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Gearbox/ overdrive rebuild?


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Well after buying my wife her graduation present about 4 years ago, I have recently commenced stripping down her 74 TR6 for a full restoration. California import, great car, absolutly no rust. The chassis still has factory paint on the rear sections and not even surface rust on the underside of the boot floor. My wife wants to keep the car LHD, some plan about retiring to Portugal one day! I am OK with retaining as a LHD as this as it simplifies the task hugely. Also these cars are so narrow driving as a LHD on the left is not so difficult.

 

The body is good, the trim and every piece of rubber on the car have been destroyed by heat/ ozone, but again no real problem. I managed to fire the engine up prior to dismantle and again all the vital signs are good, oil pressure and temp. The car has done 75,000 miles but appears to have been well serviced and maintained until it went off the road in 1985. As I have stripped the car down the reason for the car demise has become apparent, the main feed from the battery to the head light switch is burned out, and I mean burned out. Adjacent wires also burned through the insulation. This explains the bag of 35 amp fuses in the glove box. So definitly will need a new harness!

 

I am not sure what caused the burn out, there is some evidence of DIY work to the electrics, but also perhaps the insulation chaffed through at some point under the dash.

 

This is my second TR6 restoration, my previous car was JGP 231K referenced elsewhere in the forum as previously also owned by Michael Aspel and appearing on Antiques Roadshow, which must have been after I sold it in 2004 to a nice guy, Grahame from Sussex.

 

Anyway it's a while since I have had to farm out major work to specialists, and not sure where is best for testing and repairs to the gearbox and overdrive. My previous TR6 gearbox was overhauled by Pete Cox at his small shop near Longbridge Birmingham in the early 80's. Long gone, any suggestions on a reliable repairer in the Midlands appreciated.

 

This weekend I will pull the engine and box, remove the rear axle and front and rear suspension. Body and chassis off for paint Tuesday, so getting exciting now! I will try and post some photos when I work out how to do it.

 

Kevin

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Sound like fun Kevin, Pete Cox is still doing gearbox/OD rebuilds and has recently helped me with valuable info and spares for my own rebuild.

Yes the underdash fire is quite common I think....hence the battery cutoff switch in another post.

 

john

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Kevin,

just had my A type overdrive repaired by Overdrive Spares - Rugby (01788 540666) and gearbox overhauled by Klassic Transmissions - Wolverhampton (07801 882771) both gave a great service and I'm happy to recommend them both.

 

Ray

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Why not rebuild the transmission yourself? These boxes are not that difficult and would save a good bit of cash.

 

 

 

I have considered this, I have rebuilt several cars over the years to a high standard, however I have never rebuilt a gearbox before. Is there an online article explaining the process, tools reqiured and what to look for?

 

Thanks you,

 

Kevin

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Well after buying my wife her graduation present about 4 years ago, I have recently commenced stripping down her 74 TR6 for a full restoration. California import, great car, absolutly no rust. The chassis still has factory paint on the rear sections and not even surface rust on the underside of the boot floor. My wife wants to keep the car LHD, some plan about retiring to Portugal one day! I am OK with retaining as a LHD as this as it simplifies the task hugely. Also these cars are so narrow driving as a LHD on the left is not so difficult.

 

The body is good, the trim and every piece of rubber on the car have been destroyed by heat/ ozone, but again no real problem. I managed to fire the engine up prior to dismantle and again all the vital signs are good, oil pressure and temp. The car has done 75,000 miles but appears to have been well serviced and maintained until it went off the road in 1985. As I have stripped the car down the reason for the car demise has become apparent, the main feed from the battery to the head light switch is burned out, and I mean burned out. Adjacent wires also burned through the insulation. This explains the bag of 35 amp fuses in the glove box. So definitly will need a new harness!

 

I am not sure what caused the burn out, there is some evidence of DIY work to the electrics, but also perhaps the insulation chaffed through at some point under the dash.

 

This is my second TR6 restoration, my previous car was JGP 231K referenced elsewhere in the forum as previously also owned by Michael Aspel and appearing on Antiques Roadshow, which must have been after I sold it in 2004 to a nice guy, Grahame from Sussex.

 

Anyway it's a while since I have had to farm out major work to specialists, and not sure where is best for testing and repairs to the gearbox and overdrive. My previous TR6 gearbox was overhauled by Pete Cox at his small shop near Longbridge Birmingham in the early 80's. Long gone, any suggestions on a reliable repairer in the Midlands appreciated.

 

This weekend I will pull the engine and box, remove the rear axle and front and rear suspension. Body and chassis off for paint Tuesday, so getting exciting now! I will try and post some photos when I work out how to do it.

 

Kevin

 

 

Kevin,

 

I bought a rebuilt box with overdrive and beefed up lay shaft and bearings from Overdrive Repair Services who are just south of Sheffield. It has now done approx 21,000 miles and has been (and still is) excellent.

 

Jim

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Why not rebuild the transmission yourself?

These boxes are not that difficult and would save a good bit of cash.

 

 

They may not be that difficult but you need to do your research first to find

out the snags.

 

There are a few good gearbox rebuilders around but none to compare with

Pete Cox.

It's not just the process of disassembly and reassembly - it's knowing from

experience what is worn and needs replacing and what is not.

 

Also, remember that gearboxes are a (relative) weakness on TRs so there

are certain components that need to be upgraded.

 

The gearbox is the one component I have never rebuilt myself, nor would I.

(OK, plus the axle)

 

AlanR

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They may not be that difficult but you need to do your research first to find

out the snags.

 

There are a few good gearbox rebuilders around but none to compare with

Pete Cox.

It's not just the process of disassembly and reassembly - it's knowing from

experience what is worn and needs replacing and what is not.

 

Also, remember that gearboxes are a (relative) weakness on TRs so there

are certain components that need to be upgraded.

 

The gearbox is the one component I have never rebuilt myself, nor would I.

(OK, plus the axle)

 

AlanR

 

 

Agree Alan

 

Same here time will tell in the long run,Roy has done all my gearbox's for years and also the race and rally box's for Neil Revington good enough for me :)

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Just a quick update...tore my box down tonight [74xxx miles]. As expected, it is in excellent shape. I am going to replace the layshaft bearings for insurance and the middle mainshaft bearing as it has a small amount of slop. The counter/layshaft isn't worn at all. The synchro cups look new so I am reassembling with new overdrive mainshaft and the aforementioned items. I am adding the ex volvo j-type overdrive and a new clutch cross shaft, busings and dropping in back in. I will take some photos of the reassy process if anyone is interested.

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