The 4X4 Postal CamperVan Project

Last updated Jan 2019


The idea : Build a campervan, for all terrain exploring, diesel powered, based on the Kubvan.

Lots of folks have put VW Diesels into Toyota 4X4's for obvious reasons, however putting a VW diesel and Toyota 4X4 running gear into Grumman Kubvan is another story. Here is a repository of details


camper van The original Kubvan configuration included a normally aspirated water cooled 1.6 litre VW diesel and an automatic transmission, with all VW rabbit running gear. The Grumman Kubvanis an all aluminum body and frame, with the vw rabbit front wheel drive. A cool ride.

So this prohect includes : Stretch the van body 18 inches to allow for more comfortable sleeping Remove and recongure the fuel tank to allow for a portion of the floor to be lowered in order to facilitate a sitting area.
The motor is going to be replaced with a 1.9 litre VW AHU turbo diesel aand mated with a toyota 4X4 transmission. Its all going to sit on a toyota front and rear axle and suspension
We started the project in 2010 with plans to go camping the following year, yup it's 2019 and the clock keep's ticking.

2010-2018: Not in chronological order.

Spent the first two years learning about 4X4 construction, by dismantling several vehicles and have ended up with a toyota transmission, and a front & rear differantial for the project. After some debate I also settled on using the VW 1.9 TDI for the engine instead of the Toyota Diesel mostly because of the physical size of the engine and my familiraity with the VW engines  have had in the Kubvan since 1995.

Getting the frame rails and bell housing clearances sorted out. Looks like I will be building a front end frame rail that connects to the existing body frame rails. The new frame rails will provide the engine mounts, pick up the front of the leaf springs and tie in the shock towers to the body. The fire wall will need to be cut away to provide space for the bell housing.

Kubvan engien bayKubvan engine compartment showing end of frame rails and front wheel wishbone connection. The rack and pinnion steering is still on the fire ewall and still needs removing. Inside frame rail dimension 24 inches, sufficient for longtitudenal engine mounting. Will try to use existing brake system & the Toyota steering mechanisim.

Frame construction :
Kubvan toyota engine mount On the left :
Outside frame rail dimension between rails = 29 inches, just enough to pickup spring hangers on bottom of rails.
Front of body connected to rails. A beam across the front will tie it all together. New engine mounts will be mounted on inside of rails.
Kubvan front frame rail
Front rails and beam across front cut and test fitted next step is to fit the front springs and shocks. I cut the front spring hangers off the old toyota frame to reuse here.
On the right : frames ready to slide under
and connect in to the original frame.
kubvan front axle frame


The body stretch
Need 18 inches of additional interior space to make it comfortable to sleep in, we also needed some frame rails to tie the rear suspension in.
kubvan body stretch

18 inch panel
kubvan streach

Rear frame extended for longer body and
spring support
kubvan interior stretch

18 inch extension
kubvan stretched

18 inch stretch, note extrusion extension.

New Handle from a bigger Grumman body:)

Sitting on the wheels

Found a tranny, thanks Derek.

Was a bit of a challange as you need a bell housing off a different car to match up with the ACME VW to Toyota adapter plate

bell housing

With the VW engine you need the bell housing on the right to allow space for the starter motor.
Toyota 5 speed 4X4 transmission

4X4 Tranny showing power take off
vw acme adapter

Adapter plate from attached

vw engine in kubvan

Engine 1 in Bay, this is not the final engine we used. Just used for building the engine mounts and figuring out other details.
kubvan engine mount

Left side rear engine mount using original rabbit rear mount. Bolts are only for mock up prior to welding
kubvan engine mount

Right side front engine mount, from another vehicle.

Steering rod, gear box connections

kubvan stering rodThis seems to line up nicely but the mounting my be difficult. I have a mustamg II rack and pinion that others have suggested would be a better solution. It however has other configuration  problems.    

Cab, interior views

steering rod

Driver and passenger area after removal of fuel tank.
4x4 kubvan tranny

Tranny Installed, drive shaft connected to diff.
tranny mount kunbvan

Rear trannty support.


Engine ECU :

This continues to be a work in progress, but the ECU is connected, the motor is running nicely and the fly by wire throttle works as you can see from the video below. Below also you can see the Mk3 Instrument cluster working. Next step is to connect the cluster, steering column etc. I am hoping there is a tach output from the ECU, and that the oil pressure and glow plug light function correctly once the engine and ECU are connected to the cluster. ECU documentation below.

68 pin connector
Click for PDF

Original VW Jetta Mk3 instrument cluster

So this was a major piece of research and even more testing but finally, I figured it all out got all the indicator lights to work as wella s the fuel gauge and coolant temperature.
Saved for a later date will be the tachometer and odometer, in theory that should be straight forward, we shal see. The following photos for documentation.

cluster pin out
click for a PDF
mk3 cluster working under test
Finally working all lights on and gauges deflected 50%
breadboard U1 and U2 from the relay block
Cluster front guts
Checking gauges and grounds
back guts
Figure this is interesting for those that have never had one apart
back cover
Bulb configuration

An invaluable link to figure out the cluster connections: ,


LINKS:  I have found these sites and forums to be helpful along the way:

Toyota service manual downloads :

All ya wanted to know about diffs:                                 :

Shackles :       

Rivet :    Rivet Gun Notes and Riveting Tips

A great local site with very helpful people :                   

Toyota diesel:       .

Toyota drivetrain specs:

Toyota Differential ID:             

Toyota VIN number lookup and parts lists :                                           

Toyota Manuals :                                            

Drawings :      

Toyota Timeline, changes to design over the years :            

RF1A, Top shift mod :   

A really great Link about diesel conversions :                         

Another informative link about engine versions and conversions :