Gearbox Clutch CVs Sloppy gear change improving
Introduction
HarryMann: Sloppiness or just awkwardness into some gears, 1st and Reverse (and maybe 'G' on a Syncro) come to mind. Mention has also been made of not holding into 2nd, 3rd or 4th due to mis-assembly of the rear sliding bush support plate. N.B. Diagnosis between external lever and selection mechanism problems and the gearbox require careful consideration especially by those never having owned a T25 or worked on them a lot e.g. most mechanics these days. e.g. don't immediately assume an internal gearbox problem, but don't discount it either, if gears go missing!
If the gearlever travels too far towards the dash (knuckle rash into say reverse) it could be some of the adjustments or wear of parts below, but also a bent gearlever in 2WD T25s, however unlikely,check the lever first.
You might be able to correct this by adjusting the spline joint position (radially) under the centre of the vehicle, but more likely its wear....
There are several bushes and parts that wear and replacing them can improve the selection quite a bit - but saying which one is the best to try first not easy.
By inspecting and waggling the main shaft near these joints underneath, or watching as someone moves the gearlever, you can determine which is worn (more than the others).
Towards the rear, there is a plastic bush held captive by cups and a bracket off the gearbox; this supports the selector shaft before it connects to the selector arm on the gearbox. Another in the middle just fwd of a frame, against the face of which is bolted a tube and cup retainer - inside this is the central nylon bush. Directly aft of this frame is the universal joint, a plastic spider with two pins.
When reassembling the rear linkage there is a plate that bolts onto the gear box that holds the linkage in place which in the words of Aidan...
"The onion plate sandwich sits on the front of the boss on the gearbox"
If you mount it to the rear of the gearbox boss you will not be able to select all the gears! i.e. 2nd and 4th on a five speed. Or 1st and 3rd on a 4 speed
Part Nos
- 251 711 207 D Front plastic bush (hollow bellows with thin lip-seal either end)
- 251 711 207 E Rear plastic bush (late) (solid plastic bush with deep spirallic grooves)
NB. Early T25s used the 251 711 207 D part at the rear without the two protective boot/bellows, replaced by E
There are some part number changes, which I think results in always using the E part at the rear together with the bellows, early didn't use bellows and used same bush as centre-section - the D part)
- 251 711 167 F (2) Bush Bellows (rear/late)
- N 900 719 01 (2) Clips (small jubs or crimped hoseclips will do)
- 251 711 184 C (1) Bellows (front)
- 251 711 551 (1) central plastic U/J
- 251 711 291 (2) pins (central U/J)
- N 012 436 2 (4) circlips (central U/J)
- N 900 899 01 (8) O-rings (central U/J)
- 251 711 973 Sel lever (rear cup/socket arm) Petrol
- 251 711 973 A Sel lever (rear cup/socket arm) Diesel, longer
- 251 711 167E Bellows for 973 part
- N 032 331 1 Roll-pin (6x32) for 973 part
- 251 711 221 F Gbox lever (Nylon ball on arm, or onion)
- 251 798 116 A (Front cab g/lever pivot repair kit; see below)
See Gearchange - Pictures and drawings
There are rubber bellows there to prevent water/dirt ingress, which may be split. Once the front or rear shaft in these nylon bushes becomes worn more than about 30 thou (.75 mm), then 'lost motion' will be inevitable. [both shafts are nominally 2.00 cm dia. when new at the bearing area]. Replace the boots (which are not anchored to the shaft, but restrained fore and aft, fit a new bush and fill the whole joint with grease is all you can do then, other than acquire a better 2nd hand shaft (not really recommended unless yours is really grim).
General - Disassembly and re-setting
To change any of these plastic bushes requires the shaft splitting at the splined joint, just ahead of the spider, which should be scribed up prior to disassembly to maintain its axial and radial position. These spline positions determine how far the gear lever is both fore-and-aft and sideways (which also ties up with the lever travel detents in the gear lever box under the floor - the catch!). Resetting is known to be difficult (see contributions below) - the basic idea being to set the transaxle's drop arm is in neutral (verticallly downwards), and then ensure the bottom of the lever under the cab is about right within the detent stops - Bentley gives 23mm from the long flat (offside) stop to the lever's corresponding detent face. Sorry - a picture here is worth a 1000 words ;-)
Some use white grease for these joints, as the VW polygrease is a fortune (£25), others use moly grease (light would seem best) and I've used Mobil blue (waterproof bearing grease) a few times - whatever, a waterproof grease is best (Castrol CL Gen Purp?)
Front (cab) section
Also, as the gearlever goes through the floor, its pivoted in a complicated set of bushes and springs - a repair kit is available:
- 251 798 116A (VW £40+, Brickwerks cheaper). This can also make a big difference.
Photo How-To, Fitting gearlever ball-joint repair kit
Also see Forum Discussion below
Centre-section
Remove the protective tube to watch the spider uj - these can develop wear, but usually after other bushes are causing more 'lost movement'. If you do the spider, make sure the pins (retained with circlips) are located fully in their detent slots when re-assembling - if they aren't they'll rotate and wear the steel forks rather than the plastic spider - requiring a new shaft!----
Good luck, not a 5 minute job, nor that cheap if the front needs doing.
Rear-section
I'd start with the rearmost sliding bush assembly and ensure that is not sloppy, grab the shaft and see if there is any play, shoving it up and down or watch it (clonking sideways maybe?) as someone waggles the gear lever. To replace this, you have to remove the rearmost cup-lever (that moves the gearbox selector arm's ball). Drop the plate that secures the bushing to the transaxle (2 bolts) and then there is a roll-pin (6mm x 32mm, NLA) that has to be driven up into the cup to remove the lever-cup from the shaft. Then you can slide the whole rear shaft bushing off the arm to clean, inspect, change the bush, re-grease and re-assemble. If the shaft itself is badly worn and pitted, you'll obviously never quite get it free-of play, but a new bush, grease and general clean-up will make a difference and prevent it wearing worse for quite a while. The late bush (E) and boot design requires a clip (crimped pipe clip is OEM fit) on the shaft about 15~16 cm from the end of the shaft. Pre-loading the back-to-back boots with water-resistant grease helps to keep out moisture and road muck in future. Then clean out the cup thoroughly, there is a nylon insert inside that needs removing to retrieve the roll-pin. Reboot the arm, fill the cup with grease and when bolted back up in place, lip its boot over the cup securely, even jub clip it the cup/socket arm.
Update: More and more I'm noticing that at the rear, selection problems can occur due to the cup/socket arm 'rocking' on the shaft (mainly back/fwd), despite being secured by the roll-pin. This will give more and more back/fwd gearlever travel (and maybe a loss of precision sideways too), until one or other gears might not engage.
Diagnosis: Under the rear of van, hold the socket/cup arm firmly with one hand and push/pull the rear selector shaft, feeling for any lack solidity in it's fitting to the ally socket arm, giving any rock - it should not rock on the shaft 'at all
Fix: Remove rear shaft (release gbox bracket (2 bolts) and then pop out one of the central UJ pins (secured with an 'e' clip, don't loose!), the horizontal one is easiest to get pin in and out of; take to bench and vice; clean grease out of cup; clean end of shaft; remove plastic bung at bottom of cup; support bottom of cup well on a suitable solid surface so that the roll-pin can exit underneath; using a 5 or 5.5 mm straight shank drift (roll-pin is 6mm x 32mm), drive out the pin downwards, being careful not to catch the drift on the hole in the shaft or burr the edge of arm; carefully drive the arm off the shaft, despite being sloppy, it will tighten up, tape evenly all around or manually twist off, do not distort it
Clean up: Inspect cup for hollowing out and excessive wear (will be worn, but if heavily lipped a new one will make a difference, the ball (onion) on gbox lever can be changed too); re-assemble with new cup or reverse cup on shaft to crate tighter fit, use a new roll-pin, if very sloppy use loctite bearing fit; align accurately first, then drive roll-pin through cup and shaft (ensure shaft/cup is aligned vertically correctly i.e. bend in shaft goes correct way); replace plastic cup, grease; replace.
Forum Discussion
Finding the spline setting
BlingPanzer: Be under no illusions... it's an arse of a job. Quite frequently, it will be half a spline out. Slacken-off the pinchbolt a tiny amount until you can only just move the rods against each other with a pair of molegrips; otherwise you'll probably turn it too far. Trial and error is the order of the day; it took me 5 attempts to get mine "something like" after a linkage rebuild, and 2nd gear still isn't quite right 100% of the time.
Point 1: You can't adjust the linkage just for one gear. Whatever you do will affect them all.
Point 2: Just a thought, but if you haven't stripped the linkage down and gear selection used to be OK, then it's down to component wear and not adjustment. Mark the linkage to preserve its position where it is now, then replace all the bushes; believe me, time spent marking the linkage and putting it back excactly to that setting when you've completed the job will pay dividends later!
Mocki: always find the best way with linkages is move it only 1/2 as far as you think you oughta, and adjust from the front backwards, ie, start at the stick end, if you have renewed the back end the floor plate may be out by some
OLD_ONE: When having trouble into Reverse or 1st Press down harder when selecting
MetalMickey: This is how I find the basic spline setting for the gear selector rods
It's not hard but very touchy if its not just right. The main thing is to have neutral in the g/box = neutral on the stick, this sets the fore/aft on the splined joint and you can mark it, wrap tape round, whatever.
This should not need changing, next pull it out of the splines and have the gearstick in 2/3 position, (from underneath you will see the fork on the bottom of the stick riding either side of the ally guides), move the gearbox end arm to the rear( 2nd gear) and get your mate to move the stick forward into 2nd, as he does this slowly re-engage the splines up to the previouse mark and nip it up.
You should now have a gettable neutral and 2nd/3rd. Then try the other gears.
I do it all from underneath with vicegrips on the bars to help...
Lost 1st and/or reverse?
lhd: Pull out the spare wheel remove the linkage casing and check that the 10mm nut has not come loose (front selector shaft pivot pin bolt), that's what happened to mine a couple of months back and I lost first and reverse.
See Also/Links
Also see:
