auto box

[Brasco]

why is it that after I go for a ride with the range, the enganging of drive on the auto box gets a bit harsh , with a cling noise every time i give it the gas pedal?? the hi- low is giving me a hard time to engage/ disangage too ..

[FridgeFreezer]

The clonk on engaging drive is the input gear to the L230, the splines inside wear out due to lack of lubrication. The answer is to fit a new cross-drilled one from Ashcrofts.

[paintman]

You say a 'cling' noise. Where does this sound like it is coming from? If it is towards the front of the box/back of the engine then it could be a cracked flexi plate (the plate that connects the flywheel to the torque converter).

A clonk from the back of the box is indeed likely to be wear in the gearbox to transfer box output shaft. The good news with the ZF auto box is that this is a stub that fits onto the gearbox & is £30 (FTC5090 in 'Miscellaneous') from http://ashcroft-transmissions.co.uk as opposed to the manual gearboxes which require a strip to replace the mainshaft! Remove the round plate on the back of the transfer box (I'm assuming it is an LT230 ?)& check the splines. You will of course also need a new transfer box gear (input gear in the same section)

Changing range could be lack of lubrication in the linkages. Many are never put into low box & are often seized solid. Worth selecting on a regular basis to keep everything moving so when you DO need it you can select it.

Can also be due to tickover too high.

You may find it helps to select a gear in the main box, put it back into neutral & then try the transfer range change again. Certainly works with mine. LR suggest engaging Park, applying the brakes, then whilst maintaining pressure on the Transfer box lever in the direction required move the main gearbox selector rapidly back & forth between Park and Reverse until the gear engages.

[richardthestag]

You don’t say what autobox / transfer box you have.

My old 92 RR Classic with BW transferbox used to chippup on overrun at speed. I.e. 60mph and lift off the throttle and it would go chippup chippup chippup etc. It confused me because it sounded like it came from the depths of the passenger footwell. I initially thought some relay was playing up but couldn’t find one. The car ran ok otherwise then one day 20k after I bought the car and as I was pulling away from traffic lights BANG! The engine was still running, there was a horrible grinding noise and the car started to roll backwards. The transferbox had lunched itself, I never established what part of the box had gone put proved it because when the hi-low lever was in neutral and the gearbox in drive there was no noise. There was absolutely no drive through the transferbox but it did sound nasty. I bought another 2nd hand transfer box and fitted it over a weekend. Drive came back and chippup went away.

A mate of mine had a Triumph 2500 automatic that the flex plate had broken on. That made a clicking noise until one day it lunched itself and broke the bell housing!! I helped him strip that and it was a mess. The flex plate had cracked halfway between the crank bolts and the TQ bolts right the way round. I guess that when it finally said enough was enough the weight of the TQ no longer attached to the end of the crank allowed it to vibrate and knock a lump out of the bell / TQ housing. The rest of the car was quite nice (this was a long time ago) we found a scrappy 2000 complete with manual o/d box to put in but never quite managed to finish it before mate lost heart and sold it as a project.

This chap had a broken flex plate on a Rover p6 this is what they look like;

HTH

Richard

[FridgeFreezer]

A clonk from the back of the box is indeed likely to be wear in the gearbox to transfer box output shaft. The good news with the ZF auto box is that this is a stub that fits onto the gearbox & is £30 (FTC5090 in 'Miscellaneous') from http://ashcroft-transmissions.co.uk as opposed to the manual gearboxes which require a strip to replace the mainshaft! Remove the round plate on the back of the transfer box (I'm assuming it is an LT230 ?)& check the splines. You will of course also need a new transfer box gear (input gear in the same section)

I thought the ashcroft input gears had deeper splines to engage on the non-worn portion of the input shaft? I've known a few people put a new drilled gear onto a worn input shaft and it's lasted absolutely fine.

[Mark90]

The splines on the original spud shafts on the ZF boxes is too short to take the longer cross drilled input gear. So if fitting the cross drilled gear you need to get the spud shaft from ashcrofts even if your original one is not too worn.

[paintman]

You might indeed get away with just the longer shaft, but while you've got it in bits.....

[Brasco]

the box is a rr classic 1989 model. it has the D, 1,2,3 so i am assuming its a 3 speed box.. i apologise for my lack of technical words but this auto box is very new to me and i am still getting used to it, especially the reving of engine thing etc..

the thing is that it sort of works a bit harsh only after a long drive.. it is as if when the oil gets hot that it starts misbehaving..i checked the long dipstick inside the engine bay and the oil level seems fine, so i am assiming the gear mentioned above is the culprit..

thanks for all the feedback to all concerned.

[FridgeFreezer]

You have a 4-speed auto, ZF4HP22 box. The 3-speed ones were much earlier and only have D-2-1 on the shifter.

Fact for the day: The 3-2-1 selection stops it from changing up higher than that number, but it will still change down lower (quite a lot of people think it locks it in that gear, which it doesn't)

[Brasco]

so i have a 4 speed.. that shows how up to date on auto gearboxes i am...

thanks for the info..

but still have to try and identify the cause , as the clonk on the props is getting louder everytime i engage gear... still i am trying to figure out why uit does not do it when i engage gear on a cold engine...

will keep youi updated..

[richardthestag]

I thought they all clonked on the props. my RRC with 46k on the clock clonks slightly when moving from reverse through drive with my foot on the brake pedal. the 180k snotter that preceded it clonked very loudly indeed but once clonked it was fine until changed direction again. if you get my drift.

The autobox in the high mileage snotter wasn't that great so I did a fluid and filter change, world of difference and smooth a peanut butter (non crunchy stuff). IIRC service shedules state gearbox filter and fluid changes every 30k, more frequent if you go deep wading i.e. the next day sort of thing.

Also worth checking that the UJ's on the props are in good order I saw one where the yoke was slapping around inside an empty end cup. It was so knackered that all the needle rollers in the bearing had fallen out. That'll clonk quite a lot!!!

as already said high / low could just be down to lack of exercise. while you are doing the filter change get a can of oil with a long spot and work on the ends of the rod that connects the high low knob! to the transfer box. It is a right PITA when the pin drops out of the knob end <snigger> as it is sooo difficult to get too.

HTH

[bishbosh]

Be wary of changing the oil on an auto box, especially if the mileage is high or oil change interval unkown. Have a look on Ashcrofts website if you don't believe me!