TR transaxle rebuild

Starting a thread on my transaxle rebuild on my 1987 TR. In the early spring I was all set to install a Newman diff in my Ferrari for piece of mind. Was going to to the job with engine in the car. I did a major service when I bought this car 7 years ago. Draining the trans oil, I noticed 3 pieces of gear teeth stuck on the magnetic drain plugs! Bad news, The car shifted fine no problems what so ever. A little noisy in 1st gear, but no symptoms. So when I checked the last service, I said major service time plus transaxle rebuild. Dropped the engine out, remove the exhaust headers, half shafts etc. You have to remove the rear headers and some studs to remove half shafts. Remove bellhousing, clutch, flywheel etc. You have to separate the engine from the trans. Made a wooden crate to support the engine while I worked on the trans. I will continue on with thread. The gold cradle supports the engine out, has metal casters. The wood crate is for engine, Very fortunate that broken teeth stuck to magnet and didn't do any other damage. 1st gear damage, 2nd gear has some pitting on the small gear. needs replaced also. Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login

 

I give full credit to Paul Newman on tips to rebuild gearbox!! Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login More gearbox photos: 1st is cradle to lift back of TR for jack stands, credit this to someone on FC. 2nd is broken teeth on magnet. 3,4,5, Newman diff and some of parts at start. 6, tools I machined to disassemble gear box. 7 is two nuts under crank flange.8,inside of gearbox. 9, set screw in oil pan area, must be removed to remove reverse idler shaft. 10, is pressing pinion or layshaft shaft out on press. OK so you have the engine and gearbox out still in cradle. You must remove all the exh. headers to get at the nus holding gearbox to engine. 19 mm nuts some have to be removed with open end wrench. Two under crank flange (see pic7), engine has to be lifted a little only to get nuts completely off. Same when reassemble. engine down a little nuts started then drop down. Remove engine with crane and put on wooden crate. Lift gearbox with crane 250lbs, put on bench. strip out diff and all covers, oil filter etc. First thing remove set screw in oil pan and remove reverse idler shaft with 12 mm bolt to pull shaft to rear of box. remove reverse gear. Remove the two spanner nuts on gearbox shafts. The mainshaft(input shaft) nut is left handed. lock the trans in 2 gears at once to lock shafts. You do not have to remove the front nut on the input shaft. Now you have to press pinion(layshaft) out of 1st before removing mainshaft (input shaft). Last photo. remove studs on bottom of box and lay on wood on press. Don't damage gearbox case. I not the best typist or photo guy, I will continue with later posts.

 

More gearbox: Remove the detent springs and balls with a magnet and shift control rods before pressing pinion shaft. Inside the control rod holes are side rod stop rollers. The main control rod (rod shifter connects to) hole is the only hole the stop rollers can and be removed from. These are two #8 in manual are rounded small shafts. This is the innerlock to keep from getting two gears at same time. Once you press the pinion shaft out a little you put the case on bench and strip gears out of case. Remove shaft a little and remove gears in steps. Remove pinion shaft (layshaft) completely first. Keep in order and refer to manual. #1 pic damaged 1st gear, #2 is gear set, #3 is 12mm bolt for extraction reverse idler shaft. #4,5 Spanner nuts and reverse idler shaft and gearbox oil filter. Last photo is wood on bottom of box heading to press.
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Romano, the propeller shaft is supposedly the fuse that saves the gearbox from further damage. Many recommend leaving the original. If you look at the prop shaft, you can see it whips under torque and rubs the diff. baffle. The amount of rubbing determines how hard the drive train was subject to. Slight polishing reveals mild abuse!

 

When I tore down the complete engine out I bagged and labeled all the bolts etc. This made for easy reassembly because the parts were back ordered for 3 months. Any way I received the 1st gear from Ferrparts in California with in a week. The 2nd gear was back ordered for 3 months from Modena Eng. in Australia. They were not in stock at the time. The new 1st and 2nd gear set from Modena Eng. have less helical and a different tooth profile from original. They look like a much better design. Modena Eng. has a reputation for building custom gear sets and transmissions for racing. Any way you have to remove the front spanner nut to replace 1st gear on the mainshaft (input shaft). 1st photo is mild rubbing on propeller shaft. 2,3,4, pic is new and old 1st gear side by side. 5th pic is second gear. By the way The gearbox has synchromesh on reverse also! Like I said in the beginning, The car shifted fine and no problems other than a little noisy in 1st gear. The result from the worn 1st gear set. So if you test drive a TR, and 1st gear is noisy, be suspect. Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login

 

Image Unavailable, Please Login Image Unavailable, Please Login Finally after receiving all the parts. Start reassembly with reverse idler gear, but leave shaft out for now. Then assemble the mainshaft or (input shaft). Then you can fit the reverse idler shaft and set screw drops in a hole to lock the idler shaft. Then assemble the layshaft (pinion shaft). Lock the trans in two gears and torque the spanner nuts. Pinion shaft nut RH, 220nm-162ft lb. Input nut LH, 200nm-147 ft lb. front nut on spline end RH. 180nm-132ft lb. Make sure everything turns freely and you can select all the gears. Install the baffle plate. Install the two side rod stop rollers #8, (pins with radius ends). Can only be installed from the #6 control rod hole. Fish them between the 2nd & 3rd, and 4th & 5th control rod holes. You can see how they innerlock between the two control rods. Only allows one rod at a time to engage. Install the o-ring seal, main control rod (protrudes to the outside of box). Take the set screw out of the case and fit the setup pin, 8mm stepped down to 6mm. This goes in to the hole in the outside control rod. This is the 1st set up. everything else is adjusted from this. It is explained in the manual. After all the forks are adjusted replace set screw with sealer. Rotate input with propeller shaft and select all the gears. Hope I didn't miss anything. Forgot to mention when putting the 3 springs and balls. You need a plate to temporary hold the springs compressed to select gears with cover off. 1st pic shows 8mm setup pin. 2nd pic shows plate for springs(blue).

 

Photos above. The black Y is tool to hold diff. while torque ring gear bolts, The aluminum shaft with key is clutch align tool.

 

I understand, I have been in many a gearbox in my past!

 

Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login [] My TR is completely finished mechanically and running and shifting perfectly. Continue on with the Newman diff install. Installed the original limited slip internals in the Newman diff. Torqued the crown gear bolts with the Y shaped too I made. I drilled and safety wired the crown gear bolts. Probably not needed, but overkill from my race car days. I took the old outer bearing race on the diff. and ground it down to make a setup race to select the shims. I machined up a series of shims to use for the trial set up. Selected the correct shims and finished the gearbox rebuild. I want to thank Paul Newman for advice on the rebuild. Replaced and repacked the CV joint boots. Before you join the engine and gearbox, a good time to replace the water pump bearings and seals and check the chain to be sure it is endless. You can't service the WP bearings without separating the engine/gearbox. When installing the engine block back down on the oil pan/ gearbox, grease the o-rings to hold them in place. start the engine down and stop about a 1/2" above to apply sealer and start the two nuts under flywheel flange. The two nuts can not be installed with the block completely down. My W/P bearings, pilot bearing, and clutch release bearings were all marginal. Replaced everything including all new seals. Replaced timing belts, tensioners, cam seals, Exhaust copper nuts etc. The car does not leak any fluids now!