LT177 vs T5 RELIABILITY. FACT OR FICTION.
Discussion
Resonses from both T5 and LT177 owners required to try to find out whether the reliability of the LT177 g'box is based on fact or myth and legend. I don't want the stock answer straight from Steve H's book (although by the way I think this book is a must for all Griff and Chim owners). Actual, known cases of failure is what is required.
Let's keep this separate from gear ratios etc which may cloud the issue of reliability - perhaps we'll have some fun with that later.
I'm not counting failures with the remote linkages to the box because that's a separate thing, but I think we will count failures with the road speed sensor because it is built into the LT177 (but not the T5).
To identify which box you have, LT177 reverse gear position is left-forward, T5 is Right-back. T5 was introduced sometime during '94.
I'll kick off.
Mine's an LT177, and the road speed sensor has failed once. otherwise no reliability problems.
I look forward to your responses.
Let's keep this separate from gear ratios etc which may cloud the issue of reliability - perhaps we'll have some fun with that later.
I'm not counting failures with the remote linkages to the box because that's a separate thing, but I think we will count failures with the road speed sensor because it is built into the LT177 (but not the T5).
To identify which box you have, LT177 reverse gear position is left-forward, T5 is Right-back. T5 was introduced sometime during '94.
I'll kick off.
Mine's an LT177, and the road speed sensor has failed once. otherwise no reliability problems.
I look forward to your responses.
The LT77 has a reputation for having a good gear change quality, and for being strong enough to take around 300 lb-ft reliably. (Incidentally the name is LT77, not LT177. The name comes from the 77mm layshaft spacing.) My experience supports this reputation.
My 160k mile V8S uses the LT77 gearbox. I've had the gearbox rebuilt several times during its life. It has been rebuilt by 'Bernie the Box' and uses his uprated output bearings. Apart from these wear-and-tear rebuilds, the 'box has been fine despite having 300 lb-ft shoved through it most of it's life and about 400 lb-ft for the last year.
However, as with any transmission component, the life can be reduced drastically if you put shock loads into the transmission for example by having an unsympathetic gear change technique.
Edited to add: the last rebuild has been done by Ken "LT77" Tomlinson.
>> Edited by GreenV8S on Thursday 13th October 13:26
My 160k mile V8S uses the LT77 gearbox. I've had the gearbox rebuilt several times during its life. It has been rebuilt by 'Bernie the Box' and uses his uprated output bearings. Apart from these wear-and-tear rebuilds, the 'box has been fine despite having 300 lb-ft shoved through it most of it's life and about 400 lb-ft for the last year.
However, as with any transmission component, the life can be reduced drastically if you put shock loads into the transmission for example by having an unsympathetic gear change technique.
Edited to add: the last rebuild has been done by Ken "LT77" Tomlinson.
>> Edited by GreenV8S on Thursday 13th October 13:26
. LT77 boxes usually kill the output bearings, synchros and oil pump. They do not like high levels of torque and will die very quickly given a lot of stick. The one on the 520 used to get rebuilt every year - it died this year after a year with the 8 throttle bodies and has been replaced with a custom close ratio box. Still cheaper than a T5 transplant. The LT77 can be improved but I tend to treat them as a consumable. I have had 5 other TVRs with t5 boxes with no problems... alright one - I ripped 16 teeth of one of the gears when the engine crank broke doing *** mph at Snetterton. Don't think that is a reliability issue.
Would I consider swapping the LT77 in a Griff to a T5? No... the costs would pay for several LT77 box rebuilds etc so why do it. If I had to choose between the two in a Griff... I would go for the T5. Chances are it would be less hassle.
Would I consider swapping the LT77 in a Griff to a T5? No... the costs would pay for several LT77 box rebuilds etc so why do it. If I had to choose between the two in a Griff... I would go for the T5. Chances are it would be less hassle.
v8 racing said:
I have never broken an lt77 even on the back of 450 bhp motors, my old saloon car racer had the same box for 4 years without a rebuild. personaly if you dont rush the gearchange they will take anything a rover engine can throw at them!
How much torque would that be putting out Rob? I think it's torque that kills gearboxes. I also think that the driver can make a huge difference. Put a rigid transmission, sticky tyres, the heaviest clutch money can buy and I reckon a clumsy driver can wreck just about any 'box. Put a more sympathetic driver in the same car and it might last for years.
Gassing Station | Griffith | Top of Page | What's New | My Stuff