TH350 behind a 1.9

jeepslam

New member
Joined
Nov 23, 2018
Location
NC
TDI
2002 ALH
The direction, gearing, and overall size seem to be correct, so can someone list the pros and cons of mating a Chevy or gmc TH350 to a vw 1.9 tdi?
 

PakProtector

Veteran Member
Joined
Jan 5, 2014
Location
AnnArbor, MI
TDI
Mk.4's and the Cummins
Well...have you got a converter that is matched to the TDI's output and your preferences? Lock up would be nice. So for that matter would be the missing OD/4th gear. T700R4 maybe?
cheers,
Douglas
 

GoFaster

Moderator at Large
Joined
Jun 16, 1999
Location
Brampton, Ontario, Canada
TDI
2006 Jetta TDI
What do you want to operate with this?

That's an obsolete transmission. Low gear isn't low enough, high gear isn't high enough, there's too much space between gears, most of them didn't have lock-up torque converters and the few that did (1979-1984, and not all of them) the lock-up clutch has limited torque capacity.

Why this, instead of something better?
 

jmodge

Top Post Dawg
Joined
Jun 18, 2015
Location
Greenville, MI
TDI
2001 alh Jetta, RC2 w/.205's 5speed daily summer commuter and 2000 alh Jetta 5spd swap, 2" lift, hitch, stage 3 TDtuning w/.216's winter cruiser, 1996 Tacoma ALh
700R4 is the same trans with overdrive. Torque converter for a light car would give a higher stall than one for a heavy vehicle and vise versa. No vacuum module, but it has a kickdown cable, or TV as it is called. Actuated by a mechanical throttle. If adjusted improperly it changes the clutch pressure and failure comes quite quickly, I don't know how that could be made to work with DBW. Maybe TH350 could be set up to shift manually. Coolair is a tranny man, might get some facts if you pm'd him.
 

jmodge

Top Post Dawg
Joined
Jun 18, 2015
Location
Greenville, MI
TDI
2001 alh Jetta, RC2 w/.205's 5speed daily summer commuter and 2000 alh Jetta 5spd swap, 2" lift, hitch, stage 3 TDtuning w/.216's winter cruiser, 1996 Tacoma ALh
But, as stated, gearing may not be optimal, depending what you are doing.
 

PickleRick

Veteran Member
Joined
Nov 29, 2017
Location
Greenville sc
TDI
05 GLS BHW sedan 5 speed conversion. BHW Carver SantaCruz in progress
The th350 is cheap. Its cheap to have rebuilt. Plenty of speedo gear options so you can play with your rear end gearing/tire size and keep an accurate speedo. IIRC the th400 and th350 have the same torque converter, the th400 was mated to a gm 6.2 diesel so a stock replacement diesel torque converter is available. If not there is a huge selection of th350 torque converters in the aftermarket world.

No overdrive as stated, run a transmission cooler and she'll be very reliable. My 79 transam came with a 2:41 gear rear end, a th350 and a very low factory compression 6.6 sub 200 hp 403 engine. It was not impressive off the line but a heavy motor, heavy car...it was still faster off the line than say my 1989 v6 bronco 2 or any of my stock gasser fj60 or fj40 land cruisers.

The 700r4 would be a better all round transmission but if you already have the tranny, are on a budget and just want an around town beater car she'll work for you. If the vehicle is light enough and you can keep the gearing on the rear end high enough you may be able to get to 65-70mph before exceeding 3000 or so rpms. Plenty of gear calculators out there via a quick google search. Put in your tranny specs, your gearing and tire size. Add about 15% more rpms to account for drag, tire size variations and other real life factors.

My bhw passat with dvz transmission its 70 to 75 at about 3000 rpms, has no issue with it...i limit my hwy cruising at 75 because mpgs drop after that. When posted speed limit is 70 i get passat like im not moving even doing 75. My passat is my work commuter so i don't drive the hwy often.

The th350 can be made to shift manually. Plenty of aftermarket valve bodies available, quite popular tranny for the strip.
 
Last edited:

jmodge

Top Post Dawg
Joined
Jun 18, 2015
Location
Greenville, MI
TDI
2001 alh Jetta, RC2 w/.205's 5speed daily summer commuter and 2000 alh Jetta 5spd swap, 2" lift, hitch, stage 3 TDtuning w/.216's winter cruiser, 1996 Tacoma ALh
TH400 has a lower 1st gear than the 350, same as 4l80 compared to 4l60. Same trans with O.D. I have a K5 on the hunting property with a 6.2 and TH350. But if you don't have a mechanical throttle, how do you work the tv cable to control clutch pressure?
 

PickleRick

Veteran Member
Joined
Nov 29, 2017
Location
Greenville sc
TDI
05 GLS BHW sedan 5 speed conversion. BHW Carver SantaCruz in progress
Several people have used a standard throttle cable/oem pedal in the floor pan and mounted the vw pedal in the engine bay, you would have to find a way to attach the tv cable to the throttle pedal

Or use one of the better 4l60e or 4l80e(needs plenty of space) which do not use a tv cable.
 

GoFaster

Moderator at Large
Joined
Jun 16, 1999
Location
Brampton, Ontario, Canada
TDI
2006 Jetta TDI
A 700R4 is a non-electronic transmission except for torque converter lockup and (possibly) shifting into overdrive. It has a lower low than a TH350 and it has overdrive and lockup.

A 4L60 (without "e") is a 700R4 by a different name. These weren't around for long (early nineties).

A 4L60E is the same thing but is an electronically controlled transmission. It will have to be used in conjunction with a stand-alone transmission controller. Given that these transmissions are widely used in hot-rodding applications, that shouldn't be a major obstacle.

Given rather enormous aftermarket support, you have your pick of torque converters.

The bad thing is that due to wide ratio spacing, it will not be happy about having the torque converter locked through a shift, and due to being an old design, it will not be happy about being lugged down in overdrive with the torque converter locked. The OEM calibration shifted all the way through the gears with the converter unlocked, then locked it in overdrive, and if the driver as much as breathes on the accelerator pedal, it unlocks again. Lots of older transmission designs are like this.
 

jmodge

Top Post Dawg
Joined
Jun 18, 2015
Location
Greenville, MI
TDI
2001 alh Jetta, RC2 w/.205's 5speed daily summer commuter and 2000 alh Jetta 5spd swap, 2" lift, hitch, stage 3 TDtuning w/.216's winter cruiser, 1996 Tacoma ALh
The direction, gearing, and overall size seem to be correct, so can someone list the pros and cons of mating a Chevy or gmc TH350 to a vw 1.9 tdi?
Looks like we wandered a bit off of the TH350, outwardly, those family of trannys are the same. From TH350 through 4l60e and TH400 through 4l80e.

The issue, I think, would be getting them to shift behind a 1.9 and depending if you have mechanically or electrically controlled throttle. TH350 has a vacuum module. Maybe contacting some of the companies who do diesel conversions and make a Chevy adapter to see if they have done it.
 

jmodge

Top Post Dawg
Joined
Jun 18, 2015
Location
Greenville, MI
TDI
2001 alh Jetta, RC2 w/.205's 5speed daily summer commuter and 2000 alh Jetta 5spd swap, 2" lift, hitch, stage 3 TDtuning w/.216's winter cruiser, 1996 Tacoma ALh
The 700r4 in my K5 has been converted to hydraulic lockup and is controlled by the tv cable. Could Be remembering wrong, but I think the fella who rebuilt it said lockup occurs in 3rd and 4th gear. At any rate, controlling hydraulic pressure for shifting is the issue with that one. Good durable trans, but if that tv cable isn’t tight, 3-4 clutch pack gets toasted. I would be interested in hearing if or from someone who did that. Or with the TH350 that uses a vacuum module. Have you seen an actual example? Pretty curious and skeptical, which is not to say someone didn’t figure something out. I still think a manua pump with a throttle cable hooked to a 700r4/4l60 would best possibility. And if using the electronic trans, how to synchronize control modules
 

jmodge

Top Post Dawg
Joined
Jun 18, 2015
Location
Greenville, MI
TDI
2001 alh Jetta, RC2 w/.205's 5speed daily summer commuter and 2000 alh Jetta 5spd swap, 2" lift, hitch, stage 3 TDtuning w/.216's winter cruiser, 1996 Tacoma ALh
What was hooked to the early GN 350 diesel and how was that done? Stanadyne mechanical pump I believe to a turbo 350?
 

jmodge

Top Post Dawg
Joined
Jun 18, 2015
Location
Greenville, MI
TDI
2001 alh Jetta, RC2 w/.205's 5speed daily summer commuter and 2000 alh Jetta 5spd swap, 2" lift, hitch, stage 3 TDtuning w/.216's winter cruiser, 1996 Tacoma ALh
K5 on property actually has a 700r4 not 350 behind 6.2, mechanical on that also. So there are a coupl models to work from.
 

GoFaster

Moderator at Large
Joined
Jun 16, 1999
Location
Brampton, Ontario, Canada
TDI
2006 Jetta TDI
You are prodding my memory banks. Friend of mine, long ago, picked up a diesel Chevrolet G-van with a blown engine, cheap. (6.2 non turbo diesel). What was in the van was a non lockup TH350 without overdrive, which was not the original transmission for the application, it should have been an overdrive 700R4. Problem there is that you have a crankshaft 3 inches diameter on the input side of a torque converter, the other side of which (trans input shaft) is maybe 1 inch diameter ...

He deduced that the 700R4 (which has a mechanical load sensing cable) blew up, and the original owner dropped in a TH350 (which has a vac modulator) but without anywhere to hook the vac modulator up to, they just left it unconnected ... so the trans would simply always shift at max revs ... and that led to the 6.2 blowing up ... and that led to the frustrated owner selling off the remains cheap.

With a replacement engine and a built 700R4, it was fine ... well, as fine as a GM G-van with a non-turbo 6.2 will be ...
 

jmodge

Top Post Dawg
Joined
Jun 18, 2015
Location
Greenville, MI
TDI
2001 alh Jetta, RC2 w/.205's 5speed daily summer commuter and 2000 alh Jetta 5spd swap, 2" lift, hitch, stage 3 TDtuning w/.216's winter cruiser, 1996 Tacoma ALh
Yeah, that is why I wondered if a TH350 could be made to shift manually. The only way I could see it working.
700r4 or 4l60 seems like it could work attached to a 1.9 with mechanical pump, just have to take care in setting the cable. There are blueprints online that I used when I put vortec heads on my '90 K5. They were on a hotrod site and if I can find them again I will post a link.
The 1.9 has a wider powerband than those 6.2's so I think it would like it. Trans might eat a lot of power, but it would be kinda cool in something light.
 

GoFaster

Moderator at Large
Joined
Jun 16, 1999
Location
Brampton, Ontario, Canada
TDI
2006 Jetta TDI
Manual shift control (manual valve body) for the non-electronic transmissions is not a problem, these transmissions are commonly used in drag racing and it's done all the time for that. Doesn't fix the line pressure headache, though. I think it will still want the TV hooked up (and correct! - looks like it's fussy) to get it to shift right, and at that point, you might as well just let it do its own shifting. Wrongly chosen manual shift (you know it's going to happen!) plus wrong line pressure looks like it could easily cook something.

It would sure help if the original poster would chime in and explain what it is that they are trying to do.
 

jmodge

Top Post Dawg
Joined
Jun 18, 2015
Location
Greenville, MI
TDI
2001 alh Jetta, RC2 w/.205's 5speed daily summer commuter and 2000 alh Jetta 5spd swap, 2" lift, hitch, stage 3 TDtuning w/.216's winter cruiser, 1996 Tacoma ALh
Yeah, an update by op would be nice. We may hear in time. Nice topic and food for thought at any rate.
 

TDIsyncro

Veteran Member
Joined
Nov 14, 2005
Location
Saskatoon, SK
TDI
Audi/TDI x 2
I have been running a 4l60e on my TDI for almost 3 years now. It is a great match for the torque/power. I do not think I would be happy with a th350 as it's nice to have the overdrive gear. Using USShift to control it. Using a custom built torque converter. We have a guy that builds them locally. I have have lockup set in 2nd gear and up. I can chug around town in 2nd or 3rd gear as low as 1350 rpm with lockup engaged pulling good torque and the transmission behaves really nice. There is a bit too much concern in the posts above.
 

jmodge

Top Post Dawg
Joined
Jun 18, 2015
Location
Greenville, MI
TDI
2001 alh Jetta, RC2 w/.205's 5speed daily summer commuter and 2000 alh Jetta 5spd swap, 2" lift, hitch, stage 3 TDtuning w/.216's winter cruiser, 1996 Tacoma ALh
Good info, thanks for posting that
 

PickleRick

Veteran Member
Joined
Nov 29, 2017
Location
Greenville sc
TDI
05 GLS BHW sedan 5 speed conversion. BHW Carver SantaCruz in progress
I agree 100% that the 4l60e would be a better on road tranny but if i were building a yj, fj40 or similar short wheel base off road rig and needed a cheap, strong, compact transmission the th350 would be a go to. I have always been impartial to stick shifts but the automatics are far better for off road/rock climbing duty especially if one must use the brake and throttle at the same time. A hand throttle in a TBW set up would take some for thought and even then many times on rocks you need both hands on the wheel. Pre power steering rigs are 100% 2 handed on rocks. This is important to remember due to many emissions regulated areas requiring diesel swapped vehicles be past a certain age (usually 70s)

The drive shaft angle for a dual boxes on a SWB vehicle with a 4l60e would leave much to be desired and in many set ups impossible.

But a 4l60e would allow me to drive my off road toy 85mph to the Moab...some 5 day trek, beat the crap out of it on the rocks and IF i dont destroy it i can drive all the way back home...if she'll fit (that's what she said)
 

jeepslam

New member
Joined
Nov 23, 2018
Location
NC
TDI
2002 ALH
I will blame my wanting the automatic on my wife to whom I am married. Her bad left knee does not allow her to operate a clutch. I'm building an open hood rat rod, and have a 2002 1.9 motor pulled from a Jetta I bought back from the insurance company for $290. The rat rod WAS getting an I6 out of a '76 Firebird, but this tdi sounds and looks MUCH cooler. Really any automatic trans would be fine, I just happen to have a lockup th350 on hand. I could sell the 350 easily and put the $150 towards the correct trans. FWIW, the 1.9 is not getting built, and it will be stripped down. No a/c, no pb, no ps, no egr. The stock 90hp will be enough for the 1700 lb car. I have not sent the computer off for the deletes; that will happen after the holidays. Any and all ideas are welcome.
 

ManicMechanic

Veteran Member
Joined
Oct 6, 2017
Location
Saint Cloud, Florida
TDI
03 Golf, 00 Golf, 02 Beetle
With a build like the you should be able to get away with a non overdrive trans. Gear options are near unlimited in car axles. Dodge gen 1 Cummins ran a non overdrive trans with a 307 rear end and it worked fine.
 

PickleRick

Veteran Member
Joined
Nov 29, 2017
Location
Greenville sc
TDI
05 GLS BHW sedan 5 speed conversion. BHW Carver SantaCruz in progress
The adapter that fits the th350 will work on the 700r4/460le so future upgrade on the tranny is always there.

Sounds like a fun build. You'll spend as much on a stand alone computer for the 4l60e as you will om the transmission itsself.

I used witbread for my tuning (malone) there are sevral others here that do that as well and they are more active on the forum.
 

GoFaster

Moderator at Large
Joined
Jun 16, 1999
Location
Brampton, Ontario, Canada
TDI
2006 Jetta TDI
OK now we are getting somewhere! If the car only weighs 1700 lbs then it won't need deep gearing for starting off from a stop, and if it has terrible aerodynamics (which is likely) then it won't want a tall top gear, and it's not likely something that you want to go exploring autobahn top speeds with.

Danger: Calculations ...

If your tires are 28" tall (guess) then they will be doing 720 revs per mile, i.e. 720 rpm. Multiply that by final drive ratio to get revs at 60 mph.

If you target 2400 rpm at 60 mph the car will still do 90 mph if you want to ... probably fast enough for what you are talking about. That would need a final drive ratio somewhere near 3.33:1 so pick something close to that or maybe a smidge lower.

The drive force in top gear at stock 155-ish lb.ft, assumed 85% drivetrain efficiency, 3.33:1 final drive, 28" tall wheels will be 376 lbs. In first gear 2.52:1 it will be 948 lbs, enough to accelerate at close to half a "g" in that light car. Starting off from a stop it would be higher due to torque converter multiplication. 4000 rpm in 1st gear would be around 40 mph not counting torque converter slippage (so in reality the 1-2 shift would be a little earlier). It will carry 2nd (1.52:1) to around 60 mph.

Won't be a barn burner, but in such a light vehicle, it'll do.

The lack of a vacuum signal to the vac modulator remains a nuisance, unless you install a full manual valve body.
 

ManicMechanic

Veteran Member
Joined
Oct 6, 2017
Location
Saint Cloud, Florida
TDI
03 Golf, 00 Golf, 02 Beetle
I'm not sure about the th350 but I know the th400 can have it's vacuum modulator replaced with a manual one. I bought a Cummins 3.9 out of a bread truck and it had a manual modulator with a control rod going to the throttle.
 
Top