Thread: D2 TD5 with 6HP26 from D3,D4 or RRS

Originally Posted by AK83

ratios for the 4HP22 are: 2.480, 1.480, 1.000 and 0.728

0.728 isn't too far off from the 6 speed's 0.691.
Whether or not a std tune TD5 can pull that gearing is something I have no experience with .. but.

if you use a gearing calculator, and assume 235/70 16 tyres and a 1.000 transfer ratio, the 4 speeder gives 103.3km/h at 2000RM, and the 6 speeder gives 108.8km/h.
change transfer gear to 1.2 and again at 2000RPM; 4th in the 4 speed = 85.5km/h and 6th in the 6speed = 90.0km/h


With such a low 1st gear, you probably wouldn't need the 1.2 transfer gear, eg. for uphill starts or towing.

off road in first low is probably the real benefit to such a conversion.
if you assume the LT230's 3.32:1 ratio is maintained:
for every 1000RPM: first low in the 4speed = 4.76 k/hr whereas first low in the 6 speeder is only 2.83k/hr.

This is some awesome info. To clarify the 1.2 transfer is standard in a Disco and the 1.4 standard in a Defender. So with the ratios and tires size you mentioned the 1.2 (Disco) standard transfer case might be the go. Does your calculator allow you to work out what the RPM is at 100km/h with the 6 speed in the same example you gave?

I've looked at some pictures of the 2 autos and it doesn't appear the LT230 would bolt to the back of the 6HP26. The output appear to be a flange fitting not a shaft like the 4HP22.

I could be possible to run the transfer case from the D3 with the 6HP26, but know knows if the prop shafts would line up? That is already a major problem with the D2 front shaft when it is lifted.

Originally Posted by Jazzman

I've looked at some pictures of the 2 autos and it doesn't appear the LT230 would bolt to the back of the 6HP26. The output appear to be a flange fitting not a shaft like the 4HP22.

I could be possible to run the transfer case from the D3 with the 6HP26, but know knows if the prop shafts would line up? That is already a major problem with the D2 front shaft when it is lifted.

4HP22 was used in many vehicles in the 80's as well as in LR. Obviously the Jags, Peugeot's BMWs and suchlike would have had a different rear output than what LR required(being the shaft).

ie. here's a pic of an XJ40 Jag 4HP22 trans:
DSCF2052.JPG
note the flanged rear output.

Browsing through the WKI entry for the 6HP26, it seems there are two versions of the 4WD models of this trans.
6HP26A for VW group vehicles, and the 6HP26X for BMW/LR vehicles.

here's an image I found of a 6HP26X with a shaft rear output:
s-l300.jpg
That image is linked to an ebay image from a sale in lithuania(google image search), and the trans is out of a BMW E85 3.0 diesel.

It's a matter of having an adapter created to bolt onto the rear of the 6 speeder that uses a splined output shaft like the 4HP transmissions do for LR.
The question is how far do you go with respect to cost?

Gearing calculator I used were

OSELLA and GRIMMJEEPER

Judging by the case of the 6HP26X it doesn't have a detachable bellhousing, that really puts an end to it. The output could have used the D3 transfer case instead of the LT230 potentially. It would be closer to use the 5HP24 but even then it does look like the bellhousing holes would line up.

I'd like to see this go some where, I've just inherited a 6hp out of a 4wd territory

Originally Posted by CU55TM Disco

I'd like to see this go some where, I've just inherited a 6hp out of a 4wd territory

Keep me informed on your progress please

the second Gen 6hp21 was a low torque variant produced in china,, WIKI doesnt actually say how low---
but the original 6hp19 was good for 400nm


ZF 6HP transmission - Wikipedia

Originally Posted by johntins

Not sure if a Compushift would work.

Silly me. It has a Compushift fitted.