My 3500s project - future daily drive


Active Member
Thanks for the response, glad about the first bit. Re the spacer - whats causes it to be needed - stroke difference ?


Well-Known Member
I remember fiddling in the bellhousing to unclip the rod to remove it to shorten, or was it to lengthen it, I cannot remember, and then trying to clip it back again. I didn't have a Harvey watching over me :rolleyes:


Staff member
First time I converted to a 5 speed, I just put a couple of 1/4 thick nuts between the cylinder and the bellhousing. Pretty sure I found some longer bolts as well.


Active Member
Another FWIW...When I had my Sd1 it would now and again get difficult to drive smoothly, especially at low speed. Eventually I found the TPS was the problem. I managed to open it and clean the wiped carbon surface with Carbon tetrachloride (probably banned now!), and this fixed the problem. There should be some sort of solvent available to do this somewhere.


Active Member
Does this "Just the relative position of the flange on the slave coupled to the length of the pushrod and the position of the release arm. " assume using the P6B pushrod, or the SD1 pushrod?


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I think the issue is using an SD1 pushrod with a 3500s slave. Best thing is to just buy a new SD1 slave to go with the LT77. This way you get a new bore and seal and the correct part.


Active Member
new slave is always a good idea, they have a tough life. I think I have replaced one in almost every car I have ever had...
Wow! Just dropped in to catch-up on the forum, and found my thread at the top!

Status with the car currently is that I pulled the engine and gearbox out in August in order to fit the lt77. I got the lt77 ready to bolt up when I realised it was making a horrible noise when turning the box by hand with reverse selected. On disassembly I found the reverse idler was pretty much destroyed, with only slight damage (thankfully!) to the layshaft gear. I then stripped everything in order to clean out the swarf that had been pumped around and have just received the last bearing I need to commence the rebuild of the box. Unfortunately other things keep getting priority and so this had pretty much crawled to a stop!
Very, Very jealous! What a terrific thread, learned a lot here.
A few questions please. Have read elsewhere that post 1976 inlets wont fit on pre 76 heads/blocks - if you got a hotwire injection system on your 3.5 that story would seem to be wrong? You seem to have had no issue with plenum clearance under the bonnet, as Quattro reported ?
Also seen is a mention of a spacer required when using a P6 clutch slave on an LT77 bellhousing - any details available please? I know you need a propshaft from an auto to fit an LT77, but not much more. Is a change required to sizes of clutch master or slave?
Re your water pump - have done 2 on a Porsche 928 as part of a cam belt change - std practice is to replace the water pump bolts, chase the block threads (no timing cover), and use anti-seize. First time I broke 2 bolts in the block, but got them out with heat, tap end with hammer, penetrene, repeat as needed. M6 bolts go in at 7 ft/lb.
Hi JP! Thanks for the kind words, yes it's been a bit of journey with the car, and I have enjoyed every minute of it! Rv8 water pumps are known to be a bit of a pain as the bolts are quite long, pretty small diameter and one (or two, I can't quite remember) go into the water jacket. Steel, aluminium and hot water and you get lovely corrosion. I now smear a product called Duralac on pretty much anything that I want to get undone again. It's used for preventing corrosion on dissimilar metals on boats. It's fantastic!

Quattro, I am away from home this weekend, but will get some pics of the gearbox stuff up when I am home, this thread is overdue a proper update!
Right, so what have i been up to? Not much really!

Last summer I spent some time getting ready for the gearbox swap, ordering parts:
and reading up again and what to do. I had a new clutch kit, slave cylinder, automatic prop, gearbox bits and bobs and I thought I was ready so I booked a day off of work in July and got cracking:

I bought myself a level gauge thingamabob so that I could check the levels and alignment of the stock running gear components relative to each other before I took everything out, I stuck this everywhere I could think of around the underside of the car so that I can make sure I get the new gearbox and transmission aligned similarly:


Then i dragged the Lt77 I had purchased a few years ago out of the garage and drained it of its oil. The magnetic drain was a bit furry, but that wasn't a major concern as I have had a few LR boxes with a Christmas tree of filings that were fine. However there were a few chunks in the bowl - its never good when oil makes a "thunk, thunk, thunk" noise as metallic debris drops out... I decided to crack on at this point as I was feeling optimistic.



I propped the bonnet open as far as it would go, got out the engine crane and set to work:

So then I had a pretty filthy engine and box on the floor, and a big empty space in the engine bay. A quick going over with some gunk and the hose sorted that out:

I then split the engine and box, and started cleaning up and painting the engine bay a bit prior to putting everything back in:

IMG_20190722_155714.jpg IMG_20190720_14055533.jpg


A few nights later I got started on the LT77. I fitted the bellhousing and shifter mechanism, and adjusted the mech as per some information I found online, fitted a new speedo drive gear from TVR parts:

IMG_20190729_192518.jpg IMG_20190729_211351.jpg IMG_20190729_221944.jpg

And it was at this point I realised I had a problem! If i've done this right, there should be a video link below:

To be continued!


Really interesting reading. Do you still work in Kingston? I occasionally use mine to go into work in Norbiton and i'm based in Hawley so it would be funny to end up in a convoy with you on the M3!


Well-Known Member
What's the thingamyjig in front of the power steering hose and heater box, connected to the accelerator linkage, and zip tied to the scuttle panel up above? Have you fixed your knackered reverse gear?
*Edit* I re-read your thread. A throttle "see-saw". Remind me, why did you have to convert to a cable operated throttle set-up? Something to do with the EFI means it can't be operated by the original linkage?
*Re-edit* Is that the throttle position sensor?
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Hi will, yes I still work in Kingston, or was- am working from home at the moment, which is saving me a fortune in petrol!

Mrtask- correct, that is the throttle cable, connected to the see saw. I decided to do it that way as I like to keep changes as reversible as possible (god knows why) and didn't want to do anything with the original pedal to convert to cable properly. Going the other way and getting the linkage setup to work on the plenum butterfly would have been a bit complicated!

Reverse gear is still not fixed, I found the reverse idler had broken up and swarf had been pumped everywhere. It is still in pieces in the garage, however they are now very clean pieces with all swarf removed and new timken bearings everywhere, it has new oil pump gears, oil pump housing and a new reverse idler. I just need to put the thing together! Will put some pictures up of the carnage I found inside and where I have got to over the weekend at some point.
Right, so at this stage I had the car with its back end up on ramps, the engine sat back in the bay and the old gearbox shoved under the car out of the weather. I also had the ropey sounding LT77 to deal with. The next logical step would have been to get the LT77 on the bench and strip it to see what had gone wrong. Only problem with that was that I didnt actually have a bench. I have made do with just an old workmate up until now, and that needed to change:

So i bought some wood:
And made a bench:

This necessitated me having a huge sort out and tidy up of the whole garage, it had become a huge mess when i did the chassis swap on the Defender last year, but eventually i got it in there (i realise it looks like i haven't tidied anything!):


So then i got down to what I wanted to do, and starting getting the box apart. On getting to fifth gear everything looked good:


But splitting the main case soon showed what had gone wrong, the reverse gear was totally destroyed. The layshaft had suffered some damage, but looked like it should be ok.




The oil pump housing was heavily scored although the pump gear didnt look too bad!
IMG_20190930_214213.jpg Whilst cleaning the pump oil way a lot of swarf came out, including this large chunk:

I went onto Rimmers to order a new reverse idler, and thought i'd check layshaft prices whilst I was there - they were listed at over £800!

Plan B was to check the LR catalogue of parts to see if anything would match the tooth counts on the SD1 part, but nothing quite did so that put an end to that. I even stripped a spare Defender LT77 to see for myself - but no dice.

I decided to therefore carry on with the layshaft I had, but to strip everything down and clean out all the swarf and renew all the bearings. This was a shame as it looks like it had been rebuilt not long before this happened, all the bearings seemed good, and the gearbox number is not a standard one - the boss where the number is stamped has been faced off and restamped with a random number.

Nice new gear arrived, love an original BL box!

IMG_20191011_145302.jpg IMG_20191011_145325.jpg

I'll show the stripdown of the box in my next post - it takes forever to dig the photos out off my network storage, there's a lot on there!