Syncro - Testing
From VW-Tech
New to Syncros? Need a quick checklist when looking one over? Here's a few pointers...
1) Gearbox selects all gears (G/R and 1-4) and isn't jumping out of any gears.
2) Gearbox/transmission isn't howling, whining loudly (front diffs often have a hum/whine around 50 ish, doesn't condemn them unless its awful). Some claim not hear this even when its quite obvious!
3) Propshaft is fitted (cannot determine 4) & 5) without it, so be suspicious of this one and get it fitted before road test - if its said the prop UJs are shot then this alone is £175 ish, but cannot then test whole transmission)
4) VC is working (they eiher fail open or closed) - Main thing is not failed open (no traction) as then its not a 4WD. Try climbing up a wet grassy bank and see if fronts are pulling well, any nominal slope should get the thing working. Syncro steering on full lock on tarmac surfaces gets heavy, and slows vehicle down (drags) - this is normal to some extent. A 'stiff' VC will have this charcatersitc emphasised, a matter of judgement. 4x2 or MOT roller test can be done - see club80-90 Syncro website for details.
4b) VC replacement isn't uncommon - allow ~£450.
5) Really bad vibration between 35-45 mph is transmission vibration, either created by prop UJs shot, general tiredness in engine/transmission mounts or misalignment somewhere (mild vibration is not uncommon and doesn't condemn it)
6) Differently worn tyres front/back (1mm or more) or a mix of different makes/models would not be a good sign, indicating lack of owner care and potential transmission stress (VC life threatened or expired, potentially leading to increased gearbox wear and failure)
7) Excessive slack in transmission (throttle drop test, clunking) - indicates wear in:
Diff(s); other gearbox internals; Prop UJs; CVJs; maybe engine/trans mountings, but usually not.
7b) Clicking on full lock, forward and reverse - usually front outer CV's (the most expensive and heavily loaded CVJs);
8) Visuals - Inspect CVJ boots for splits/grease;
Transaxle and front diff drive flanges for oil leaks;
Under-run bars and front bashplate should be present and give an idea of Off-road use (don't over-react), just check that front of transaxle hasn't been impacted and they aren't seriously bent;
State of discs (thickness/wear) and rear brake backplates (give an idea of corrosion)
9) Diff-locks - Has it two knobs on central difflock control fascia? or one? (only r/h knob == only rear difflock, not so desirable but doesn't condemn it); Commonly won't work if unused/not maintained for a year or so - usually not a serious problem to fix, though can be fiddly.
NB Only test on loose surfaces, only test front difflock (lefthand knob which has a twist detent for safety) when plenty of room ahead, and at slow speed. If you find a suitable area to check VC (above) then can try them, require tell-tale light to come on, may require some relative wheelspeed difference).
10) General roadability - drives well, all gears select nicely (that'd be a good'un) including G/R requiring lever depression across gate; quiet and smooth is what you are looking for, with good clutch take up and lack of drama all-round.
Chassis/body corrosion as for a normal T25 (e.g. seams, door steps, underneath sills near front/rear jacking points)
Bearing in mind where it might have been (many haven't been off-road though, ever), it might have fared worse than a purely tarmac based Transporter...
The chassis areas to check specifically:
1] Vans, Caravelles and Campers have a rear fuel filler. This area can rust and cause problems inside the flap (the insert into the 46mm flexible hose). Where this exits onto the o/s rear chassis rail, a steel pipe runs along the top of the chassis forwards into the plastic fuel tank. Muck in the wheel arch area collects behind this tube and can rust right through it creating fuel leaks (petrol smell when brimming) and also adds to engine compartment flitch plates rusting, even the bottom of the chassis member.
2] It takes two minutes to whip out the rear tail-lights... check in both snorkel boxes, as water ingress here (from the air vent above) can get trapped and flow into the chassis member. N.B. If wringing wet in there, an MV or DJ might have ignition or fuel injection problems (ISU control unit).
3] Front and rear cross-members can fill with silt if it has been waded deeply frequently and not washed out, which'll stay damp and rust through the floor just fwd of the engine hump area.
4] Inspect the fuel tank straps, a known bad area on Syncros and the fuel pump hanging off the n/s one; the pump body can (and does) corrode badly enough to leak, another safety point... straps are expensive and a pain to fit... some make their own straps out of stainless.
5] Post '87 models are supposed to have better corroosion protection and a swathe of minor improvements/additions.
