LT77 Gearbox noise - help
Discussion
Just bought my 4.3 Griff and noticed something which didn't show up in my pre-sale road tests - there's always a surprise in the first few days after buying a car over 10 years old I guess. The gear change is generally good if a little vague but the synchromesh seems to graunch slightly going into 5th when changing up quickly at speed. This can also happen when changing down to 2nd.The car has done 56k miles and been well looked after, is this normal for the LT77 box, do they go on for ages like this or should I plan on a rebuild soon? Hopefully you guys will say a small amount of adjustment from the top will suffice but I guess I'm dreaming.
Any help would be greatful - Cheers
Any help would be greatful - Cheers
Hi, and welcome to the wonderful world of the Pre-Cat 
I've also got a 4.3 with the LT77 box and the only thing about these boxes specifically is to select 5th before trying to get reverse or you will get crunching.
I've not noticed anything about 3rd or 5th specifically. Is there anything vague about the lever - can you get 2nd and 4th easily?
I agree with rev - you could try changing the oil. Its a really easy job to do if you get an oil 'syringe'
Have a search in the Griff forum - I posted these about changing the oil in mine recently.
I've also got a 4.3 with the LT77 box and the only thing about these boxes specifically is to select 5th before trying to get reverse or you will get crunching.
I've not noticed anything about 3rd or 5th specifically. Is there anything vague about the lever - can you get 2nd and 4th easily?
I agree with rev - you could try changing the oil. Its a really easy job to do if you get an oil 'syringe'
Have a search in the Griff forum - I posted these about changing the oil in mine recently.
Edited by Barreti on Monday 19th November 22:35
Best bet is to change the oil. Don't use the ATF fluid though - it kills the boxes and was only used as a bodge to make the shift lighter for the ladies.
Use Castrol SMS SAE 75/80 gear oil. It will be a tiny bit more difficult to change gear when the box is VERY cold (only for the first couple of miles), but the benefits in terms of longer gearbox life, cooler running, better hot shifts and less noise are immense.
Andy
Use Castrol SMS SAE 75/80 gear oil. It will be a tiny bit more difficult to change gear when the box is VERY cold (only for the first couple of miles), but the benefits in terms of longer gearbox life, cooler running, better hot shifts and less noise are immense.
Andy
Downchanging to second can crunch a bit. The way round it is to do it relatively slowly, and match engine revs to road speed (ie heel and toe).
Congratulations on buying the right Griff though - which one did you get? (link to advert maybe?)
Edited to say you'll also find it's a better change when the gearbox is warmed up - which can take 10-15 miles.
Congratulations on buying the right Griff though - which one did you get? (link to advert maybe?)
Edited to say you'll also find it's a better change when the gearbox is warmed up - which can take 10-15 miles.
Edited by griffter on Tuesday 20th November 08:19
A few years back the people from Castrol advised SMX-S for this box. When you ask them now they will tell you to use a different oil. (at least in Germany they do)
They now advice you to use Transmax-Z oil for the Rover box. I can only speak for myself, for me it made a huge difference in gear selection smoothness. I use to go quickly through first and second gear before engaging reverse, with the new oil there's no need to do that anymore. All in all a big improvement over the old SMX-S oil in my opinion.
Fred
They now advice you to use Transmax-Z oil for the Rover box. I can only speak for myself, for me it made a huge difference in gear selection smoothness. I use to go quickly through first and second gear before engaging reverse, with the new oil there's no need to do that anymore. All in all a big improvement over the old SMX-S oil in my opinion.
Fred
tvr4ever said:
A few years back the people from Castrol advised SMX-S for this box. When you ask them now they will tell you to use a different oil. (at least in Germany they do)
They now advice you to use Transmax-Z oil for the Rover box. I can only speak for myself, for me it made a huge difference in gear selection smoothness. I use to go quickly through first and second gear before engaging reverse, with the new oil there's no need to do that anymore. All in all a big improvement over the old SMX-S oil in my opinion.
Fred
But isn't Transmax-Z an ATF fluid? If so, then it ultimately will produce the same problems that using ATF fluid always does in LT77 boxes - wear and failure! They now advice you to use Transmax-Z oil for the Rover box. I can only speak for myself, for me it made a huge difference in gear selection smoothness. I use to go quickly through first and second gear before engaging reverse, with the new oil there's no need to do that anymore. All in all a big improvement over the old SMX-S oil in my opinion.
Fred
The box was actually designed to use Motul 75 gear oil - I got this straight from Ken Tomlinson who was on the design team for the box at Leyland. Early SD1s had gear oil, but (lady) owners complained that in cold weather they could not change from 1st to second for the first few miles. The switch to ATF was a bodge - and one which was to cost BL dear when box after box failed. Its worth noting that all the racing Rovers and rally cars that used the box all used Motul or equivalent.
I grant you that Transmax may be a super duper ATF, and perhaps it will not create so much wear as an older type ATF, but its still an ATF and so I'd be wary. A few miles of cold start slow shifts is a small price to pay when compared to a rebuilt box!
Andy
Thanks guys for your help, the car had a 60k service at a TVR indie dealer in August at £648. 2 litres or bottles of Castrol Dextron 3 transmission oil appear on the receipt so is it worth changing? is that oil good, bad or ok? The car had no leaks from engine, box or diff.
Link to the original add:
http://www.pistonheads.com/sales/259732.htm
Any of you down Horsham way? would be good to meet other Griff owners before I delve into such things as the pathetic heating system, boot lid ill fitting due to an over enthusiastic gas strut and the recurring request for advice on a good TVR paint shop etc
Link to the original add:
http://www.pistonheads.com/sales/259732.htm
Any of you down Horsham way? would be good to meet other Griff owners before I delve into such things as the pathetic heating system, boot lid ill fitting due to an over enthusiastic gas strut and the recurring request for advice on a good TVR paint shop etc
andymadmak said:
tvr4ever said:
A few years back the people from Castrol advised SMX-S for this box. When you ask them now they will tell you to use a different oil. (at least in Germany they do)
They now advice you to use Transmax-Z oil for the Rover box. I can only speak for myself, for me it made a huge difference in gear selection smoothness. I use to go quickly through first and second gear before engaging reverse, with the new oil there's no need to do that anymore. All in all a big improvement over the old SMX-S oil in my opinion.
Fred
But isn't Transmax-Z an ATF fluid? If so, then it ultimately will produce the same problems that using ATF fluid always does in LT77 boxes - wear and failure! They now advice you to use Transmax-Z oil for the Rover box. I can only speak for myself, for me it made a huge difference in gear selection smoothness. I use to go quickly through first and second gear before engaging reverse, with the new oil there's no need to do that anymore. All in all a big improvement over the old SMX-S oil in my opinion.
Fred
The box was actually designed to use Motul 75 gear oil - I got this straight from Ken Tomlinson who was on the design team for the box at Leyland. Early SD1s had gear oil, but (lady) owners complained that in cold weather they could not change from 1st to second for the first few miles. The switch to ATF was a bodge - and one which was to cost BL dear when box after box failed. Its worth noting that all the racing Rovers and rally cars that used the box all used Motul or equivalent.
I grant you that Transmax may be a super duper ATF, and perhaps it will not create so much wear as an older type ATF, but its still an ATF and so I'd be wary. A few miles of cold start slow shifts is a small price to pay when compared to a rebuilt box!
Andy
Chad speed said:
Don't know the car, but I spotted the advert. Looks very very good - congrats and enjoy.Chad speed said:
andymadmak said:
tvr4ever said:
A few years back the people from Castrol advised SMX-S for this box. When you ask them now they will tell you to use a different oil. (at least in Germany they do)
They now advice you to use Transmax-Z oil for the Rover box. I can only speak for myself, for me it made a huge difference in gear selection smoothness. I use to go quickly through first and second gear before engaging reverse, with the new oil there's no need to do that anymore. All in all a big improvement over the old SMX-S oil in my opinion.
Fred
But isn't Transmax-Z an ATF fluid? If so, then it ultimately will produce the same problems that using ATF fluid always does in LT77 boxes - wear and failure! They now advice you to use Transmax-Z oil for the Rover box. I can only speak for myself, for me it made a huge difference in gear selection smoothness. I use to go quickly through first and second gear before engaging reverse, with the new oil there's no need to do that anymore. All in all a big improvement over the old SMX-S oil in my opinion.
Fred
The box was actually designed to use Motul 75 gear oil - I got this straight from Ken Tomlinson who was on the design team for the box at Leyland. Early SD1s had gear oil, but (lady) owners complained that in cold weather they could not change from 1st to second for the first few miles. The switch to ATF was a bodge - and one which was to cost BL dear when box after box failed. Its worth noting that all the racing Rovers and rally cars that used the box all used Motul or equivalent.
I grant you that Transmax may be a super duper ATF, and perhaps it will not create so much wear as an older type ATF, but its still an ATF and so I'd be wary. A few miles of cold start slow shifts is a small price to pay when compared to a rebuilt box!
Andy
If the oil has been changed recently - then the really is no point changing to a different oil.
Actually the handbook for my wedge specifies S.S 80 (thats how its written in the book) for the gearbox - not ATF. I can scan it in and show it here if anyone's that interested.
I appreciate that everyone keeps referring to the Rover spec, but the Rover spec is wrong according to the man who actually designed the gearbox! As I said before, the use of ATF was a bodge to improve cold shift characteristics. High torque applications cause heat and wear in ATF filled boxes. Ken Tomlinson told me that many LT77 running ATF are so badly worn that they are beyond economic repair - especially if the car is either used to tow a caravan, or if the car uses a higher performance engine (like a TVR) which takes the box closer to it's torque limits anyway.
If it were me, and given how easy the job is to do, I would switch the lubricant.
As a matter of interest I also spoke to Richard Thorpe on this subject a few years back, and he used to make up a blend of oils for wedge gearboxes rather than use ATF
Andy
I appreciate that everyone keeps referring to the Rover spec, but the Rover spec is wrong according to the man who actually designed the gearbox! As I said before, the use of ATF was a bodge to improve cold shift characteristics. High torque applications cause heat and wear in ATF filled boxes. Ken Tomlinson told me that many LT77 running ATF are so badly worn that they are beyond economic repair - especially if the car is either used to tow a caravan, or if the car uses a higher performance engine (like a TVR) which takes the box closer to it's torque limits anyway.
If it were me, and given how easy the job is to do, I would switch the lubricant.
As a matter of interest I also spoke to Richard Thorpe on this subject a few years back, and he used to make up a blend of oils for wedge gearboxes rather than use ATF
Andy
Edited by andymadmak on Wednesday 21st November 12:04
Ditto! My V8S had similar symptoms although my 5th selection was fine. The synchromesh started to wear between 3rd to 2nd, causing a problem when changing down. I too ran the car like it for quite sometime before getting the gearbox replaced (98,000 miles). The problem grew progressively worse and would only change down from 3rd to 2nd without "crunching" when revs were under 2,500.
Steve
Steve
I'll back up andymadmak here, ATF is rubbish as a manual box lubricant, it shortens gear and bearing life and will need changing after 6K miles to keep your box in good condition.
Use the castrol 75W-90 stuff which you can get from opie oils or halfords and your box will live a lot longer.
I've put this stuff in all my TVR's over the last 10 years and it always improves gear selection and shuts things up as well.
A loud gear noise on my mates lamborghini was also cured with this stuff.
ATF may be the rover recommended stuff but it was, and still is a bodge
Matt
Use the castrol 75W-90 stuff which you can get from opie oils or halfords and your box will live a lot longer.
I've put this stuff in all my TVR's over the last 10 years and it always improves gear selection and shuts things up as well.
A loud gear noise on my mates lamborghini was also cured with this stuff.
ATF may be the rover recommended stuff but it was, and still is a bodge
Matt
Thanks for the advise all those that posted it, I changed the Castrol Dexron 3 strawberry juice for Castrol SMX honey and indeed once all was warmed up the change was much nicer. Having said that still got slight crunch 4th to 5th and in 3rd to 2nd to the point where if the speed isn't matched closely, it wont go in.
I know I've been spoiled by my previous toy (the Honda S2000 box is an absolute peach) but how much better will my LT77 box feel if expertly rebuilt. Any recommendations?
I know I've been spoiled by my previous toy (the Honda S2000 box is an absolute peach) but how much better will my LT77 box feel if expertly rebuilt. Any recommendations?
Just looking at the photos of your 'new' 4.3 would suggest the previous owner was well into track days - roll cage, harnesses, taped over lights, etc. Maybe all that track use has worn out the synchro prematurely. I use ATF in my 4.3 with no problems - gear change couldn't be sweeter.
OscarT
OscarT
Edited by OscarT on Sunday 2nd December 21:28
Chad speed said:
Thanks for the advise all those that posted it, I changed the Castrol Dexron 3 strawberry juice for Castrol SMX honey and indeed once all was warmed up the change was much nicer. Having said that still got slight crunch 4th to 5th and in 3rd to 2nd to the point where if the speed isn't matched closely, it wont go in.
I know I've been spoiled by my previous toy (the Honda S2000 box is an absolute peach) but how much better will my LT77 box feel if expertly rebuilt. Any recommendations?
A properly rebuilt LT77 has a very sweet change. Mine was done by Ken Tomlinson at N&T Transmissions in Over Whitacre. (near Coleshill) and the difference is huge. Very smooth, light (when warm) positive, no synchro noise at all, and runs nice and cool on the SMX. Very slight drag in the 1 - 2 change when VERY cold, but otherwise its like a a bolt action rifle. I know I've been spoiled by my previous toy (the Honda S2000 box is an absolute peach) but how much better will my LT77 box feel if expertly rebuilt. Any recommendations?
I had to take the box to Ken, but the rebuild itself, all in, was only a couple of hundred quid (that was a few years ago)
Andy
Edited by andymadmak on Monday 3rd December 14:13
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