Isuzu transmission advice needed

Drivetrain problems

Moderators: theelanman, nitroman, Specky, clemo, dapinky, Dave Eds, GeoffSmith, Nige, DaveT, Sy V, Elanlover, muley, Enright, algirdas

Isuzu transmission advice needed

Postby Sleeka » Wed 23.11.2016, 07:09

So I was bringing my "new to me" Lotus home when the gearbox went out (no prior indication just broke when starting to go after filling up with gas). Towed car to Canada and now I have to decide what to do. The transmission shop has verified broken gears but they have not pulled it all apart to see what exact gears need replacing. They have pulled it out and say that the clutch is dead as well (probably original so).

I have purchased a replacement from a non turbo Isuzu Impulse. (great deal and really low mileage). My concern is will this transmission break easily from the extra power of the turbo or is the difference between the lotus and impulse only gear ratios? I can live with less top end and faster 0-60. I assume I would have to get a stronger race clutch to handle the extra power (this is me assuming I would have to use a non turbo clutch to match the exact gearbox)

Or is it worth getting it pulled apart and attempt to find replacement parts?

I would rather have a stock replacement but it will probably cost me at least $900 more to go stock.

Should I fear the impulse gearbox?


Kristopher
User avatar
Sleeka
Newbie
 
Posts: 28
Joined: Wed 08.10.2008, 03:15
Location: Port Moody, BC

Re: Isuzu transmission advice needed

Postby Brit-Car-Nut » Wed 23.11.2016, 14:28

The Turbo and NON-Turbo gearboxes are different from each other due to the NON-Turbo gearbox having a taller final drive gearset installed. The difference is NOT SMALL, you will run out of engine before you get up to speed. You need to use the TURBO clutch as it is much larger (to handle the additional power). It would be better to fix the original box than downgrade it.

What exactly happened? What broke? 5th gear has always had an attachment issue and the nut will back off locking it up but that is usually repairable.

Give us some more details and search the forum for the specific symptoms and you will likely find a decent solution.

There are too many M100s out there now with incorrect parts installed and it would be nice if you don't make another Frankenstein.
HD Replacement Shift Cables and Short Shift Kits still available
HD Replacement Shift Cable and Short-Shift Kit prices
Please contact me via eMail, not by PM
Download Manuals Here
Brit-Car-Nut
God
 
Posts: 3980
Joined: Tue 03.07.2007, 17:07
Location: Charlotte, NC USA

Re: Isuzu transmission advice needed

Postby Simon_P » Wed 23.11.2016, 14:53

Never heard of an M100 gearbox "break" the cables break or the 5th gear nut comes loose.
Simon_P
God
 
Posts: 1006
Joined: Fri 06.08.2004, 12:33
Location: Kent UK

Re: Isuzu transmission advice needed

Postby Sleeka » Wed 23.11.2016, 15:46

I was stopped to get gas and when I went to reverse it didn't want to go so I put it in forward and it made a big crunch sound. So I put it in neutral and roll it out of the way. It was difficult to put into any fear and it wasn't moving when I did. Then after wiggling the gear shift I found I had reverse while in neutral. Then I believe I had 5th as it would go with lots of clutch. Wiggling the stiff shifter and crunch again. All while barely moving.

So then the car doesn't move at all even with the clutch pushed in (car would not roll and was locked up). I found if I rocked the car back and forth it would break free for one revolution and then freeze again. I got it on a tow dolly and brought it home. The gear shift at this point would barely move forward and back (not fully) and not at all side to side.

It has the upgraded cables already and I had disconnected them to make sure it wasn't just an alignment issue. I had read all the posts in this forum that were related so I had hope that the fifth gear nut was just loose. But the transmission shop pulled off the cover and said there were broken gears. I would have to pay for their time to pull it apart and investigate (this is my dilemma because I don't want to dump lots of extra money just to possibly fix). Also there are not many resources for fears that I have found other than SJS which is crazy expensive for each gear or synchro. I found a link to an Isuzu rebuild kit but that doesn't give me the lotus gearing.

I agree that original is better but I can't find any resources to make this thing right again. Also the 4.1 ratio of the box is offset a bit by the taller 1,2 and 3 gears. Not ideal but not insane either I wouldn't think. An online calculate tot suggests that at 3500 rpm I would be at 61 mph instead of 70.

If I had an option for a replacement gear set I would probably be fine but this is not easy to come by here and there are no local Elan gurus to take this on. And I only have thirty days as this is getting imported the government wants it inspected in the next thirty days.

Advice please.
User avatar
Sleeka
Newbie
 
Posts: 28
Joined: Wed 08.10.2008, 03:15
Location: Port Moody, BC

Re: Isuzu transmission advice needed

Postby Brit-Car-Nut » Wed 23.11.2016, 19:19

The Single Cam SOHC Impulse and the single cam GEO Storm/Chevy Storm have close to the stock ratios including the correct 3.83 final drive but the side gears in the diff (where the driveshafts go) have a smaller ID so the M100 driveshafts won't fit. The GEO Storm GSI Twin Cam DOHC has the 4.11 final drive but larger side gears so the M100 driveshafts should fit. I am pretty sure I have one or more of each so I will try a driveshaft in what I have laying around.

Going from a 3.8 to a 4.1 diff is a huge change. You will be shifting sooner to get to higher gears and running at 3500 and only being at 60 mph means that on normal highways, you will be in the 4000 rpm ranges which is not good for fuel economy and longevity of the engine life.

I would pull the gearbox and take it apart to see exactly what is broken. It is really rare to have a gearbox self destruct.
HD Replacement Shift Cables and Short Shift Kits still available
HD Replacement Shift Cable and Short-Shift Kit prices
Please contact me via eMail, not by PM
Download Manuals Here
Brit-Car-Nut
God
 
Posts: 3980
Joined: Tue 03.07.2007, 17:07
Location: Charlotte, NC USA

Re: Isuzu transmission advice needed

Postby Rob P » Wed 23.11.2016, 19:41

Had a gearbox issue a year or so ago, couldn't select first or second gear, wasn't a cable issue but diagnosed to the selector fork.
simplify and add lightness
1991 Norfolk Mustard Yellow SE - Gone but will never be forgotten :-)
1969 Lotus Elan S4 - Wedgewood Blue
User avatar
Rob P
Fanatic
 
Posts: 710
Joined: Wed 20.02.2013, 17:35
Location: Preston, Lancs

Re: Isuzu transmission advice needed

Postby Sleeka » Wed 23.11.2016, 21:15

The biggest problem is where can I get ahold of replacement parts? SJS has them listed but at high cost. Anything in the US? Would some parts from the Isuzu work like the sychros?

Thanks for the advice so far.
User avatar
Sleeka
Newbie
 
Posts: 28
Joined: Wed 08.10.2008, 03:15
Location: Port Moody, BC

Re: Isuzu transmission advice needed

Postby dapinky » Wed 23.11.2016, 21:50

Sleeka,

I have never actually taken a gearbox apart (for the Elan!), but would expect that most, if not all, of the components would be shared with other 'boxes of the same vintage.

I can see that Lotus would want the 'best' ratios for the job, but I can't believe that they'd spend money on bespoke items unnecessarily. As such, i would expect all 'service' items (sincro rings, bearings, seals) to be common accross the range with the Storm items, with a gear set from a 'standard' box for one of the models, with perhaps a final drive from another - but all from the GM parts box.

I would expect a competent gearbox reconditioner to be able to source any parts you may need locally (but that is a guess as my knowledge of Canadian availability is very limited), or at least, from the USA.

There was a good write-up and video of someone stripping down an Impulse (or maybe a Storm/Sunfire) gearbox on the Isuzone forum, but I don't have a link to it - may be worth a search on there?
Dave

Just the one now, but this one's mine! - and it will be finished eventually.....

go on - click this link - you know you want to!
User avatar
dapinky
Moderator
 
Posts: 8019
Joined: Sun 15.10.2006, 12:54
Location: As far west as you can get in West Wales before you become Irish (Pembroke Dock).

Re: Isuzu transmission advice needed

Postby Brit-Car-Nut » Wed 23.11.2016, 23:00

Sleeka wrote:The biggest problem is where can I get ahold of replacement parts? SJS has them listed but at high cost. Anything in the US? Would some parts from the Isuzu work like the sychros?

Thanks for the advice so far.

As I remember it, there were two different synchro designs used in the GM gearbox. There were "one piece" and "two piece" versions. There are two GM write-ups in the Manuals (see link below) list that might help. I believe the M100 uses the "single piece" synchros.

I remember finding a list of rebuild kits that included the synchros, seals, gaskets and other normally replaced parts. I will try to find the link but it was a long time ago.

I can help with some used gears from an open gearbox I have here and I have a couple of full gasket/seal kits from GM available. I also have new 5th gear nuts that can work loose. I also have some of the cases and covers.

If you only need one gear or so, MAYBE Dave Bean Engineering might have it/them, but very expensive for new parts.
Last edited by Brit-Car-Nut on Wed 23.11.2016, 23:34, edited 1 time in total.
HD Replacement Shift Cables and Short Shift Kits still available
HD Replacement Shift Cable and Short-Shift Kit prices
Please contact me via eMail, not by PM
Download Manuals Here
Brit-Car-Nut
God
 
Posts: 3980
Joined: Tue 03.07.2007, 17:07
Location: Charlotte, NC USA

Re: Isuzu transmission advice needed

Postby lotusflasherman » Wed 23.11.2016, 23:02

Sleeka wrote:So I was bringing my "new to me" Lotus home when the gearbox went out (no prior indication just broke when starting to go after filling up with gas). Towed car to Canada and now I have to decide what to do. The transmission shop has verified broken gears but they have not pulled it all apart to see what exact gears need replacing. They have pulled it out and say that the clutch is dead as well (probably original so).

I have purchased a replacement from a non turbo Isuzu Impulse. (great deal and really low mileage). My concern is will this transmission break easily from the extra power of the turbo or is the difference between the lotus and impulse only gear ratios? I can live with less top end and faster 0-60. I assume I would have to get a stronger race clutch to handle the extra power (this is me assuming I would have to use a non turbo clutch to match the exact gearbox)

Or is it worth getting it pulled apart and attempt to find replacement parts?

I would rather have a stock replacement but it will probably cost me at least $900 more to go stock.

Should I fear the impulse gearbox?

Kristopher


Don't know whether it's just me but I'm having a syntax problem with the descriptions - "gearbox went out, just broke" and "clutch is dead"...

Clutch, when worn 'slips', or if the pressure plate is sticking on the input shaft 'drags' or 'won't disengage'...

Gearbox - 'won't select gears', 'won't change gear' or 'won't transmit drive'... Can't make any useful comment or advice on 'went out' or 'just broke'...

My first SE did 150,000 miles with only a gearchange cable failure (I had both replaced) and a few brake discs needed on top of routine servicing, and the other two have done 50,000 with only servicing and an alternator... Not a lot of history on gearbox failures on the Forum as far as I know. - few indent spring/ gear selection issues and plenty of cable failures.

UK M100 gearbox here with 84k miles on it...www.ebay.co.uk/itm/LOTUS-ELAN-M100-LAA-GEARBOX-/192013326379?

That looks like about $312 but don't know shipping costs but might be worth investigating. If he won't ship to US I can probably act as an intermediary...
Phil

Leave me alone, I think I know what I'm doing.
Cars: Subaru Forester 2.5XTN, Eclat Riviera, brace of Pacific Blue SE's, Elan+"S.... and now a Collapso SE
User avatar
lotusflasherman
God
 
Posts: 2171
Joined: Fri 05.09.2008, 00:14
Location: Hadleigh, 15m west of Ipswich or 800 miles south (Cap d'Agde)

Re: Isuzu transmission advice needed

Postby Brit-Car-Nut » Wed 23.11.2016, 23:25

[quote="lotusflasherman"]
UK M100 gearbox here with 84k miles on it...www.ebay.co.uk/itm/LOTUS-ELAN-M100-LAA-GEARBOX-/192013326379?/quote]
Phil: The LAA is a NA gearbox. The Turbo gets LAB - the other one...

Gearbox Listing2.jpg
You do not have the required permissions to view the files attached to this post.
HD Replacement Shift Cables and Short Shift Kits still available
HD Replacement Shift Cable and Short-Shift Kit prices
Please contact me via eMail, not by PM
Download Manuals Here
Brit-Car-Nut
God
 
Posts: 3980
Joined: Tue 03.07.2007, 17:07
Location: Charlotte, NC USA

Re: Isuzu transmission advice needed

Postby lotusflasherman » Wed 23.11.2016, 23:53

Brit-Car-Nut wrote:
lotusflasherman wrote:UK M100 gearbox here with 84k miles on it...www.ebay.co.uk/itm/LOTUS-ELAN-M100-LAA-GEARBOX-/192013326379?/quote]
Phil: The LAA is a NA gearbox. The Turbo gets LAB - the other one...

Gearbox Listing2.jpg


Is it only the final drive different, or are other things different for Turbo?

Same seller has box from S2 at slightly higher price (about $435) ..... www.ebay.co.uk/itm/LOTUS-ELAN-M100-S2-SE-TURBO-GEARBOX-/201702897195
but is 'quiet' about the mileage... I'm wondering why..
Phil

Leave me alone, I think I know what I'm doing.
Cars: Subaru Forester 2.5XTN, Eclat Riviera, brace of Pacific Blue SE's, Elan+"S.... and now a Collapso SE
User avatar
lotusflasherman
God
 
Posts: 2171
Joined: Fri 05.09.2008, 00:14
Location: Hadleigh, 15m west of Ipswich or 800 miles south (Cap d'Agde)

Re: Isuzu transmission advice needed

Postby Sleeka » Thu 24.11.2016, 00:06

Sorry for the confusing wordage. I do mean things broke and not slipping or grinding. The clutch felt fine so I was a little surprised that the shop said it needed replacement (but again while its all being done its still a good idea). Definitely not the issue. Also cables were not the cause.

They are taking it apart on Monday to get a better idea on whats gone wrong with it. The higher gears were the same ratio between the Isuzu and Lotus so maybe the gearbox I have will be useful for at least those parts if needed.
User avatar
Sleeka
Newbie
 
Posts: 28
Joined: Wed 08.10.2008, 03:15
Location: Port Moody, BC

Re: Isuzu transmission advice needed

Postby lotusflasherman » Thu 24.11.2016, 00:30

Sleeka wrote:Sorry for the confusing wordage. I do mean things broke and not slipping or grinding. The clutch felt fine so I was a little surprised that the shop said it needed replacement (but again while its all being done its still a good idea). Definitely not the issue. Also cables were not the cause.

They are taking it apart on Monday to get a better idea on whats gone wrong with it. The higher gears were the same ratio between the Isuzu and Lotus so maybe the gearbox I have will be useful for at least those parts if needed.


While it's out clutch friction plate change may be a good idea if it looks thin but beware of project creep - 'pressure plate because diaphragm may go slack and what about a thrust bearing.. etc.. How may miles has the car done?

Of course if you're paying somebody to do 'the spannering' it's always a judgement about a few extra bucks for those extra bits against a lot more if they need doing soon after... and the 'why didn't I do it then ? question...

20/20 hindsight is a wonderful thing we all have...
Phil

Leave me alone, I think I know what I'm doing.
Cars: Subaru Forester 2.5XTN, Eclat Riviera, brace of Pacific Blue SE's, Elan+"S.... and now a Collapso SE
User avatar
lotusflasherman
God
 
Posts: 2171
Joined: Fri 05.09.2008, 00:14
Location: Hadleigh, 15m west of Ipswich or 800 miles south (Cap d'Agde)

Re: Isuzu transmission advice needed

Postby Sleeka » Thu 24.11.2016, 02:00

The car has 80,000 miles on it.
User avatar
Sleeka
Newbie
 
Posts: 28
Joined: Wed 08.10.2008, 03:15
Location: Port Moody, BC

Re: Isuzu transmission advice needed

Postby lotusflasherman » Thu 24.11.2016, 03:47

Brit-Car-Nut wrote:
lotusflasherman wrote:UK M100 gearbox here with 84k miles on it...www.ebay.co.uk/itm/LOTUS-ELAN-M100-LAA-GEARBOX-/192013326379?/quote]
Phil: The LAA is a NA gearbox. The Turbo gets LAB - the other one...

Gearbox Listing2.jpg


Just had an interesting read through Section 47 of the Parts Manual ... :lol:

It appears only difference between the LAB & LAA gearboxes is the number of teeth on the diff' gear ring (69 teeth Turbo A100F6251S, or 70 teeth NA .. 6252S) and the output shafts (A100F6202S or 6203S) where the teeth need to be different to correctly mesh with appropriate diff gear. All other shafts bearings etc are common to both. I also looked to see if a different speedo drive gear was used but haven't found one so guess they reckoned a change of 1 in 69 (1.45%) didn't warrant a change.

Buying a secondhand NA gearbox of moderate mileage might be a better option as it will certainly have had an easier life than one from an SE - and you'll know it wasn't from a 'chipped' turbo car that might have given it an even harder life.
Only needs the diff gear ring and output shaft to be in good condition to swap from the one that's coming out - but Sod's Law says that's probably what has failed :shock:
Phil

Leave me alone, I think I know what I'm doing.
Cars: Subaru Forester 2.5XTN, Eclat Riviera, brace of Pacific Blue SE's, Elan+"S.... and now a Collapso SE
User avatar
lotusflasherman
God
 
Posts: 2171
Joined: Fri 05.09.2008, 00:14
Location: Hadleigh, 15m west of Ipswich or 800 miles south (Cap d'Agde)

Re: Isuzu transmission advice needed

Postby Sleeka » Thu 24.11.2016, 04:01

That's interesting. Then it may be possible to put the diff gear into the Isuzu to change its dif ratio to match the lotus. It would still have taller 1,2 and 3 gears though.
User avatar
Sleeka
Newbie
 
Posts: 28
Joined: Wed 08.10.2008, 03:15
Location: Port Moody, BC

Re: Isuzu transmission advice needed

Postby Sleeka » Thu 29.12.2016, 07:50

Thanks everyone for be advice. It's finally fixed after a month. I'm not sure how it happened but 4th and 5th gears broke. Luckily those are the only gears that I could reuse from the Isuzu transmission. New bearings, seals and clutch and I have finally been able to bring it home.

Hopefully nothing else major goes wrong for at least the next year. I am now officially a Lotus Elan owner.
User avatar
Sleeka
Newbie
 
Posts: 28
Joined: Wed 08.10.2008, 03:15
Location: Port Moody, BC

Re: Isuzu transmission advice needed

Postby tigerdog » Thu 29.12.2016, 20:14

Sleeka wrote:The biggest problem is where can I get ahold of replacement parts? SJS has them listed but at high cost. Anything in the US?...


Dave Bean Engineering acquired the remainder of Lotus US's M100 spares. http://www.davebean.com/ Not cheap but one good source.
http://www.lotusm100parts.com/index.php has historically had some items otherwise hard to find in the USA.

I've also seen a few M100s in salvage listings. There's a complete silver car listed elsewhere on the board. Still strikes me as truly strange, what happened to your car.
"Refitting is the reverse sequence to removal, but you swear in different places."
User avatar
tigerdog
God
 
Posts: 2591
Joined: Tue 20.03.2007, 09:07
Location: San Diego, CA, USA


Return to Transmission, and Clutch

Who is online

Users browsing this forum: No registered users and 1 guest

cron