gear box

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seigneur
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gear box

Post by seigneur »

hi
i have a interceptor sp,i have a probleme with the gear box,the gear 1 and 2 are defectiv,i will want change this gear box to a gear box mk3 year 71 6.3,for you it is possible or not,these gearboxes are they identical.
hello to club members JensenI am owner of a Jensen interceptor SP, I completely restored, I am pleased to revive a car outline for a case.Sincerely, Lord
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slotcarone
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Re: gear box

Post by slotcarone »

No reason why another Mopar V8 transmission should not fit. OK guys this is the American part of the car so we can use it's American terminology--Transmission! :)
1972 Interceptor III
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Dino Fritz
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Re: gear box

Post by Dino Fritz »

Superficially, the 727 transmissions between the Mk II's and the SP's are similar on the outside, and you can simply change them over, but if it's a true SP, then the transmission is (or should) be beefier inside than a standard 727 Mk III transmission. The SP and the Hemi equipped Chrysler cars have this beefier 727 transmission.

The SP inside would have a larger front (I think) drum to hold an extra clutch pack. As the drum is wider, it would also require a wider band clamp onto it, and as a result, it has a 5.0:1 lever to apply the band to the drum (Pressure = Force/Area; increase the drum area, you need to increase the force to apply the same pressure). The Jensen Parts manual gives you a hint on the different parts fitted to the SP's, and you can use this as a guide.

I'm sure that cannonball will be along shortly to add some more information, but if you're a perfectionist and want to do this properly, then there are some special parts to add (nowadays, I'm sure that there are better / stronger / lighter parts that may do an even better job than the factory originals).

Cheers, Dino Fritz
Jensens.........when does it ever end!
seigneur
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Re: gear box

Post by seigneur »

dino have reason,the gearbox for sp are different to mk3,now i will want repared this gearbox but where i will could trouved thes parts specifical,but if i not trouved this part,it is a probleme if i change by another gearbox mk3.
hello to club members JensenI am owner of a Jensen interceptor SP, I completely restored, I am pleased to revive a car outline for a case.Sincerely, Lord
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Dino Fritz
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Re: gear box

Post by Dino Fritz »

Hi,

The best place to discover the differences between the SP and normal MkIII transmission is to look at the Jensen Interceptor Mk III Parts Manual (transmission section) - they show the different parts between the SP and the Mk III's.

In the early 1990's, I know that the Jensen Car Company had some of the SP transmission parts in stock (my brother bought the 5.0:1 transmission lever) - maybe Martin Robey may have some leftover parts???

"Cannonball" on this forum may be able to help in your search for parts (and I think others here rebuild transmissions as well), but there are also the online specialists in the US like A&A Transmissions etc. that can help. Just remember that the older parts can been replaced by improved parts (e.g. the steel drums can be replaced with lighter billet aluminium parts, but just more $$'s).

If you'd like more help, drop me a line and I can scan the relevant section of the parts manual for you.

But if it all gets too hard, yes, you can just drop in a MkIII transmission into your car - but if you're a real perfectionist, you'd want to rebuild the SP transmission (assuming that it has all the correct parts inside after all of these years).

Regards,
Dino Fritz
Jensens.........when does it ever end!
seigneur
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Re: gear box

Post by seigneur »

hi dino
thanks you for your help,
the manual you'r talking about,it's the workshop manual ,its thath.
cordialy
lord.
hello to club members JensenI am owner of a Jensen interceptor SP, I completely restored, I am pleased to revive a car outline for a case.Sincerely, Lord
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johnw
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Re: gear box

Post by johnw »

Hi, no it is not the workshop manual. There is another book called "parts manual".

It could be that your transmission is not adjusted properly, or that you don't have the correct amount of ATF (transmission fluid). You need to check fluid level with engine running and car on the level after a short drive. The kickdown and bands can be adjusted.

Sorry if I am stating things that you have tried. The SP has a special transmission and it would be a shame to replace it for no good reason. Keep the old transmission if you can't get it serviced.
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Joerg
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Re: gear box

Post by Joerg »

Keep the SP transmission!!!
What ever parts you need, they are all available. The SP is much stronger inside and a very sought after item.
If you want it properly rebuild, send it to me. (Germany). Send me a pm.
I own some of the odd Jensen 8)
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Dino Fritz
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Re: gear box

Post by Dino Fritz »

Have a look at the Jensen Parts Manual, Part B "Transmission", where it will show all of the parts for H Series, J Series and Series 4 Interceptors, and the Six Pack. This will be your guide as to what parts are unique (and stronger) for the SP Transmission.

For example:
Part 55 is the Front Clutch Retainer - you can see it's a different part number for the SP because it's larger than a regular one (see Item # 63 - the SP uses 5 front clutches, whereas the regular Mk III transmission uses 4). Because it is wider on the SP, the band is also wider (see part number 54), etc.

Hopefully your SP has these original parts in them, and as Joerg says - please do try and keep the SP transmission - it definitely is stronger than the standard Mk III transmission.

If you'd like any pages scanned (or an American service manual for the 727 Transmission), feel free to PM me.

Good luck, Dino
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727 Trans Parts Illustration.JPG
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727 Trans Parts List.jpg
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