overdrive conversion spit mk4

[DaveKent]

can anyone tell me if the overdrive mounting plate (3 rail box with j type) should be bolted directly to the chassis in place of the non overdrive plate, or on top of it, leaving the existing mountplate spanning the chassis?

[hypoid53]

You really need the correct mounting platform TKC 1407 for the 3 rail j type, however you may be able to adapt your D type (148897) with a couple of new holes! If you are converting from a non-overdrive box then you will need the platform. It will fit using the existing 4 mounting holes on the chassis.

[DaveKent]

yes i have the correct mounting plate for a j type, the original box in the car was non overdrive. the problem i'm having is a terrible vibration at speed. the prop is new and balanced to high tolerance and the driveshaft ujs are new too. i just wondered if i'd got the angle wrong by mounting tkc1407 directly to the chassis, but i guess from your reply hypoid53 that i haven't.

[DaveKent]

so no-one knows????!!!!!!!!!!!!!!!!!!!!!!!!!!!   Little bit worrying with all these spits with overdrive conversions!! oh well RBRR here we come.

[Richard B]

xyv wrote:

so no-one knows????!!!!!!!!!!!!!!!!!!!!!!!!!!!   Little bit worrying with all these spits with overdrive conversions!! oh well RBRR here we come.

I don't think there's many 3-rail boxes with J'types around. Although I was planning on going down this path......

[neilnaz]

XYV have you checked that the propshaft UJs line up? (Thread on the Darkside about propshaft angles and someone mentioned that the flangesshould be in line.)
Have you checked your engine mounts. It could be that there is a slight tendancy for the drive-train to resonate and the engine mounts are a little sloppy?

I can't think of anything else but I am not the worlds most experienced mechanic. I got my O/D conversion done by Max at Totally Triumph for £reasonable

best of luck!!!!!!!

[DaveKent]

neil, because i have the naff strap drive prop, which i now think is the root of all evil, it is only possible to assemble the flanges in line. i'm after a sliding spline prop now to try to sort the vibration. all engine and gearbox mounts are new, too.

[DaveKent]

Richard_B wrote:

I don't think there's many 3-rail boxes with J'types around. Although I was planning on going down this path......

yes richard, a much nicer change with the 3 rail i think. 73/74 spits had these boxes if o/d was specified