Autobox thump going into reverse/drive.

R

Rumblin_Ron

New Member
After a run my auto box thumps terribly when going into reverse, and then when changing back to drive. This does not happen when the car is first started, ie when reversing out of the garage. The box changes up and down the gears on the move OK, and the oil level is correct and the oil clean. Any suggestions ?

Also, wondering if a new box is on the horizon, has anybody uprated to a 4 speed auto ?. Range Rovers and Jags have them.
 
4 speed auto is a good idea, but they're around £400 second hand, I was considering one for the v8 I just got.

Have you checked the diff ?, could be the diff once the oil warms up a bit and thins out.

Richard :)
 
Ron,
My first thought is that your idle speed is set to high - Is idle speed higher after a run? Next possibility is downshift cable out of adjustment.
Regards, John.
 
Does the transmission feel as if it is slipping?

My does in reverse, judders and slips, is worse on choke.

Do you have problems reversing up an incline? mine does.

I spoke to an Auto specialist who re-built a 'box on my other V8, and he thought that it was a simple matter of adjusting the brake bands - although these are pretty inaccessible for the home mechanic with only a normal torque wrench.

I have not had mine adjusted as daily driver and inconvenient to have it out of service.

Best advice is to go and see a reputable Auto Specialist and hopefully it is just a case of adjustment.

With regard to 4-speed auto boxes - have you driven one? Suggest you do, I have found them awful, they keep changing up and down, and never seem to know what gear they want to be in. My preference is for LESS gears not MORE!

Good luck

Gary :D
 
Gary,
You're right - If you can do 57 in first 87 in second and 117 in third why do you need any more gears!
( I refer to series 2 V8 autos of course, my 35 year old Three Thousand Five can only manage 50 in first 80 in second and 117 in third!)
Regards, John.
 
I often drive 827 auto's with the wonderfull 4 speed S4 honda gearbox. Have no complaints with 4 speeds, especially as they pull 140+mph (so I'm told !)

Also aids fuel consumption too, a 5 speed manual would be preferable though, or 6 speed as is becoming common these days.

Richard ;)
 
Hey John

Empty the stuff out of the boot.....

...good for another 3 mph at least!

Then take the carpets out of the front - more throttle travel.

I not telling you what mine does....

...we have Police as members!!!!

LOL

72 mph Officer......
 
Hello Peter,
Nice to see you back on the scene!
My everyday car has a 5 speed auto (Tiptronic, i.e. posh auto) and that does 138mph (allegedly).
I must come up to Yorkshire to try out your "private test track". Regards, John.
 
Oh dear, what do I read between the lines? Have you been nicked? Have you fitted a speed limiter? Or is it just the holiday season and the quiet Welsh roads are clogged up with tourists?
Do elucidate. Regards, John.
 
Thanks guys for all the corrospondence, I should not post things and then go on holiday ! (missed Lotherton , I won't leave the bookings to the missus next time !).

When should you measure the idle speed ?, its correct by the book when in gear, but about 1000 rpm in neutral, what should idle be when in gear ?
The downshift cable gap is to large according to the book, but the gearbox changes at max revs in kickdown, so I have left alone. It does hang onto 3rd on hills etc, but is always in 1st when moving away from a standstill. There's never any slip or judder.

If my S2 is maxing out at nearly 60mph in 1st, and 90 in 2nd, it is a lot faster than I thought ! The speedo always seems to under read by 10mph (everybody drives at 50mph when I am in the Rover) and is sluggish to keep up whith the rev counter, but that's a different a problem I can live with.
The 4 speed thought is becuase after my mods it definatly pulls better above 3000 rpm, (its good below that, just stonking above) and since it wont change down from 3rd to 1st at 40 mph that extra gear would keep it in the best revs, a locked up high 4th would help the MPG too.
 
Ron,
It does sound as tho' your tickover is too high - For a standard high compression auto it should be 600 - 650 and the 9.25:1 compression ratio auto 700 - 750 in park!
May drop a little in D but should be hardly noticeable.
Max speeds in gears, foot flat on floor, are 57, 87 and 117 for series 2 so your speeds sound about right.
I do believe that one of the criticisms of the Borg Warner type 35 (and 65) was no load demand change down (that is on hills you change down using the gear lever and the gearbox will change back up when it's ready!
Downshift cable adjustment is important as regulates the road speed at which the gearbox will allow you to kickdown to a lower gear without over-revving the engine. Check your workshop manual very carefully before attemting any adjustment as incorrect adjustment can damage gearbox clutches!
I'm no expert but I have been driving V8 autos for many, many (Oh dear it's more than I think!) years. Regards, John.
 
Thanks John

I'll re-adjust the idle speed, see how it goes. At the moment its about 1000 rpm and drops to 800 in drive.
Foot to the floor it changes up just below the red line. I'm trying to keep away from adjusting any linkages, the workshop manual makes it all look way to scary !!.
Maybe the 4 speed autobox is too expensive for what you get, after all I'd have to make it fit as well. I'll stick to 3 speeds.

What I meant to say about hills is that it never changes down when going UP hills, ie it will slog away in 3rd. This is not usually a prob with the V8 up front, but on slow V steep hills it either slow slogger 30mph in 3rd, or over the top acceleration in kickdown (2nd ?), I use manual shift nowdays to overcome this. Is this normal ?
 
I've learnt with time how to use my auto geabox on my series II V8. When cold, everything is fine with nice smooth changes - up and down - however once things warm up I do get the 'clonk' when going into reverse, I also get a clonk when pottering around town in drive (top gear) say about 20 mph, and then put my foot down and it changes down into second. I find myself putting it into 2nd manually when I'm pottering around town. It pulls smoothly from zero and the gear covers all the speeds you're likely to want to do in town. I know it's not ideal, but I had my auto box reconditioned a couple of years ago, and the guy that did it says everything's adjusted as it should be and this is part of the BW65 'experience' and nothing to worry about. ???
As for kick down, I find it a bit disconcerting putting my foot flat to the floor when I want to overtake, and again I'll use the gear selector to put it in second if I want a bit of extra urge. Suppose I should get a manual really shouldn't I?
 
Ron,
Yes, I know that you meant the long slog uphill and the gearbox wont change down, I think that's called "load demand change down" and the BW33 and 65 do not have it!
Hence, change down using the stick and put it back into D when ready (or straight away and let the box decide when it will change in to third).
Regards, John.
 
Steve, If my memory serves me correctly the Police Drivers' Manual (Roadcraft) makes very interesting reading (I can hear you saying "how sad!") especially the paragraphs concerning driving with automatic gearboxes, the use of kickdown and the use of the gearstick. Worth picking up a copy from e-bay!
Regards, John.
 
I have a copy of that somewhere, my driving instructor suggested it as good reading (15 years ago), I especially liked the sections of instruction on where to sound the horn when travelling at speed !

Richard :D
 
In the years I was on Traffic in the 1960s and '70s we didn't have a manual. Just lots of good training and commonsense.
The Rover 3500S was one of the better cars. The worst was the Cresta 3300 or the Ventura with the 3300 engine. Lots of power but little else to rely on.
We had Denovas on the Rovers but it cost a fortune as they did not last. I do miss that power steering with the 2200TC.
The first cars we had fitted with the air horns were the Ford Zephyrs and lads being lads, we had a good time with them! They didn't half make the lasses jump.
 
Sorry John, semantics eh...I thought you were commenting on the "no load" demand change down, not saying that there was NO "load demand" change down ! (does that make sense).

Perhaps my box is old fashioned after all, rather than worn out. I'll adjust the idle this weekend John, and then find that book.
Whatever happened to Cresta's ? Respect Ash!
 
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