your existing inner shaft and/or specs and they will build a new one using stronger material of your choice.  They can also build custom-length axles.


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revised: 4-25-2011